Skip to content
Skip to content

OBD-II Code

P0657

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$250–$2,000

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

$250 (throttle body DIY with TSB-covered platform discount) to $2,000 (ECM replacement + programming + throttle body when isolation goes wrong).

P0657 means the PCM detected the Actuator Supply Voltage A circuit either open or out of range — this is the dedicated power feed the PCM uses to supply electronic actuators (electronic throttle body, EGR motor, intake-manifold runner control, turbo wastegate solenoid, and similar high-current loads).

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

  1. Note every code that is set, not just this one.

    Codes that appear together usually narrow the cause faster than any one of them read alone.

  2. Read the freeze frame — the conditions the fault was recorded under.

    Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.

  3. Confirm the fault is current rather than history.

    Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.

  4. Then follow the diagnostic notes further down this page, in the order they are written.

    They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

  • Check engine light
Read the full diagnostic procedureP0657 means the PCM detected the Actuator Supply Voltage A circuit either open or out of range — this is the dedicated power feed the PCM uses to sup…

P0657 means the PCM detected the Actuator Supply Voltage A circuit either open or out of range — this is the dedicated power feed the PCM uses to supply electronic actuators (electronic throttle body, EGR motor, intake-manifold runner control, turbo wastegate solenoid, and similar high-current loads). Depending on platform, the rail is regulated to either 5V (low-current actuator logic) or switched battery voltage (10-14V, high-current actuator power). On VW/Audi TSI/TDI and GM E67 ECM platforms specifically the rail powers the electronic throttle motor — a fault here will set the throttle into limp-home mode immediately.

Shop-floor ladder, cheapest first

  1. identify which actuators are on Supply A from the FSM. With KOEO, backprobe the supply wire at each actuator connector; you should read either steady 5V (regulated) or battery voltage (switched) depending on platform.
  2. If supply reads 0V at every actuator, the rail is open between the PCM and the first device — wiring or PCM internal driver.
  3. If supply reads correct at some actuators but low or 0V at others, the open or short is between the last good and first bad.
  4. Disconnect each Supply-A actuator one at a time and watch the rail; the actuator that, when removed, lets the rail return to spec is the loader.
  5. Expensive-misdiagnosis caveat: P0657 on VW/Audi will almost always be the throttle body itself (internal short pulling the supply down) rather than the ECM — VW even has TSB coverage on the electronic throttle for specific MY ranges.
  6. Don't quote an ECM until the throttle body is disconnected and Supply A measured with the throttle isolated; a $400 throttle masquerading as a $1,500 ECM job is the worst kind of misdiagnosis.
Vehicle-specific patterns2008-2014 VW/Audi 2.0T TSI (GTI, A4, Passat, Tiguan) and 2.0L TDI commonly throws P0657 from electronic throttle body internal shorts — the throttle…
  • 2008-2014VW/Audi 2.0T TSI (GTI, A4, Passat, Tiguan) and 2.0L TDI commonly throws P0657 from electronic throttle body internal shorts — the throttle motor draws excess current as the brushes wear and pulls the actuator supply rail down; the fix is a new throttle assembly with adaptation reset via VCDS.
  • 2010-2015GM LS3 / L99 / LSA / LT1 with the E67 ECM (Camaro SS, CTS-V, Corvette) throws P0657 from throttle body motor failure or from harness chafing at the throttle connector where the supply wire runs adjacent to the heat shield.
  • 2009-2013Audi 3.0T supercharged V6 (S4, S5, Q5) throws P0657 from intake-manifold-runner actuator internal shorts loading the Supply A rail.
  • 2007-2012GM 3.6L direct-injection V6 throws P0657 from throttle body or EGR position actuator failures.

Estimated repair$250 (throttle body DIY with TSB-covered platform discount) to $2,000 (ECM replacement + programming + throttle body when isolation goes wrong).

Look up another code

More free tools

VIN DecoderDecode year, make, model, engine, recalls.Maintenance ScheduleOil, timing belt, fluids, by vehicle.Tire SizeOEM vs new — diameter delta + speedo error.Gas CostWeekly, monthly, annual fuel math.

See all 9 tools