P0606 in 2026: Control Module Processor Fault — Computer, Software, Battery or Another Module? What 665 Documents and 4,655 Complaints Show

P0606 is the code people read as "my engine computer is dead." The documents say something different.

P0606 — printed by Honda as "ECM/PCM processor malfunction", by FCA as "Internal Control Processor" and by GM as "Control Module Processor Performance" — says a control module's self-test found a fault in its own processor, or that the processor's checks disagree. The module is a computer with its own checks; P0606 is the module saying "something is wrong inside me" or, in many papers, "something around me made my checks fail." It is a code about a module, not about a part you can buy off the shelf, and the module is often not the engine computer at all: in the papers we read it is also printed for a transmission computer, a brake computer, a body computer, a lighting computer, a transfer-case computer and a hybrid computer. Its neighbours are P0601 (memory checksum), P0602 (programming error), P0603 (keep-alive memory), P0604 (RAM), P0605 (ROM) and P0607 (control module performance); our guide to a check engine light that stays on covers what to do when the code is not one of these.

We went through NHTSA's index of manufacturer communications for papers that name P0606, its companion codes or an engine-computer fault, and the first search listed 499 entries and an independent second search 278 more; 441 and 223 of them come with a PDF, and one number has two PDFs: 665 files, 579 distinct documents once exact copies are set aside. We went through 316 representative documents in full, compared the other 266 revisions and copies with them line by line, and checked 83 more files, for the codes and the module's name (18 whose text would not read were checked on page images). Of the 665 files, 146 print P0606 in some form (120 as plain P0606, the rest with a suffix such as P060600 or P060694); 337 print at least one of P0601 to P0607 as a plain code (417 counting suffix forms such as P060700).

We also went through 4,655 complaints from NHTSA's file, received from January 2015 through early October 2026, that name P0606 or a companion code, or describe an engine or powertrain control module as failed, faulty, diagnosed, damaged, replaced or updated in owners' words. Each was sorted twice, independently, by the same written rules; the two sortings matched on the main category in 87% of them (4,051 of 4,655), the rest were settled by written rules, and a last check of every complaint against its full text corrected 773 of them. 4,032 describe a control-module fault on the owner's car; 623 do not. The number that matters most for this page is small: only 26 of the 4,032 print P0606 itself, and 59 print any of P0601 to P0607. Owners write "the computer failed" or "the ECM was replaced"; the code lives in dealer papers and scan printouts.

By the end you will know which of five routes your P0606 is on, what each costs, which papers and programs exist in 2026, and when to stop driving.

Claims marked 🟢 rest on a document listed in the Sources section. Claims marked ⚪ are shop-price estimates carried from our repair guides. Owner-reported figures are what people told NHTSA, published with ODI numbers, and every complaint count here comes from the 4,655 complaints sorted twice and published.

Words on this page. Engine computer (ECM, PCM, ECU): the computer that runs the engine. TCM: the transmission computer. EBCM: the brake computer on some GM trucks. DTC: a trouble code such as P0606. Bulletin (TSB, SSM, PI): a maker's repair instruction to dealers, not a recall. Reflash: loading new software into a module. RSU: a Rapid Service Update, a short-term Stellantis offer.

I built PulsCar after a $380 "full diagnostic" in Phuket in 2025 led to roughly $6,000 over six months across several shops (the story is on the About page).

What P0606 says: a module's own check failed, not a dead part

What the module reports. 🟢 GM's corporate bulletin explains the family: "Beginning in 2005, some control modules have specific codes that describe internal failures of the module." It lists P0606 as a code that "May be set in ECM, FPCM, PIM, TCM, TCCM" and adds that "Do not replace any module before understanding which module has set the DTC, before following proper eSI diagnostics and until eSI diagnostics instruct to replace the module." Honda's paper names the same code "ECM/PCM processor malfunction"; FCA's 2023 bulletin for the 2018 Durango SRT says "Associated with DTC: P0606 - Internal Control Processor."

What you feel. Sometimes nothing but a light. Often more. 🟢 The same FCA bulletin says "While the engine is running, customer may experience a vehicle limp in/home mode (speed limitation, engine throttle limitation and the ETC light flashing and MIL will be on) or the vehicle may experience a no-start condition." GM's 2018 Malibu paper prints "Crank no start or no crank condition with DTC P0606 and/or ten or more ECM related codes set." Among the owners who wrote to NHTSA the worst case is common: 2,215 of 4,032 complaints describe a stall, a loss of power or a limp mode, and 620 an engine that would not start, started hard or died soon after starting (complaints, not a failure rate).

What it is not. It is not a sensor code. A sensor code names a sensor; P0606 names a computer, and the computer may be reporting a fault it did not cause. 🟢 GM's 2017 bulletin for some Cruze, Express, Silverado, Savana and Sierra models says "The P0606 (ECM performance code) may set while cranking with a cam sensor fault present" instead of the cam sensor code, and prints "Important: Do Not replace the Engine Control Module (ECM) for this condition."

Is P0606 usually a dead engine computer, and does replacing it fix the car? PulsCar went through 4,655 complaints that name a control-module code or describe an engine or powertrain control module as failed, replaced or updated, each sorted twice by the same written rules: 4,032 on the owner's car, and only 26 print P0606. The module ends as the named or replaced part in 1,189 of the 4,032, and in 393 of those 1,189 the owner says the problem came back. These are complaints from owners who wrote to NHTSA, so they show how often owners say a replacement did not hold, not how often a computer fails. The documents are less module-centred: the printed causes include software, low voltage, a lost ground, an open cam sensor circuit, an oxygen sensor, aftermarket spark plugs, corroded connector pins and other modules. Test the battery, power and ground, then ask for the software status, before you buy the computer.

