P0657 means Actuator Supply Voltage A Circuit/Open. The computer has lost or cannot confirm the supply voltage it sends to a group of actuators such as solenoids and relays. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0657 means
Modern vehicles have many control modules that share information over a network, usually called the CAN bus. Codes starting with U mean a module has stopped hearing another one, and voltage and processor codes mean a module is not getting clean power or has an internal fault. Low battery voltage, poor grounds, blown fuses and damaged wiring cause many of these codes, so test the battery and charging system first.
P0657 symptoms
- Check engine light
- Several systems acting up at once, such as shifting, cooling fans or cam timing
- Possible limp mode
Common causes of P0657
- A shorted actuator on the shared supply circuit
- Damaged wiring or connector
- Blown fuse or failed relay
- Module fault (less common)
How to diagnose P0657
- Read all codes; other actuator codes point to the one at fault
- Check the related fuse and relay
- Unplug actuators on the circuit one at a time to find a short
- Check battery and charging voltage
Can you drive with P0657?
Depends on what is affected; get it checked soon.
P0657 tips
One shorted solenoid or relay can pull down the shared supply; unplug them one at a time to find it.
Will P0657 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0657 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0562 | System Voltage Low |
| P0563 | System Voltage High |
| P0606 | Control Module Processor |
Guides that help
When it is more than a sensor
Voltage and network codes come from wiring, the battery, the charging system or a module, not from engine or transmission wear. If a lost-communication code has left the transmission in limp mode, rule out the module and wiring before deciding the unit has failed, and see our transmissions only if testing confirms internal damage.
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