Gear Shift Lock Solenoid Circuit High Voltage
The P0931 code indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the gear shift lock solenoid/actuator control circuit. This solenoid prevents the shift lever from moving out of Park unless the brake pedal is pressed. A high voltage reading suggests a short to power, a faulty solenoid, or a wiring issue. This can cause the shift lock to malfunction, potentially preventing the vehicle from shifting out of Park or allowing shifting without brake application.
1. Symptoms You Will Notice
- Unable to shift out of Park
- Shift lever moves out of Park without brake pedal pressed
- Check Engine Light illuminated
- Brake lights may not function properly
2. Most Common Causes
- Short to power in the shift lock solenoid circuit
- Faulty shift lock solenoid/actuator
- Damaged wiring or connector in the shift lock circuit
- Faulty brake pedal position sensor or switch
- PCM internal failure (rare)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P0931 is present. Check for other related codes.
Step 2: Inspect the shift lock solenoid wiring and connector for damage, corrosion, or shorts.
Step 3: Test the shift lock solenoid resistance and compare to manufacturer specs.
Step 4: Check the brake pedal position sensor/switch operation and circuit.
Step 5: If all else is okay, test the PCM output to the solenoid circuit.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The shift lock may fail, causing the vehicle to shift out of Park unexpectedly or preventing shifting altogether, which can be a safety hazard.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor, but could be higher if the PCM needs replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.