Gear Shift Lock Solenoid Circuit Range/Performance
The transmission's gear shift lock solenoid isn't working properly—it's the electronic lock that prevents you from shifting out of Park without pressing the brake. Think of it like a door lock that's stuck or not responding when you try to open it.
The ECM monitors the solenoid coil resistance and current draw when energized. It expects a specific voltage drop and current signature; if the circuit reads out of range—too high resistance, low current, or abnormal voltage response—the fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Solenoid Coil Resistance | 10–30 ohms | <5 ohms or >50 ohms |
| Control Circuit Voltage | 12–14V when active | <8V or >16V |
Code P0929 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, P0929 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.