P0721 Chevrolet Output Speed Sensor Range/Performance
Possible causes
– Faulty Speed Sensor
– Speed Sensor harness is open or shorted
– Speed Sensor circuit poor electrical connection
– Speed Sensor harness is open or shorted
– Speed Sensor circuit poor electrical connection
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Speedometer improper reading
– Possible shifting problems
– Speedometer improper reading
– Possible shifting problems
P0721 Chevrolet Description
The speed sensor detects the revolution of the idler gear parking pawl lock gear and emits a pulse signal. The pulse signal is sent to the Transmission Control Module (TCM) which converts it into vehicle speed.