P1391 Chevrolet Wheel Speed Sensor 1, G-Sensor Circuit Performance

Possible causes

– Timing belt or chain stretched or jumped
– Faulty Camshaft Position (CMP) Sensor
– Camshaft Position (CMP) Sensor harness is open or shorted
– Camshaft Position (CMP) Sensor circuit poor electrical connection.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1391 Chevrolet Description

The ECM detected the actual Camshaft Position Sensor (CMP) position disagreed with the expected CMP level.