P0601 Control module internal memory checksum error

Engine computer memory error

P0601 in short

P0601 means a control module, usually the engine computer, found that its stored memory failed an internal checksum test. Check battery, power and ground connections first, then look for a software update or reprogramming. Replace the module only if the code returns after that. Get it diagnosed soon, and stop if the engine cuts out.

Control modules check their own memory by adding up the stored data and comparing the result with a value saved alongside it. If the two do not match, the program or calibration may be damaged, and P0601 sets.

GM's service information runs this test continuously with the ignition on, and sets it on an internal fault or incomplete or incorrect programming. Its repair path is to clear the code, reprogram the module and replace it only if the code comes back.

On GM vehicles, the same code can be stored by the transmission or fuel pump module, so the shop needs to know which module set it before replacing anything.

Most likely causes

  1. Poor power, ground or battery connection to the module

    Supported by vehicle data
    Why it ranks here
    GM tells dealers to inspect the engine computer's connections, powers and grounds before replacing it for P0601-P0604. Owners report a bad battery cable and harness corrosion from a water leak behind this code.
    What would change this
    Rises with a weak battery, loose or corroded battery cables or ground straps, or water damage near the module or harness.
    How to test the engine control module (ecm / pcm)

  2. Software or programming problem (update available)

    Supported by vehicle data
    Why it ranks here
    Incorrect or incomplete programming is one of GM's set conditions, and Mazda, Volkswagen and FCA all have bulletins that clear P0601 with a software update.
    What would change this
    Rises after recent programming, a failed update, or when a bulletin covers your vehicle.
    How to test the engine control module (ecm / pcm)

  3. Code set by a different module (GM)

    Supported by vehicle data
    Why it ranks here
    GM warns that P0601 can be stored in the transmission or fuel pump control module as well as the engine computer, so the wrong module can be replaced.
    What would change this
    Rises if a scan tool shows the code under the TCM or another module rather than the ECM.

  4. Failed control module

    Common general cause
    Why it ranks here
    An internal fault in the module sets the code directly. GM's procedure replaces the module only when the code returns after reprogramming, so it ranks after the checks above.
    What would change this
    Rises if the code returns immediately after a correct reprogram with good power and grounds.
    How to test the engine control module (ecm / pcm)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Check the battery state of charge and inspect both battery cables and the visible engine ground straps for looseness and corrosion.

    Low riskTool: battery tester or multimeter

  2. Use a scan tool that reads all modules to see which one stored P0601, and note any other codes such as P0602 or P0630.

    Low riskTool: full-system scan tool

  3. Have a dealer or equipped shop check for bulletins and reprogram the module with the latest software, then clear the code and retest.

    Best left to a shopTool: manufacturer programming tool, stable battery maintainer

    Warning:An interrupted or wrong program can leave the module unable to start the engine. Leave programming to a shop with a stable power supply.

Symptoms

  • Check engine light
  • Often no other symptom
  • Reduced engine power Gets more serious: stop and have it checked.
  • Engine shuts off while driving Gets more serious: stop and have it checked.

Compare with: Check engine light with loss of power

How to fix

  1. Write down every stored code, and which module stored it, before clearing anything.

  2. Clean and tighten the battery terminals and make sure the battery is fully charged before any reprogramming.

Parts and cost context

  • Engine control module (ECM / PCM):A replacement engine computer usually has to be programmed to the vehicle, and GM replaces it only after reprogramming fails to clear the code.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Chevrolet

  • 2016–2018 · Silverado 1500

    Supported by vehicle data

    GM tells dealers to check the engine computer's connectors, powers and grounds for P0601 before replacing it (PIP5609).

  • 2016–2018 · Malibu

    Supported by vehicle data

    GM tells dealers to check the engine computer's connectors, powers and grounds for P0601 before replacing it (PIP5609).

  • PIP5609Status unverified

    GM PIP5609: P0601-P0604 and related ECM codes

    2016–2018silverado-1500, tahoe, suburban, malibu · issued · NHTSA 10151817

    Inspect the engine computer's connections, powers and grounds; replace the ECM only if nothing else is found. Also lists GMC Sierra 1500 and Yukon and Cadillac Escalade.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

GMC

  • 2016–2018 · Sierra 1500

    Supported by vehicle data

    GM tells dealers to check the engine computer's connectors, powers and grounds for P0601 before replacing it (PIP5609).

