Range Rover (LM) V8-4398cc 4.4L (M62) (2003)
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Transmission Speed Sensor: Description and Operation
Turbine Shaft Speed Sensor
Description
The turbine shaft speed sensor is monitored by the TCM to calculate the slip of the TCC and internal clutch slip. This allows the TCM to accurately
control the slip timing during shifts and adjust clutch application or release pressure for overlap shift control.
The turbine shaft speed sensor is located in the main casing and secured with a screw. The sensor monitors turbine speed from a toothed target wheel on
the outer diameter of clutch 'B' housing. As the teeth of the target wheel pass the sensor tip, a change in the magnetic field of the sensor occurs and
generates an AC pulse in the sensor field winding. The pulse is passed on the negative (ground) wire to the TCM, which calculates the rotational speed.
The AC pulse generated is proportional to the rotational speed of the target wheel. The TCM measures the peak-to-peak outputs of the AC waveform to
calculate the rotational speed being measured.
There are two diagnostic checks on the turbine shaft speed sensor, a fault is detected if:-
1. The enabling conditions are satisfied and the turbine shaft speed sensor indicates a speed of 0 rpm.
2. The turbine shaft speed sensor indicates a speed of greater than 6800 rpm.