First: P0606, P0601, P0602, P0603, P0604, P0605 or P0607? One module, seven self-test labels

Read the exact code before you buy anything, because the same module family carries different labels, and the fix differs.

The counts are files in our set of 665 that print the plain code in their own text; counting suffix forms such as P060700 the totals are higher (P0607 176 files, 417 files for any of P0601 to P0607). More labels live next to these (P060A, P060B, P060C, P061A to P061E and P062F; not every one appears in the files): 168 files print at least one. They are processor and monitoring codes of the same kind, and Audi, Ford, Honda (for P061B), Mazda and Nissan print software or a wait for them, not a module, as the first answer; Honda's 2023-2024 Accord paper for P060A is the exception and prints a replaced PCM.

The maker atlas: who prints software, a voltage test, a connector, a different part or a computer

The same code means different things in different makers' papers. This is what each paper prints, vehicle by vehicle, in the words it uses.

General Motors prints the most, and says "software" first. 🟢 For 2016-2017 Cadillac ATS and CTS, Chevrolet Cruze and Malibu with stop/start: "The cause of the condition may be a software anomaly in the Engine Control Module," and "DO NOT replace the Engine Control Module at this time"; the reprogramming is covered for "8 years/80,000 miles (U.S.)". For the 2024 Traverse and Acadia: "Technicians may find DTC P0606 and/or P0607: Control Module Processor Performance", cause "a software issue", remedy "Reprogram the Powertrain Control Module (PCM)." For 2016-2018 Silverado, Tahoe, Suburban, Sierra, Yukon, Escalade and Malibu 1.5L: "Low voltage or a momentary loss of power or ground to the ECM may cause a DTC to set," with a test of every power and ground circuit before a module is replaced. For some 2017-2018 Cruze, Express, Silverado, Savana and Sierra: an open cam sensor circuit, and "Important: Do Not replace the Engine Control Module (ECM) for this condition."

GM also prints the real internal defects, by vehicle. 🟢 The 2018 Malibu 1.5L paper: "Cause: Internal issue with E88 Engine Control Module" and "If DTC P0606 is stored and/or 10 or more ECM related trouble codes are set, replace the Engine Control Module using latest parts available," with the note "This is a temporary repair and Engineering is working to root cause a permanent solution." A 2017 service update for about 500 Express, Silverado HD, Sonic, Trax, Savana and Sierra HD names "delamination on the electronic control module (ECM) printed circuit board (PCB) causing open circuits", and "Dealers are to replace and reprogram the ECM." A 2018 Malibu service update for dealer inventory "will expire February 28, 2019." GM's 2018 emissions recall 18239 replaces the module where "an electrical connection in the circuit board may fail", on an estimated "596 involved vehicles". Of these four GM papers only the Malibu paper names P0606; the 2017, the 2018 update and the recall describe a failed module and print a no-start, a stall or a check engine light.

P0606 on a GM truck can be the brake computer. 🟢 For the 2019 Silverado 1500 and Sierra 1500: "The EBCM incorrectly sets DTC P0606 indicating a Control Module Processor Performance error, when the root cause is a low voltage condition with the vehicles electrical system," and "If the SI diagnostics are followed for DTC P0606 it can lead to a misdiagnosis and an incorrect repair." The symptoms printed are a service-brake message, a speed limit and a hard brake pedal. For the 2024 Silverado and Sierra 2500HD and 3500HD: "Do not replace the Electronic Brake Control Module (EBCM) for this condition. Reprogram the EBCM." If a brake message, a speed limit or a hard pedal came with the code, have it towed (our advice, not a maker's rule).

Ford prints it for the transmission computer. 🟢 The 2011-2016 Fiesta and 2012-2016 Focus with the DPS6 automatic: P0606, with U0100, U0101 and U1013, "will be present or stored in the powertrain control module (PCM) memory," the remedy is to replace the TCM and reprogram, and the same paper says "This calibration installs DTC P0606; a new TCM internal failure code" and "Always resolve any vehicle low voltage concerns before replacing a TCM." In the complaint file, 11 of the 26 complaints that print P0606 are Fiesta or Focus.

Stellantis (FCA) prints software. 🟢 For the 2018 Dodge Durango SRT 6.4L: "CAUSE: PCM Software", "Associated with DTC: P0606 - Internal Control Processor," limp mode or no-start, remedy a PCM reprogram, "Reimbursable within the provisions of the warranty." The same words appear for the 2018 Grand Cherokee, and Alfa Romeo Giulia and Stelvio papers of February and March 2025 print "P0606 - Control Module Processor" with "PCM software". Its 2023 Renegade paper is the other face and names no P0606: "CAUSE: Powertrain Control Module (PCM) failure" with U0100-00 and a no-start, a new PCM, and "This RSU will expire 18 months after the date of issue."

Subaru prints the battery, and a wait. 🟢 For the 2014-2017 Forester Turbo and 2015-2017 WRX in the 2016 revision (the 2023 revision covers all models with the 2.0L and 2.4L turbo engines): "The engine management system is equipped with a back-up memory. When disconnecting the battery cables, this back-up memory is cleared," and if the ignition is turned back on within one minute the light can come on "storing DTC P0606 in memory."

Toyota and Nissan print software. 🟢 Toyota's April 2023 paper for the 2021-2023 Sienna Hybrid (P060694): "The hybrid vehicle control computer should NOT be replaced as part of the Repair Procedure," covered "for 96 months or 100,000 miles" from the in-service date. Nissan's paper for the 2017 Sentra with the MR16DDT turbo engine and manual transmission: "The MIL is ON with DTC P0606 (ECM) stored, and There are no drivability issues," with a reprogram.

Honda, Mazda, Toyota (older) and Audi print the cause around the module: aftermarket spark plugs, a corroded connector at the rear hatch, an oxygen sensor and a duplicate code. 🟢 Their words are quoted in Routes 3 and 4 below.