  • PIP5609Status unverified

    GM PIP5609: P0601-P0604 and related ECM codes

    2016–2018silverado-1500, tahoe, suburban, malibu · issued · NHTSA 10151817

    Inspect the engine computer's connections, powers and grounds; replace the ECM only if nothing else is found. Also lists GMC Sierra 1500 and Yukon and Cadillac Escalade.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mazda

  • 2013 · MX-5

    Supported by vehicle data

    Mazda changes the PCM logic for P0601:00 that sets after decelerating in first gear (SB-01-018-13).

  • SB-01-018-13Status unverified

    Mazda SB-01-018-13: P0601:00 after deceleration in first gear

    2013mx-5 · issued · NHTSA 10053731

    On the 2013 MX-5, the MIL can come on with P0601:00 just after decelerating in first gear; the PCM logic is changed.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ram

  • 2022 · ProMaster 1500

    Supported by vehicle data

    FCA has a PCM update for P0601 'Internal Memory Checksum Invalid' on the 2022 ProMaster.

  • 1802522 REV CStatus unverified

    FCA PCM updates: P0601 internal memory checksum invalid

    2022promaster-1500, promaster-2500, promaster-3500 · issued · NHTSA 10226024

    2022 Ram ProMaster PCM reprogram for P0601 and P0325, with adaptive cruise or remote start possibly inoperative.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Volkswagen

  • 2006–2007 · Jetta

    Supported by vehicle data

    Volkswagen has a programming update to eliminate a stored P0601 on 2006-2007 models (TB011417).

  • TB011417Status unverified

    VW TB011417: programming update to eliminate P0601

    2006–2007jetta, golf, passat · issued · NHTSA 10241320

    Update programming to eliminate P0601 stored in memory on 2006-2007 Volkswagen models; NHTSA also lists Beetle, GTI, Eos and others.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P0606A control module found a fault in its own processor or programming

    Same system Supported by vehicle data

    P0606 is the module's processor self-test fault. GM groups it with P0601 in the same diagnostic, and both can set together.

  • P0607A control module failed one of its internal performance checks

    Same system Supported by vehicle data

    P0607 is another control module performance fault in the same GM diagnostic.

All Engine computer (ECM/PCM) codes

P0601 questions

Does P0601 mean I need a new engine computer?

Not necessarily. GM's procedure is to check power and grounds, then reprogram, and replace the module only if the code comes back. Several makers fix P0601 with a software update.

Sources and review

  1. 2011 Saab 9-4X V6 (GM): DTC P0601-P0607, P0610, P062B, P062F, P0630, P16F3 or P2610 (ECM) — General Motors / Saab Automobile (read via saabwisonline.com)
  2. GM PIP5609: P0601-P0604 and related ECM codes, check powers and grounds — General Motors / NHTSA ,
  3. GM bulletin 05-06-04-060A: control module DTCs P0601–P0606, P062F, P06F3, P1621 shared across modules — General Motors / NHTSA ,
  4. NHTSA complaint ODI 10535149: 2006 Chevrolet Trailblazer, P0601 with engine shutting down while driving — NHTSA Office of Defects Investigation (complaint flat file) ,
  5. NHTSA complaint ODI 10538232: 2009 Chevrolet Impala, P0601 with reduced power then shut-off on the interstate — NHTSA Office of Defects Investigation (complaint flat file) ,
  6. NHTSA complaint ODI 11374791: 2005 Pontiac G6, P0601/P0606 with harness corrosion from sunroof leak — NHTSA Office of Defects Investigation (complaint flat file) ,
  7. NHTSA complaint ODI 11023837: 2013 Chevrolet Suburban, P0601, engine died on highway, bad battery cable — NHTSA Office of Defects Investigation (complaint flat file) ,
  8. Mazda SB-01-018-13: 2013 MX-5 P0601:00 after deceleration in first gear — Mazda North American Operations / NHTSA ,
  9. Volkswagen TB011417: update programming to eliminate P0601 — Volkswagen of America / NHTSA ,
  10. FCA bulletin 1802522 REV C: PCM updates, P0325/P0601 — FCA US / NHTSA ,
  11. GM PIP4653B: P0601/P0603/P0604/P062F/P1621 stored in the TCM — General Motors / NHTSA ,
Last reviewed
Written by
Saurabh K.
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