What Does It Mean?
This is a generic diagnostic trouble code (DTC) for the powertrain and generally applies to OBD-II vehicles. Vehicle brands may include, but are not limited to, Dodge, Chrysler, Ford, Chevrolet, Toyota, Honda, Nissan, etc.
The ECM (Engine Control Module) is not only responsible for monitoring and adjusting many sensors, solenoids, actuators, valves, etc., but also for ensuring that all these components work seamlessly and together to meet desired values. All this to ensure you get the most out of your vehicle’s fuel economy and performance. In this case, if you get a P0657 or a related code, depending on your make and model, you may experience transmission handling issues.
It is important to note that, in my experience with European models, I have also seen this code as an EVAP diagnostic code. After highlighting the potential differences, it goes without saying that you should refer to your service manual to ensure proper diagnostic direction. Most of the time, your symptoms will be a strong indicator of the systems/components you will be working with to correct the fault.
Regarding P0657 and related codes, the ECM has detected an abnormal value in the actuator supply voltage circuit. It recognizes the anomaly by comparing actual values to desired ones. If they fall outside the desired range, it illuminates the MIL (Malfunction Indicator Lamp) on your dashboard. It must monitor this fault for several drive cycles before turning on the MIL. Be sure to look for the “A” designation in the circuit. Depending on your make and model, this could designate a specific wire, harness, location, etc. That said, always use OEM (Original Equipment Manufacturer) technical service information for this.
This could also be detected by the TCM (Transmission Control Module) depending on the description your particular make and model have for this code.
P0657 (Actuator Supply Voltage Circuit A / Open) is active when the ECM or TCM has detected an open (or general malfunction) in the actuator “A” supply voltage circuit
P0657
How Severe Is This DTC?
The severity here is moderate, generally speaking. Since there are multiple code descriptions, you must exercise caution during diagnosis. Proper service data will be necessary. If this happens to be a transmission code in your case, you certainly want to repair it as soon as possible. Daily use of a vehicle with an active transmission code is a risk we do not want to take.
What Are Some of the Symptoms of the Code?
Symptoms of a P0657 diagnostic code may include:
Poor shifting
Lack of torque
Stuck in gear
CEL (Check Engine Light) illuminated
Overall poor driving
Limited output power
Poor fuel consumption
Abnormal engine speed/RPM
What Are Some Common Causes of the Code?
Causes
of this P0657 fault code may include:
Open/chafed wire
Water intrusion
Melted/broken connector(s)
Short to power
General electrical issue (e.g., charging system problem, bad battery, etc.)
What Are the Diagnostic and Troubleshooting Steps for P0657?
The first step in the troubleshooting process for any malfunction is to search Technical Service Bulletins (TSBs) for known issues with the specific vehicle.
Advanced diagnostic steps become very vehicle-specific and may require the appropriate advanced equipment and knowledge to operate accurately. We include the basic steps below but refer to a repair guide specific to the year/make/model/powertrain for steps tailored to your vehicle.
Basic Step #1
How you approach your diagnosis will depend on your make and model and the symptoms you are experiencing. But generally speaking, the first thing to do is clear the codes with your scanner and drive the vehicle until it becomes active again. If so, after locating the correct circuit/harness we are working with, inspect it for any damage. It might be routed under the vehicle where road debris, dirt, ice, etc., can damage the underlying circuits. Repair any open and/or chafed wires, if present. Additionally, it would be a good idea to inspect the involved connectors. You can disconnect them to inspect the pins for any that are bent or damaged and could cause electrical issues. Sometimes, high resistance in a circuit can cause excessive heat. To the point that it can burn through the insulation! That would be a good sign you have found your problem.
NOTE: Always solder and wrap damaged wires. Especially when they are exposed to the elements. Replace connectors with OEM ones to ensure proper electrical connections.
Basic Step #2
Locate your actuator using your service information. Sometimes these can be accessed from the outside. If that is the case for you, you can check the integrity of the actuator itself. The desired values involved in this test vary widely, but be sure to have your mu