Volkswagen prints a code made by the update. 🟢 For 2022 Taos vehicles in the 24HV program: "In rare cases, a P0606 fault with symptom code 32902 may set after three key cycles after performing a software update," and the battery "must remain above 12.5 volts for the duration of the software update."

The do-not-replace lines: what the papers tell a shop not to buy first

Printed against replacing the module: GM's corporate bulletin (any module, before knowing which one set the code); GM 2016 ("Do not replace the ECM to correct this condition"); GM 2017 (cam sensor circuit); GM 2020 ("DO NOT replace the Engine Control Module at this time"); GM 2024 for the brake computer; Audi ("Do not replace the ECM", claims not reimbursed); Toyota (hybrid computer should not be replaced); Audi for a stored P0606 on the 2024-2025 SQ7 and SQ8: "Replacing the engine control unit is not necessary"; Audi prints "Do not replace any parts" for P060600 (P0606) on the Q4 e-tron; for the companion codes, Mazda (P061B), GM (P060C) and Volvo print the same words, Ford prints "Do not replace the PCM" (P061E) and Volkswagen an update first (P060C). For P0607, the closest cousin, Stellantis prints "DO NOT REPLACE THE PCM AT THIS TIME" on a paper for model-year 2017 vehicles, and for a 2026 Jeep Grand Cherokee a PCM is replaced only if the code resets after clearing (Route 2).

Printed for replacing it, on named vehicles only: the 2018 Malibu 1.5L ("temporary repair"), the 2017 trucks with delaminated boards, recall 18239, the 2021-2022 Renegade list, Honda's 2023-2024 Accord for P060A ("Replace the PCM if DTC P060A is stored."), GM's June 2026 brake-computer tips PIT6521 (replace the brake computer when it stores P0606 or P0607 and no other module has codes) and PIT6522 (replace it only if the concern remains after all diagnostics), GM's PIP5609 after a power and ground check, and Ford's DPS6 transmission computer. A P0606 on a car that is on no list is a car for which we found no paper telling a shop to replace its module for P0606; ask a dealer to check the VIN anyway, then test, update and decide.

The 10-minute check

1. Write down how it started and read the code (2 minutes). After a battery change, a jump-start, a software update, a wash or a flood, or on its own? Steady light, flashing light, or a message about brakes, steering or power? Read the code with a reader that shows maker codes and, if it can, which module reports it: an engine code and a brake or transmission code are different jobs. Do not clear it before the shop sees it unless you are about to test a fix (that is our advice, not a maker's rule).

2. Check the battery and its clamps (3 minutes). Are the terminals tight and clean, does the cable turn on the post, is the case swollen? 🟢 GM's brake-computer paper for the 2019 Silverado and Sierra asks first that the clamps are fully installed and tightened. A fully charged ordinary (non-AGM) battery rests near 12.6 volts by our battery-testing guide; a parts store often tests a battery for free. ⚪

3. Look at the module's plug and the wet places (2 minutes). The engine computer sits under the hood or inside the cabin depending on the car; a green or white crust on a plug, a smell of coolant, or a leak above it is the situation GM's papers describe behind a module plug (they list many codes, not P0606) and Mazda's paper describes at a connector in the rear hatch area. 🟢 GM's paper for the 2013-2019 ATS and 2014-2019 CTS says the module's connector terminals may be corroded "due to electrical fretting", and "Do NOT clean the terminals"; do not spray your own cleaner into a module's plug.

4. Find your VIN and paperwork (3 minutes). Ask a dealer whether a software update or a program exists for your VIN. Bulletins are dealer repair instructions, not recalls; ask the dealer for the terms of any program or recall on your VIN.

Six P0606 situations, and which is yours

"The light came on after a battery was disconnected or replaced." The cheapest cause is the battery or the wait. → Route 1.

"A steady light on a 2017 Sentra (Nissan prints no drivability issues), or P0606 on a 2020 Soul 1.6T or 2022-2024 BRZ." The papers print a reprogram. → Route 2.

"A 2019 Silverado or Sierra with a brake message, speed limit and P0606, or a 2024 2500HD or 3500HD." It can be the brake computer, with low voltage or a software diagnostic anomaly. → Routes 1 and 2, but tow it first if a brake message, a speed limit or a hard pedal is showing.

"A 2010-2012 CX-7 with P0606, or an ATS or CTS with intermittent stalling and no start, or a Cruze or Sonic with coolant in the module plug." A plug with moisture or fretting; Mazda prints it for a rear-hatch connector, GM for module plugs behind other codes. → Route 3.

"A 2006-2008 Civic with aftermarket plugs, a Toyota with oxygen-sensor codes, a 2017-2018 Cruze or Express that will not start and whose shop finds an open cam sensor circuit." A different part sets the code. → Route 4.

"A 2011-2016 Fiesta or 2012-2016 Focus with P0606 and U0100, a 2018 Malibu 1.5L with no-crank, a 2017 Express, Savana, Silverado HD, Sierra HD, Sonic or Trax whose VIN is on GM service update 17139, a 2021-2022 Renegade with a no-start." The papers print a replaced module on these vehicles; → Route 5; ask for the paper by number.

The P0606 price ladder, from the bottom up

The owner figures come from 236 complaints; 251 figures in all, of which 68 are described as paid, 69 as billed, 111 as quotes and three with no status. A quote is not a payment. The ranges are wide because the owners' vehicles run from 1999 to 2024 and the figures mix part, labor, parts markup and, in the "module plus" row, other repairs the owner folded into the same sum.

The five P0606 routes, cheapest first

Route 1 · The battery, the clamps, the power and the ground — $0 yourself, $100 to $350 for a battery

What it is. The module checks itself while it runs, and a low or dropping voltage, a momentary loss of power or ground, or a battery disconnected at the wrong moment can make the check fail. The fix is on the battery and the cables, not in the module.

