Advanced Diagnostics

Advanced Diagnostics - DTC P0720: Output Shaft (Countershaft) Speed Sensor Circuit Malfunction






General Description
The output shaft (countershaft) speed sensor is attached to the transmission housing to sense output shaft (countershaft) revolutions. The powertrain control module (PCM) determines the vehicle speed according to the signal from the output shaft (countershaft) speed sensor for the control units. If no signal from the output shaft (countershaft) speed sensor is received for a set time, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
No signal from the output shaft (countershaft) speed sensor is detected for at least 5 seconds during deceleration with the engine speed at 4,000 rpm or less.

Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on.
2. Drive the vehicle at engine speed 2,000 - 4,500 rpm for several minutes.
3. Decelerate with the throttle fully closed for at least 5 seconds.

- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.