Ignition Spare
The ignition system has a spare or redundant circuit that the ECU monitors for proper operation, similar to a backup generator ensuring power continuity. When this spare ignition circuit fails to respond as expected, the ECU logs this code to alert you of potential ignition reliability issues.
The ECU monitors the spare ignition circuit's voltage, timing signals, and switching integrity during engine operation. It compares the redundant ignition path against expected parameters to ensure backup ignition capability is available. If the circuit voltage or response time falls outside acceptable thresholds, the fault is logged.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Spare Ignition Circuit Voltage | 12-14V (engine running) | <10V or >15V |
| Circuit Response Time | <10ms switching response | >25ms or no response |
Code P1371 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, P1371 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.