What the documents say. 🟢 GM's 2018 paper: "Low voltage or a momentary loss of power or ground to the ECM may cause a DTC to set," with the instruction "Verify ALL controller power and ground supply circuits are correct. Repair if necessary," and "If NO power, ground or connection issues are present. Replace the ECM." GM's brake-computer paper for the 2019 Silverado and Sierra says the P0606 comes "when the root cause is a low voltage condition", and a second paper says that after a programming campaign "preliminary indications show that low battery voltage could be contributing". Subaru's turbo papers print the battery reconnect and a one-minute wait. Honda's older paper for 2001-2005 Civic: "the alternator can overcharge and fry the ECM/PCM," because of loose alternator bolts, and "any ECM/PCM damage caused by loose alternator bolts from A/C installation or body repair isn't covered by warranty." Volkswagen's tech tip: "The Battery Ground Cable must always be disconnected prior to the Battery Positive Cable. Failure to do so may result in internal ECM damage." Honda's and Volkswagen's papers describe a no-start and a module that does not answer, and name no P0606. Toyota's tech tip for some hybrids prints U010087 and a no-start rather than P0606: after a jump-start, "ECU damage may occur if the jumper cables are hooked up on or around the engine ECU or ECU mounting bracket."

What the owners report. 297 of the 4,032 complaints end at power, ground or wiring, and 108 of those 297 say the problem came back. The largest block is the alternator: 213 of the 4,032 complaints mention one, 116 of them end here, 155 are on Jeep, Dodge and Chrysler vehicles (mostly 2011-2013 Grand Cherokee and Durango), and many describe a computer lost with the alternator. One Grand Cherokee owner wrote that the shop "explained the alternator had fried and took the battery out with it" and then that the car needed a new powertrain control module, and put the bill at nearly $1,600; another wrote that after the alternator was replaced "the PCM was also fried" and "$2000 later I was back on the road." Counts are complaints, not cars.

The cheap cause that gets skipped. A battery terminal that looks tight and is not, or a battery too weak to hold voltage while the module wakes. A shop that reflashes or replaces the module on a weak battery risks the same code again; Nissan's flash paper prints "If the vehicle battery voltage goes below 12.0V or above 15.5V during reprogramming, the ECM may be damaged."

Fix it yourself. Check that both terminals are tight and clean, that the cable does not turn on the post and that the ground strap to the body is intact. Read the battery's resting voltage with a meter (how to test a car battery); a low reading is a reason for a parts-store test, which many stores run free. Do not spray cleaner into the module's plug. If the light and a charging warning come together, test the alternator before anything else: ⚪ our alternator guide puts a remanufactured alternator at an independent shop at $300-$650 for most cars, and a battery installed at $100-$350 in our battery guide.

At the shop — say this: "P0606 is stored. Before any module is replaced or reflashed, please test the battery and the charging system, check every power and ground circuit and the terminal tension, tell me which module set the code, and write the voltage on the repair order. GM's bulletins ask for the power and ground checks and the module's identity before a module, and Ford's asks to resolve low voltage before replacing the transmission computer."

Route 2 · A software update or reflash — free under a program, a median of $223.50, up to $1,600 reported

What it is. New software for the module that sets the code. In many papers it is the whole repair.

What the documents say. 🟢 GM, 2016 Onix, Spark and Astra: "Note: Do not replace the ECM to correct this condition." GM, 2016-2017 ATS, CTS, Cruze and Malibu: "DO NOT replace the Engine Control Module at this time. Follow the Service Procedure listed below to reprogram the ECM," and "DO NOT connect a battery charger." GM, 2024 Traverse and Acadia: "Reprogram the Powertrain Control Module (PCM)." FCA, 2018 Durango SRT and Grand Cherokee: "CAUSE: PCM Software." Kia, 2020 Soul 1.6T: an ECU upgrade event for P0606. Subaru, BRZ: "If DTC P0606 is stored in the ECM, perform the reprogramming procedures outlined in this bulletin." Nissan, 2017 Sentra: a reprogram, followed by throttle and idle relearns and a 10-minute drive. Toyota, Sienna Hybrid: a flash of the hybrid computer, with the battery tool "in Power Supply Mode to maintain battery voltage at 13.5V". The paper trail has a catch: 🟢 Volkswagen's 2022 Taos update prints "In rare cases, a P0606 fault with symptom code 32902 may set after three key cycles after performing a software update."

What the owners report. 828 of the 4,032 complaints end at a reflash, a relearn or a campaign procedure with no part named, and 508 of those 828 (61%) say the light, code or symptom came back or the repair did not hold, the highest share of any ending. One Silverado owner wrote that the update for the problem had been done "a couple weeks ago and it was suppose to fix this". Owners who report a price for it name $26.38 to $1,600 (paid, billed or quoted), a median of $223.50 across 26 figures; the 16 described as paid or billed have a median of $197.44. These are complaints from owners who wrote to NHTSA, so they show how often owners say a reflash did not hold, not how often a reflash works.

The cheap cause that gets skipped. A reflash done twice, because the first was done on a weak battery, or a code that was cleared and not re-tested. For one Stellantis case, a 2026 Jeep Grand Cherokee 2.0L with P0607, a bulletin prints "The technician is to clear the DTC. If the DTC does not reset after clearing, return the vehicle to the customer" and replaces the PCM only if the code resets. Our advice: once the shop has recorded the code, ask it to clear it and re-test before quoting a module; clearing it yourself and driving off is Trap 3.

Fix it yourself. You cannot, and should not try: a reflash on a bad battery or an interrupted power supply is a way modules are damaged.

At the shop — say this: "Is there a software update or a bulletin for P0606 on my VIN? Please check the module's software level, tell me the battery voltage you will hold during the update, and clear the code and re-test before you quote a module. If a bulletin applies, please write its number on the repair order."

