Camshaft Position Sensor "A" Circuit Low (Bank 1 or Single Sensor)

Possible causes

• CommonFailed camshaft position sensor
• CommonCorroded or oil-contaminated connector at the sensor
• CommonStretched timing chain or a slipped timing belt - the sensor reporting a real problem
• CommonFailed variable valve timing actuator or a blocked oil control valve
• CommonLow or dirty engine oil, on engines with variable valve timing
• PossibleChafed or heat-damaged wiring
• PossibleDamaged reluctor or cam trigger wheel

What you might notice

• Long cranking before the engine starts
• Engine will not start
• Rough running or reduced power
• Poor fuel economy
• Rattle from the timing chain area on start-up
• Check engine light on

What to check, in order

1. Unplug the sensor and check whether the low reading persists at the harness.
2. Check the engine oil level and condition. On an engine with variable valve timing the cam actuators are oil-driven, so low or dirty oil produces camshaft timing codes with perfectly good sensors.
3. Inspect the connector for oil contamination and corrosion.
4. Check the wiring for chafe and heat damage.
5. Read all codes. Crankshaft codes alongside camshaft codes point at timing rather than at a sensor.