Meaning

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

Common causes

• CMP sensor signal wire shorted to ground
• Faulty CMP sensor with degraded voltage output
• Open circuit in sensor wiring or corroded connector
• Excessive air gap between sensor and camshaft reluctor wheel
• Sensor supply voltage (typically 5 V or 12 V) or ground fault
• Camshaft reluctor wheel covered by ferromagnetic deposits

Symptoms

• Check-engine light (MIL) illuminated
• Hard or extended cranking start
• Engine runs in batch (non-sequential) injection mode with reduced performance
• Rough idle or misfires
• Possible increase in fuel consumption

Severity

What to do

1. Measure supply and signal voltage at the CMP connector with the engine running
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 damage
5. Replace the CMP sensor if wiring is found serviceable

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