Meaning

The engine control module has detected that the crankshaft position (CKP) sensor signal is consistently below the expected minimum threshold. The circuit exhibits insufficient voltage or signal amplitude, indicating a short to ground, an open, or a sensor failure.

Common causes

• CKP sensor signal wire shorted to ground
• Faulty CKP sensor with degraded voltage output
• Open circuit in sensor wiring or corroded connectors
• Excessive air gap between sensor and reluctor wheel
• Severely worn reluctor wheel or covered by ferromagnetic deposits
• Sensor supply voltage or ground problem

Symptoms

• Check-engine light (MIL) illuminated
• No-start or hard-start condition
• Total loss of RPM signal on the instrument cluster
• Engine stalls while running
• Injection and ignition disabled by the ECM

Severity

What to do

1. Measure voltage and resistance at the CKP sensor connector with engine running and at rest
2. Check for short to ground on the signal wire
3. Verify wiring continuity from ECM to sensor
4. Inspect the connector for oxidation, pushed-back pins, or physical damage
5. Replace the CKP sensor and retest; if the fault persists, check the ECM

Format conversion