Advanced Diagnostics

Advanced Diagnostics - DTC P0720: Output Shaft (Countershaft) Speed Sensor Circuit Malfunction (Engine Type: R18Z1)

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 for 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 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 [ENGINE SPEED] at 4,000 rpm or less.

Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

- Output shaft (countershaft) speed sensor NC line short to ground
- Output shaft (countershaft) speed sensor NC line open
- Output shaft (countershaft) speed sensor connector disconnection
- Output shaft (countershaft) speed sensor defection
- ECM internal circuit failure

Diagnosis Details

Conditions for setting the DTC
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 the freeze data are stored.

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.