Route 3 · The plug, water and corrosion at the module — no printed price for a plug; owners report $957.26 to $12,000 when liquid reached the module

What it is. A plug at the module, or a ground, whose pins are corroded, wet or oily, so that the module sees an intermittent supply or signal.

What the documents say. 🟢 Mazda, 2010-2012 CX-7 with the L5 engine: "This may be caused by corrosion on the C-31 connector due to moisture," repair "clean the connector using a commercially available electrical cleaner and inspect the area for source of a water leak," and, if it cannot be cleaned, replacement pins that may be available in the terminal repair kit. GM, 2013-2019 ATS and 2014-2019 CTS: "The ECM connectors X1, X2 and / or X3 may have more than one corroded terminal due to electrical fretting," and "Do NOT clean the terminals as you will NOT be able to clean the contact area and will have poor connections and set codes intermittently," and "If the ECM terminals inside the ECM socket have corrosion on them, the ECM must be replaced." GM, 2011-2018 Cruze and 2016-2018 Sonic with the 1.4L: "Coolant can wick up circuit 6814 ... get into connector causing bleed over or shorting of circuits." Neither GM paper lists P0606. Chrysler's 2015-2016 5.7L Hemi parts note for Ram trucks: when a module is being replaced "due to liquid being present inside of the PCM/ECM ... electrical connector(s)", the dealer is to call the named contact and, if no one answers within 15 minutes, continue with the repair; it names no P0606.

What the owners report. 88 of the 4,032 end at liquid or corrosion, and only 11 of those 88 say the problem came back, the lowest return share of any ending. They also include the dearest figures: a Subaru Ascent owner was quoted about $12,000, an Audi A8 owner $11,000 after the dealer found coolant in the harness and the module, and a Mercedes SL550 owner was billed $10,217; a Tundra owner reports a $3,855.95 bill after transmission fluid wicked through the harness into the computer.

The cheap cause that gets skipped. A leak above the module: a coolant reservoir or hose, a hatch seal. If the module is replaced and the leak is not found, the new module sits in the same water.

At the shop — say this: "Please pull the module's connector and look at the pins, the grounds and the area above for water or coolant before you quote a module. If you find moisture, show me, and write where it came from."

Route 4 · A different part sets P0606 — the price of the other part and the shop's diagnosis

What it is. The module fails its own check because another part upset it: a cam sensor circuit, an oxygen sensor, an interfering spark plug.

What the documents say. 🟢 GM, 2017-2018 Cruze, Express, Silverado, Savana and Sierra: "This condition may be caused by an open in the camshaft position sensor circuit," and "Once the P0606 is set, the crank is aborted and the cam sensor code is never set." Toyota, Avalon 2005-2010, Camry 2007-2010, Highlander 2008-2010, RAV4 2006-2010, Sienna 2007-2010 and Venza 2009-2010: P0606 may be present with P0138 or P0158 due to "incorrect Oxygen Sensor operation"; if the bank's second oxygen sensor fails the paper's voltage and impedance test and no harness fault is found, "replace the appropriate bank O2 Sensor ONLY to correct the P0606 DTC." Honda, 2006-2008 Civic: "Check for aftermarket spark plugs that include a built-in capacitor; they can cause electrical interference that can set this DTC," and "If the DTC doesn't come back, you've found the problem." Audi, 2.0 TFSI: P060600 stored with P023600 "without a good reason"; repair the first code, then erase the second.

What the owners report. 591 of the 4,032 end at a repair outside the module and its power and wiring, and 344 of those 591 say the problem came back. A further 90 end at a shop that found nothing or only cleared the code, and 37 of those 90 say it returned.

The cheap cause that gets skipped. The plugs. A previous owner or a quick-lube shop may have fitted a plug with a built-in capacitor, and on the Honda paper's vehicles that kind of plug can set P0606.

Fix it yourself. If your plugs are not the maker's type, change them back to the recommended ones, clear the code and, only if the car had been driving normally and nothing in the tow list applies, take a short trip and see whether the code returns; Honda prints exactly this test. If it had stalled, lost power, gone into limp mode, hesitated or surged badly, raced or would not idle down, failed to restart, shown a brake or steering warning or a flashing light, have it towed instead.

At the shop — say this: "P0606 is stored together with these other codes: [read them to the shop]. Please repair the other codes first, clear P0606 and re-test, and tell me if any paper by number says the module is not at fault."

Route 5 · The module itself, a transmission or brake computer, or a recall — a median of $1,300 reported, or free

What it is. The module has failed inside, or the maker names your vehicle on a list. This is the route the headline code scares people into on day one; the papers put it last.

What the documents say. 🟢 GM, 2018 Malibu 1.5L: "Cause: Internal issue with E88 Engine Control Module," with "temporary repair." GM, 2017 Express, Silverado HD, Sonic, Trax, Savana and Sierra HD (a no-start or stall, no code named): "Dealers are to replace and reprogram the ECM." GM recall 18239 (a check engine light, no code named): "Replace the Engine Control Module (ECM)", at no charge "regardless of mileage, age of vehicle, or ownership." FCA, 2021-2022 Renegade (the paper prints U0100-00 and U1701-87, not P0606): "CAUSE: Powertrain Control Module (PCM) failure", a new PCM, and "This RSU will expire 18 months after the date of issue." Honda, 2023-2024 Accord: "Replace the PCM if DTC P060A is stored." Ford, 2011-2016 Fiesta and 2012-2016 Focus: replace the TCM and reprogram. After a replacement the paper trail has warnings. 🟢 FCA, 2011-2014 Compass, Patriot, 200, Avenger and Journey and 2011-2012 Caliber with the 2.0L or 2.4L: "Updating the PCM software or replacing the PCM on a vehicle with an incorrect replacement engine will result in a no-start condition which can not be undone." GM, 2024 Traverse and Acadia: if a reprogramming is followed by a failed key provisioning, "it is not possible to recover the Powertrain Control Module (PCM) and it will need to be replaced."

