Possible causes

– Faulty Speed Sensor
– 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

P0721 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.

P0721 Information for specific makes

P0721 ACURA
P0721 AUDI
P0721 BMW
P0721 CHRYSLER
P0721 DODGE
P0721 FORD
P0721 HONDA
P0721 HYUNDAI
P0721 JEEP
P0721 KIA
P0721 MAZDA
P0721 MITSUBISHI
P0721 SUZUKI
P0721 VOLKSWAGEN