What it means
The gear shift lock solenoid/actuator control circuit A reports a control circuit a high condition. Selector lever interlock cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
How it works
Circuit A controls the gear-shift lock solenoid or actuator that helps prevent the selector leaving Park until release conditions are met. P0931 means the module detects circuit A voltage higher than expected, often because the wire is shorted to battery voltage or the actuator coil is open.
Common causes
Most likely first.
- Control wire shorted to B+
- Open coil
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Save freeze-frame data and scan for related shift-lock or transmission codes.
- Check selector operation with the brake pressed and note whether the interlock releases consistently.
- Inspect circuit A wiring and connectors for damaged insulation touching a power feed, loose terminals, or an open connection.
- Use a scan tool to observe or command circuit A while operating the selector, if supported.
- Test the circuit for a short to battery voltage and check the actuator coil for an open against the manufacturer's specification.
- If the readings vary, move the harness while monitoring circuit A to identify an intermittent fault.
Common fixes
- Repair circuit A wiring shorted to a power feed.
- Secure or repair a loose or damaged circuit A connector.
- Replace the circuit A actuator if its coil is open.
Can I keep driving?
If the selector cannot be moved or secured reliably, do not drive. If it operates normally, limit driving and stop if the interlock or gear selection becomes unreliable.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.