Use the instrument cluster diagnostic mode (click here for how
) to see if the vehicle speed is displayed in the odometer. If it is the output shaft speed (OSS) sensor is OK, if not then it is bad or there is a wiring problem.
The speedometer "gauge" is a stepper motor driven by the instrument cluster microcontroller, based on data packets sent by the PCM. Using the cluster diag mode bypasses the gauge driver routines and hardware, and displays the PCM's digital data on the odometer.
An alternative would be to use an OBD2 data logging tool and monitor the vehicle speed PID, again if it reads correctly the OSS is OK...
- 2003 GT, UPR X, FRPP 24lb/h, Magnaflow, PP 70mm TB & plenum, Delta Force tuned,
Steeda UDPs, Ralco flywheel, RAM HDX clutch, 3.73s, 262 rwHP/305 lb-ft.
New ride (7/1/2013) 1998 Mercedes SL500-5.0L 32V VVT 326/347 HP/tq