What the owners report. 1,189 of the 4,032 end at a module named by a shop or replaced; 703 of them mention a stall or a limp mode and 235 a no-start; 393 of the 1,189 (33%) say the problem came back. One 2011 Malibu owner wrote that the dealer found "internal fault in engine control module P0606", replaced it, and on September 6 "same situation occurs on highway; complete power failure." A 2010 Savana owner reports a module at $344.01 and labor at $400.95. The owner figures for a module are $100 to $8,000, a median of $1,300 across 107 figures; the 49 described as paid or billed run $100 to $3,400.

The cheap cause that gets skipped. The battery and ground (Route 1), the update (Route 2) and the connector (Route 3) cost a fraction of a module, and the GM papers above put power, ground and a reprogram before a module. A replaced module that still shows the code means the cause may not have been the module, or that the new one is faulty or not programmed to the car: ask which test showed the module was at fault.

At the shop — say this: "Which module set P0606? Which paper or bulletin number says to replace it on my VIN? What did you test before you quoted a module — battery, power, ground, plug, software level? Is my VIN on a recall or a program? Is the new module programmed to my VIN, and what happens if the replacement does not clear the code?"

The coverage file: which programs and recalls run in September 2026

None of these programs covers the code in general; each is for a named vehicle and a named cause (20-NA-144 and some FCA bulletins name P0606 for their vehicles). "Status" is our computation from printed terms, as of September 2026.

The Ford recalls (19V075, 19V433, 24V444 and 26V237) are about a transmission that may downshift unexpectedly, and the fix is new PCM software; their filings and letters do not name P0606. Ford's 2026 filing covers 2015-2017 F-150 built March 12, 2014 to August 18, 2017 with the 6-speed automatic; for 2014 trucks, 24V444 says that if P0720, P0722, P0731 or P1500 is stored the leadframe is replaced too. One owner in the complaint file connects these recalls to P0606: a 2014 F-150 owner lists "P0606, P0607 (PCM Processor Faults)" beside 24V444. The owner letters for 24V444 and 26V237 say Ford has not issued instructions to stop driving.

Years and models in this table are as printed in the papers, the Part 573 filings and NHTSA's recall letters.

What 4,655 complaints about a control-module fault show

The complaint set is every complaint in NHTSA's file received from January 2015 to early October 2026 that names P0606 or a companion code in any spelling we searched, or describes an engine or powertrain control module as failed, faulty, diagnosed, damaged, replaced or updated in owners' words: 926 from the first search, 1,199 more from an independent check that found spellings and wordings the first search missed (such as "power train control module"), and 2,530 that name an engine computer only as replaced, updated or reprogrammed, which we first set aside and then added. Each was sorted twice, independently, by the same written rules; the two sortings matched on the main category in 87% (4,051 of 4,655), and the 1,074 complaints on which they differed on any point (604 of them on the main category) were settled by written rules; a last check of every complaint against its full text then corrected 773 of them. 4,032 describe a control-module fault on the owner's car; 623 do not. Counts are complaints, not cars, and nothing here is a failure rate.

What it looks like. 2,215 of the 4,032 describe a stall, a loss of power or a limp mode; 620 an engine that would not start, started hard or died after starting; 1,974 mention a recall, a campaign, a bulletin, a warranty extension or a "known issue". The 2011-2013 Grand Cherokee and Durango stand out for alternator failures that took the computer with them (Route 1); the Ford Escape and Edge for a computer named or replaced together with ignition coils (20 Escape and 42 Edge complaints mention coils); the F-150, the largest single model (332 complaints), for recalls and bulletins whose remedy is PCM software (240 involve a recall or bulletin).

The ending that holds best. Water and corrosion: 11 of 88 came back. The ending that holds worst. A reflash alone: 508 of 828.

The 2,530 complaints about a replaced or updated computer. These name an engine computer only as replaced, updated or reprogrammed. 2,193 of them describe a control-module event on the owner's car and 337 do not; 615 of the 2,193 end at a reflash alone (372 of those say it came back) and 585 at a module that was replaced or named. The two sortings agreed less often on this group (2,139 of 2,530, 85%), because an owner who writes "the PCM was updated" often does not say why.

The 26 complaints that print P0606

Only 26 of the 4,032 name P0606 themselves, and many of them are about another computer. Eleven are Ford Fiesta or Focus, the vehicles of the DPS6 transmission paper above (several of these owners name the transmission computer), four are 2019 Silverado 1500 (the brake-computer paper), and the other eleven are single vehicles: two Chevrolets, two Dodges, an Audi, a Mercedes, a Pontiac, a Ram, a Subaru, a GMC and a Ford F-150. By ending: 13 have no diagnosis or repair stated, 5 end at a repair outside the module, 3 at a module, 4 at a reflash and 1 at a shop that found nothing. Twelve describe a stall or a loss of power, two a no-start, sixteen a recall or bulletin, and five say it came back.

The four Silverado owners wrote almost the same thing: stored codes include P0606 and P25A2 with C0021, and the truck was limited in speed. GM's paper for that truck prints a brake-computer P0606 with a P25A2 in the engine computer; the fix is not an engine computer.

What owners say they paid

Owners put a dollar figure on 236 of the complaints (251 figures; 68 described as paid, 69 as billed, 111 as quotes and three with no status). Each figure is attributed to the module or its power, wiring or software, by one written rule; a sum that adds a transmission, engine-internal or tow bill to the module work is left out, a sum that names the module work together with smaller other work is kept in its own row, and every exclusion has a reason in our notes.

