P0657 Actuator supply voltage circuit open or out of range: the module that powers the engine and throttle actuators sees a problem with their supply

Actuator supply voltage circuit/open

P0657 in short

P0657 means the engine computer sees a problem in the voltage supplied to its actuators, such as the throttle motor. On 2015-2016 Acura TLX and MDX it comes with the car shifting into neutral while driving. Wiring, low battery voltage, a relay or the module itself can cause it, so get it checked soon.

The computer powers actuators such as the electronic throttle through a supply circuit and watches it. P0657 sets when that supply is open or out of range. TroubleCodes.net notes that manufacturers use the code differently, so the vehicle manual matters.

Acura service bulletin PU B15-034 describes a 2015 TLX and 2016 MDX that shifts into neutral while driving, shows the transmission indicator and stores P0657, and the driver cannot select a gear until the car is turned off and restarted. A TLX owner says the dealer updated the transmission control module, PGM-FI and ABS software.

Mitsubishi tells dealers to replace the throttle actuator control (TAC) relay when P0657 and other codes appear in extremely cold weather on Outlander, Outlander Sport and Mirage. TroubleCodes.net lists wiring faults, low battery voltage, voltage spikes and water in modules as general causes.

Most likely causes

  1. Damaged wiring or connectors, or low battery voltage

    Common general cause
    Why it ranks here
    TroubleCodes.net lists burnt, shorted or corroded wiring and connectors, voltage spikes and low battery voltage first.
    What would change this
    Rises if the battery is weak or a connector is corroded or wet. Falls if supply and wiring test good.

  2. Control module software (2015 TLX, 2016 MDX)

    Supported by vehicle data
    Why it ranks here
    Acura PU B15-034 describes the shift into neutral with P0657; a TLX owner says the dealer updated the transmission control module, PGM-FI and ABS software. The summary of the bulletin does not state the repair.
    What would change this
    Rises if the car shifts into neutral on a listed model. Falls if it is another vehicle or the symptom is absent.
    How to test the transmission control module (tcm)

  3. Throttle actuator control (TAC) relay in extreme cold (Mitsubishi)

    Supported by vehicle data
    Why it ranks here
    Mitsubishi TIN-18-13-001 says to replace the TAC relay for stored codes including P0657 in extremely cold weather.
    What would change this
    Rises if it appears only in extreme cold on an Outlander, Outlander Sport or Mirage. Falls in mild weather or on other makes.

  4. Water in a module or a failed control module

    Possible — needs testing
    Why it ranks here
    TroubleCodes.net lists water in modules and, rarely, a failed control module.
    What would change this
    Rises if wiring, power and software are ruled out. Falls if any other cause is found.
    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. Read all codes and freeze-frame data. Note whether the vehicle lost drive or shifted into neutral and whether the weather was extremely cold.

    Low riskTool: OBD-II scan tool

    • IfThe vehicle shifted into neutral while driving

      It meansGet it to a dealer and ask about the bulletin.

      Go to step 3

    • IfIt happened in extreme cold on a Mitsubishi

      It meansAsk about the TAC relay bulletin.

      Go to step 3

    • IfThe code is pending with no symptoms

      It meansTest the battery and wiring.

      Go to step 2

  2. Have the battery, charging voltage, grounds and the actuator supply wiring and connectors tested.

    Low riskTool: battery tester, multimeter

  3. Ask a dealer whether your VIN has an open bulletin for P0657.

    Best left to a shop

    Warning:This needs specialist tools and vehicle service information. Leave it to a shop.

Symptoms

  • Check engine light on
  • Vehicle shifts into neutral while driving Gets more serious: stop and have it checked.
  • Reduced power or limp mode Gets more serious: stop and have it checked.
  • No symptoms, pending code only

How to fix

  1. Have the battery tested.

On your vehicle

Acura

  • 2015 · TLX

    Supported by vehicle data

    Acura PU B15-034 ties P0657 to a shift into neutral while driving; an owner says the dealer updated transmission, PGM-FI and ABS software. Whether the bulletin is still current is not verified.

  • 2016–2019 · MDX

    Supported by vehicle data

    Acura PU B15-034 ties P0657 to a shift into neutral on the 2016 MDX; a 2019 owner quotes the same wording.

  • PU B15-034Status unverified

    Shifts into neutral while driving with P0657

    2015–2016mdx, tlx · NHTSA 10107357

    The vehicle shifts into neutral, the transmission indicator lights and P0657 is stored; the driver cannot select a gear until the vehicle is restarted.

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

Mitsubishi

  • 2014–2018 · Outlander

    Supported by vehicle data

    Mitsubishi TIN-18-13-001 replaces the TAC relay for P0657 in extreme cold. Whether the bulletin is still current is not verified.

  • TIN-18-13-001Status unverified

    DTCs including P0657 in extremely cold weather

    2013–2018outlander, outlander-sport, mirage · NHTSA 10133197

    Dealers replace the throttle actuator control (TAC) relay.

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

No curated relationships for P0657 yet.

All Engine computer (ECM/PCM) codes

P0657 questions

Why did my Acura shift into neutral with P0657?

Acura documents this on the 2015 TLX and 2016 MDX. Have a dealer check for the service bulletin and software updates.

Sources and review

  1. P0657 trouble code overview — TroubleCodes.net
  2. Acura service bulletin PU B15-034 (NHTSA 10107357): shifts into neutral with P0657 on 2015 TLX and 2016 MDX — American Honda Motor Co.
  3. NHTSA complaint ODI 11505092: Acura TLX 2015, dealer found P0657 actuator supply voltage circuit/open — NHTSA Office of Defects Investigation
  4. Mitsubishi TIN-18-13-001 (NHTSA 10133197): DTCs including P0657 in extreme cold — Mitsubishi Motors
  5. NHTSA complaint ODI 11442525: Acura MDX 2019, shifts into neutral with P0657 — NHTSA Office of Defects Investigation
Last reviewed
Written by
Saurabh K.
Editorial review
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