Gear Shift Lock Solenoid Circuit High
The transmission's shift lock solenoid circuit is receiving too much electrical voltage, preventing the system from properly locking or unlocking the gear shifter. Think of it like a door lock that's getting too much electrical power and can't respond correctly to open or close.
The ECM monitors the voltage signal sent to the gear shift lock solenoid, which should fall within a normal operating range. When voltage remains consistently above the expected threshold, the ECM detects a circuit high condition and triggers the fault code. This typically indicates excessive voltage, a short to power, or solenoid resistance failure.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Solenoid Control Voltage | 0.5–4.5V (varies by vehicle) | >5.0V or continuous max voltage |
| Circuit Resistance | 20–50 ohms | Open circuit or very low resistance |
Code P0931 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0931 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.