LR3/Disco 3
A gear position sensor, located on top of the front housing, is used to enable the transfer box to determine which gear the
transmission is in. This information is used for both instrumentation and range change functions.
The transfer box control module receives a gear position signal and publishes the status on the CAN bus. The selected
gear is shown in the information display of the instrument cluster. The transfer box also uses the status message to check
the vehicle is in neutral before attempting a range change.
The gear position sensor is a Permanent Linear Contact less Displacement (PLCD) type sensor. It uses the 'X' axis as the
left and right position of the lever and the 'Y' axis as the forward and backward position. The sensor gives a voltage in 'X'
and 'Y' directions, which is used to deduce the gear position.
The PLCD sensor uses the electromagnetic induction principle, which has a primary winding around a soft magnetic core.
On each end of the core is a second short coil winding and when a permanent magnet is in the vicinity of the sensor, the
core is interrupted at that point and two separate transformers are created. Each transformer generates an induced
voltage in the secondary coils. The induced voltage of 0 to 5 V in turn provides proportional feedback to the transfer box
control module relative to the position of the magnet assembly.
SPEED SENSOR
Item Part Number
Description
1
-
Sensor body
2
-
Magnet assembly