• Software or reprogramming (26 figures): $26.38 to $1,600, median $223.50.
• A replaced module (107 figures): $100 to $8,000, median $1,300; the top figures are quotes of $8,000 and $7,000. The paid or billed ones (49) run $100 to $3,400.
• A diagnostic fee (10 figures): $100 to $350 in 8 reports, and $600 and a $1,100 bill that included labor.
• A relay, pin or plug at the module (2 figures): $78 for an engine-computer relay and $1,000 for a PCM pin and a wiring check.
• The module fault repaired, parts not named (25 figures): $400 to $6,000, median $1,400.
• A module plus other work in one sum (81 figures): $100 to $12,000, median $2,400.

These are the owners' figures, not prices we verified.

Why P0606 comes back after a repair

Why does P0606 come back after a repair? PulsCar went through 4,655 complaints that name a control-module code or describe an engine or powertrain control module as failed, replaced or updated, each sorted twice by the same written rules. Of the 4,032 relevant ones, 1,625 say the same light, code or symptom came back, and the share depends on the ending: 61% after a reflash alone, 58% after a repair outside the module, 36% after a power, ground or wiring repair, 33% after a module, about one in eight after water or corrosion was found. The papers describe three situations that fit a return: a reflash or replacement done on a weak battery (Nissan, Toyota and VW print the voltage); a code set by another part (GM, Toyota, Honda, Audi), which returns until that part is fixed; and a module replaced when the cause was elsewhere. These are complaints from owners who wrote to NHTSA, not a measurement of how often repairs hold.

Can you drive with P0606?

Can you drive with P0606? It depends on what the car does with it, and none of the papers PulsCar went through tells an owner to stop driving. The closest is GM's brake-computer bulletin (a brake message, a hard pedal). Among 4,032 complaints (only 26 name P0606), 2,215 describe a stall or loss of power; a 2004 Dodge Ram 3500 owner wrote that the engine would not idle down and the brakes would only slow the truck; the shop found P0606. Our advice, not a maker's rule: a steady light on a car that drives and brakes normally can usually wait a few days for a diagnosis, on short trips; a stall, a loss of power, limp mode, bad hesitation or surging, racing or not idling down, a failed restart, even once, a brake or steering warning or a flashing light means tow it, because a car that stalls, loses power or fails to restart can do it again in traffic.

Should you buy a used car with a P0606 in its history?

Ask which module, and ask for the repair orders. A P0606 that a shop traced to a battery, a ground, a reflash or a plug and cleared, with the car driven since, is a different car from one with a replaced module that still shows the code. Check the battery and the charging system yourself, ask for the software level on the repair order, and run the VIN at nhtsa.gov/recalls. Walk away from a car whose seller cannot say which module set the code, or whose module was replaced twice.

Clearing P0606 before an inspection

Clearing the code does not fix it, and it also resets the car's readiness monitors, which an emissions inspection may check; GM's 2020 bulletin warns that clearing powertrain codes sets the inspection-and-maintenance status indicators to NO. Our advice: fix the cause, then clear it.

What the papers tell a shop to do with P0606, checkpoint by checkpoint

1. Which module set it. GM: "Do not replace any module before understanding which module has set the DTC, before following proper eSI diagnostics and until eSI diagnostics instruct to replace the module."
2. Voltage, power and ground. GM: "Verify ALL controller power and ground supply circuits are correct. Repair if necessary." Ford: "Always resolve any vehicle low voltage concerns before replacing a TCM."
3. Other codes first. GM's cam-sensor paper; Toyota's oxygen-sensor paper; Audi's P023600 overlap.
4. The software level. FCA and GM print a reprogram; Nissan, Toyota and Volkswagen print the battery voltage to hold.
5. The plug. Mazda and GM print the connector and its pins; GM prints "Do NOT clean the terminals".
6. Replace only where a paper says so, and then program it. GM, Honda and FCA name vehicles; FCA warns of a no-start if the engine's identification does not match the VIN.

Three P0606 traps

Trap 1: buying the engine computer for a code that sits in another module. On a 2019 Silverado it is the brake computer; on a Fiesta or Focus with the DPS6 it is the transmission computer; on a 2021-2023 Sienna Hybrid, Toyota prints the hybrid computer. Ask which module.

Trap 2: reflashing or replacing on a weak battery, or with the wrong engine. Nissan: "the ECM may be damaged" outside 12.0 to 15.5 volts. FCA (Route 5): a new PCM on a car with a replacement engine whose number does not match the VIN can cause a no-start that cannot be undone.

Trap 3: clearing the code and driving off. In the file, 37 of 90 complaints where a shop found nothing or only cleared the code say it came back.

Three composite scenarios

These are composite scenarios, not individual customers. They use only facts and price ranges on this page.

A 2019 Silverado with a speed limit and a brake message. The truck is towed in because of the brake message and the speed limit. The shop reads P0606 and a P25A2 and starts quoting a computer. The owner asks which module: the brake computer, and GM's paper for that truck asks first for the battery clamps and a voltage test. A tightened clamp or a battery cost $0 to $350; a reprogram is a dealer visit.

A 2012 Grand Cherokee whose battery light came on and that then would not start. The alternator was replaced, then the battery or the PCM. Two owners with a similar story put the bill at nearly $1,600 and about $2,000.

A 2018 Malibu 1.5L that will not crank, with P0606. GM's paper PIP5530 prints a replaced module on this vehicle, as a temporary repair, after a battery check. The dealer-inventory update 18017 expired on February 28, 2019. GM's emissions recall 18239 lists the 2018 Malibu only with the 2.0L engine, so a 1.5L car is not on it, but a dealer can still check the VIN for any open program.

