P0720

Advanced Diagnostics

Advanced Diagnostics - DTC P0720: Output Shaft (Countershaft) Speed Sensor Circuit Malfunction M/T Model)







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

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 at 3,000 rpm without load (in neutral) until the radiator fan comes on.
2. Drive the vehicle at engine speed 2,000 - 3,000 rpm for several minutes.
3. Decelerate with the throttle fully closed for at least 8 seconds.
* Drive the vehicle in this manner only if the regulations and ambient conditions allow.

Diagnosis Details

Conditions for illuminating the MIL
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the ECM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and freeze frame data are stored in the ECM memory.

Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.