Advanced Diagnostics

Advanced Diagnostics - DTC P0723: Output Shaft (Countershaft) Speed Sensor Intermittent Failure

General Description











The output shaft (countershaft) speed sensor is attached to the outside of the transmission housing. The output shaft (countershaft) speed sensor generates a pulsing signal according to the speed of the park gear on the output shaft (countershaft). Using that signal, the powertrain control module (PCM) determines the speed of the output shaft (countershaft). If pulse dropouts occur with the output shaft (countershaft) rotating, the PCM detects a malfunction that may be caused by an open, a temporary open, or a short to ground. Based on the fluctuation of the vehicle speed measured by the output shaft (countershaft) speed sensor, the PCM detects a malfunction and stores a DTC.

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






Enable Conditions






Malfunction Threshold
The fluctuation of the vehicle speed measured by the output shaft (countershaft) speed sensor [OUTPUT SHAFT (COUNTERSHAFT) SPEED] in 10 milliseconds is 4 mph (6 km/h) or more, and it fluctuates at least six times within 500 milliseconds.

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 line intermittent short to ground
- Output shaft (countershaft) speed sensor line intermittent open (includes connector loose connection or disconnection)
- Output shaft (countershaft) speed sensor intermittent failure
- PCM internal circuit failure

Confirmation Procedure

With the HDS
None.

With the Driving Pattern
1. Start the engine.
2. Drive the vehicle at a speed of 13 mph (20 km/h) or more until the transmission shifts into 5th gear.

- 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 during the first drive cycle, a Pending DTC is stored in the PCM 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.