The P0606 plan: 10 minutes, today, this week

Today (10 minutes). Read the code and the module that set it. Check the battery's terminals and voltage. Write down what happened before the light. Tow it if it stalled, lost power, went into limp mode, hesitated or surged badly, raced or would not idle down, failed to restart even once, came with a brake or steering warning or the check engine light is flashing.

This week. Ask a dealer for the software level and any bulletin or recall for your VIN. Test the battery and the charging system. Look at the plug and the wet places above the module.

Before anyone replaces a module. Ask which paper says so for your VIN, what was tested, and what happens if the code returns.

Sources and documents

Primary documents only. Where a claim in this guide is marked 🟢, it rests on one of the items below, and the reference is given so you can pull the document yourself. Claims marked ⚪ are shop-price estimates carried from PulsCar's repair guides — estimates, not measurements from a dataset we own.

1. General Motors: Service Bulletins 05-06-04-060A; 16-NA-180 Version 4 with Version 2 and Version 1; 17-NA-132; 20-NA-144; 24-NA-111 Version 2 and Version 1; 24-NA-050 Version 4; Preliminary Information PIP5609, PIP5530, PIP5790B and PIP5895; PIT5634, PIT5728 and PIT6169A; Service Updates 17139 and 18017; emissions recall 18239; PIP5463.
2. Ford: TSB 16-0044 and TSB 16-0129; SSM 47263; recalls 19V075, 19V433, 24V444 and 26V237.
3. Stellantis (FCA, Ram, Dodge, Jeep, Alfa Romeo): 18-083-23 and 18-084-23; 18-003-25 (and 18-018-25, P0607 only); 18-097-23; 18-058-19 Rev. A; 08-310-26; GPOP issue review of January 26, 2016 and tech tip 9003753; 18-002-14.
4. Subaru, Toyota, Honda, Mazda, Kia: Subaru 07-75-13R and 09-135-25; Toyota T-SB-0018-23, T-SB-0001-10 Rev1 and T-TT-0694-22; Honda A15120C, A15120F and Service Bulletin 25-025; Mazda SA-020/19 and P061B paper; Kia SA377 and P0605 paper; Hyundai P0605 letter.
5. Nissan, Audi, Volkswagen, Allison: Nissan NTB17-021, NTB25-013, Infiniti ITB16-008a, NTB17-063 and NTB17-065; Audi 2063394/1, 2079890/1 and recall 17V508; Volkswagen 24HV update revision 3, tech tip 01-19-05TT and P060C update paper; Allison P0602 paper.
6. PulsCar analysis of NHTSA public data, October 2026: 4,655 complaints about a control-module fault, each sorted twice by the same written rules; owner-reported amounts; the document list with check status and links. Complaints, amounts, documents, the sorting rules and how we did it are public under CC BY 4.0.

For the neighbouring pages: a check engine light that stays on, a car that starts and then dies, a car that stalls while driving, how to test a car battery and alternator replacement cost.

PulsCar does not diagnose a control-module fault from the sound of the engine. For P0606, the voltage at the battery, the stored codes and the documents above are the evidence.

Methodology. The complaint set is every complaint in NHTSA's file received from January 2015 to early October 2026 that names P0601 to P0607 (or P060A to P060C, P061A to P061E, P062F) in any spelling we searched, or describes an engine or powertrain control module as failed, faulty, diagnosed, damaged, replaced or updated in owners' words, in three batches: 926 from the first search, 1,199 more from an independent second search, and 2,530 more from that second search that name an engine computer only as replaced, updated or reprogrammed (we first set these aside, then added them; the rules for sorting them were fixed before they were sorted and are in the public file of rules): 4,655 in all. Every complaint was sorted twice, independently, by the same written rules; the two sortings matched on the main category in 4,051 of 4,655 (87%), and every disagreement was settled by a written rule. One reading, rule R35, was written down at the last check: a single repair that did not hold keeps its category and counts as came back; about 100 complaints that were settled earlier under rules R5 and R27 and are in "no cause named" with "came back" were not all re-sorted under the newer rule and may belong with the module, software, power or other-repair groups, because they state one failed repair; if they were moved, those groups would grow a little and the "no cause named" row would shrink, so read each share as approximate. Last, every complaint was checked again against its full text under the same rules, and that check corrected 773 of them (a category or a flag). A check of 100 complaints after that (40 from the first two searches, 40 from the added 2,530 and 20 marked not relevant) found a clear wrong category or flag in 2, 5 and 0 of them and 28 doubtful ones; read the shares as approximate, and those from the added complaints as the least certain. 4,032 describe a control-module fault on the owner's car and 623 do not. Counts are counts of complaints, not cars, and nothing here is a failure rate; the file holds the cases where owners wrote to NHTSA, not every car. The document set is every NHTSA index entry whose summary names one of the codes or discusses a control-module fault (499 listed, 441 with a PDF) plus 278 listed by the second search (223 with a PDF), and one extra file for a number that has two PDFs: 665 files, of which 579 are distinct once 86 exact copies are set aside. We went through 316 representative documents in full, compared the other 266 revisions and copies with them line by line, and checked 83 more files, for the codes and the module's name (18 whose text would not read were checked on page images). Model years, engines and build dates are as printed in the documents, never from NHTSA's index; recall years are from the recall filings and NHTSA's letters. Coverage status "as of September 2026" is our computation from printed terms. Amounts follow one written inclusion rule. The owner-reported amounts file lists every figure, and every exclusion has a reason in our notes.

Prices verified July to October 2026 in the repair guides they are carried from and in the owner reports above, and reviewed quarterly. Technical documents verified October 2026: the 579 distinct documents in our published file, of which 316 were read in full — among them Stellantis' 08-310-26 of August 2026; Subaru's 09-135-25 of May 2025 was compared line by line with its sister bulletin.

Had P0606 cleared by a battery, a ground, a plug, software or a recall, or a computer replaced for nothing? Email [email protected] with the vehicle, mileage and outcome.