P0657 OBD-II Trouble Code: Actuator Supply Voltage “A” Circuit/Open

Our certified mechanics come to you · Get a fair and transparent estimate upfront


Cost of diagnosing the P0657 code

P0657 is a diagnostic trouble code (DTC) for "Actuator Supply Voltage “A” Circuit/Open". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
SCHEDULE P0657 DIAGNOSTIC Get a fair and transparent estimate upfront

P0657 code definition

When the PCM or one of the control modules that support and feed into it (e.g., the fuel control module, antilock brake control module, body control module, etc.) detects a fault in the supply voltage to the “A” circuit, the P0657 code will be stored, and the Check Engine light will be illuminated.

What the P0657 code means

The PCM and the vehicles other control modules are constantly performing self-checks and self-monitoring to ensure that the PCM is functioning efficiently and properly. The PCM does this through checks of output signals, internal circuits, and checks on its internal memory status. If there’s a malfunction during this monitoring process, the PCM will store the P0657 code after a predetermined number of drive cycles. Some vehicles will require up to eight cycles of malfunctions, while others will require fewer.

What causes the P0657 code?

The most common causes of a P0657 code include:

  • An open or shorted circuit in the PCM
  • An open or shorted circuit between two interfacing supporting control modules
  • An open or shorted circuit between the engine sensors and the PCM
  • A disconnected ground wire running to a control module
  • An internal malfunction within the PCM

What are the symptoms of the P0657 code?

When a P0657 code is stored, you can expect the following symptoms:

  • The Check Engine light will illuminate.
  • The engine may be difficult to start or may not start at all.
  • The engine may run rough at idle or while driving at speed.
  • The engine may misfire and/or have a lack of power, especially when accelerating.

How does a mechanic diagnose the P0657 code?

When diagnosing a P0657 code, a mechanic will first use an OBD-II scanner to identify the code and any other codes that may be related to it. They will then perform a visual inspection of any affected circuits to look for damaged, corroded, or loose wires or connectors.

If they do not see any damage to the circuit(s), they will likely use an ohmmeter to test the circuit(s) for shorts or open connections. Once they find the cause of the problem, they’ll diagnose and fix it, and then they’ll retest the system to ensure that the code is not stored again.

Common mistakes when diagnosing the P0657 code

When a P0657 code is stored, other codes may also be stored and symptoms may occur as a result of the breakdown in internal communication due to the open or shorted circuit. Resolving these symptoms will not solve the underlying problem, which is the open or shorted circuit. So, if other codes are found in relation to a P0657 code, you will almost always want to deal with the P0657 code first.

How serious is the P0657 code?

Though it may not have severe symptoms of its own, a P0657 code can cause other problems in the engine due to a malfunction within the PCM or one of its circuits. In addition to a rough riding engine, this can lead to a number of other potentially severe and dangerous problems. Thus, it’s important to get your P0657 code diagnosed and resolved ASAP.

What repairs can fix the P0657 code?

Though the problem causing this code will almost always be a shorted or open circuit, there are a few different repairs that may fix it, including:

  • Securing and tightening PCM connectors and/or ground wires.
  • Repairing or replacing the PCM wiring harness.
  • Reprogramming the PCM.
  • Replacing the PCM.

Additional comments for consideration regarding the P0657 code

Even if your vehicle seems to be running smoothly with a stored P0657 code, if you need to get an OBD-II emissions test performed in order to renew your registration, you will need to address the problem and clear the code. If the code is stored at the time of your emissions test, it will illuminate the Check Engine light, which will make your vehicle ineligible to pass.

Need help with a P0657 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0657 code.

Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

YourMechanic Check Engine Light is on Inspection Service

Average Rating


Number of Reviews


Rating Summary


7 years of experience
6 reviews
7 years of experience
Kia Sedona - Check Engine Light is on - Pittsburgh, Pennsylvania
Kenneth is clearly a first-rate mechanic. He thoroughly inspected our vehicle and found that the engine light was on because of a crack in the filler neck hose.


10 years of experience
731 reviews
10 years of experience
Jeep Wrangler - Check Engine Light is on - Arlington Heights, Illinois
This is my first time using Your Mechanic. Rigoberto arrived earlier than the appointment time. He was very knowledgeable, helpful and answered all my questions.


14 years of experience
48 reviews
14 years of experience
Hyundai Sonata - Check Engine Light is on - Bellerose, New York
Jason was a pleasure to work with. He went above and beyond on my car and it was very much appreciated. Jason worked on my car for 4 days and he was very professional and punctual. He educated me on the health of my car. He was fair and flexible with his quotes. I highly recommend Jason and will be utilizing his services again.


5 years of experience
45 reviews
5 years of experience
Ford F-150 - Check Engine Light is on - Alameda, California
show up on time, great guy, very knowledge on what he's doing, would recommend his work to everyone, keep up the good work thank you.

More related articles

Related questions

The P0010 error keep coming up and my car keeps jumping, and turning itself off and on while I drive sometimes.

Hello, thanks for writing in. If you took your vehicle in for repairs, and it was returned with a check engine light then I would immediately return to the shop and have them take care of the issue. If the...

Throttle body position sensor

The rumbling noise may be coming from the loose catalyst in the exhaust piping. It would need to be verified by a road test to listen to the noise. If the catalyst is breaking up in the exhaust then the...

Misfire and P0420

Hello - the P0420 and the inconsistent waveform for the post-cat O2 sensor might be related to your failing intake manifold gasket issue. If tiny droplets of coolant are being sucked into the engine - one failure mode for this...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com