Output Shaft Speed Sensor
The vehicle speed sensor is located within the gearbox. The TCM uses this sensor to monitor the rotational speed of the parking gear and to translate this reading into a vehicle speed. The TCM also monitors the vehicle speed using a signal from the ABS Control Module (CM). The vehicle speed sensor detects the parking gear rotation speed and sends an electrical output to the TCM, which also provides an earth path for the sensor. The sensor is an inductive sensor that produces a sinusoidal output at a frequency of 18 pulses per revolution of the parking gear. The TCM calculates the equivalent vehicle speed based on the current selected gear ratio, the turbine speed sensor frequency and the intermediate speed sensor frequency, in comparison with the measured vehicle speed sensor frequency to determine correct operation. In the event of a discrepancy the TCM uses a calculated vehicle speed based on the remaining functional speed sensors.
At 2004MY the intermediate shaft speed sensor was deleted, therefore from 2004MY onwards the output shaft speed sensor diagnostic is now based on vehicle speed.
In both instances a rationality test is used to detect a fault condition. A fault is present if a minimum or maximum shaft speed threshold (up to 2003MY) or vehicle speed threshold (2004MY Onwards) is exceeded.
If the appropriate table does not include details of the following enabling conditions: intake air and engine coolant temperature, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor. See Fig 1 or Fig 2 .