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Gear selector position sensor

Gear selector position sensor



The gear selector position sensor is mounted on the gearbox and consists of a double potentiometer connected by means of a shaft to the gearbox's selector shaft.

The sensor is supplied with 5 V from pin 10 of the control module and grounded from pin 35.

One of the sensor's potentiometers is connected to pin 27 of the control module and produces a voltage which changes as the gear lever is moved longitudinally.

The other potentiometer is connected to pin 28 of the control module and produces a voltage which changes as the gear lever is moved transversely.

By comparing the two voltages, the control module can identify the gear that has been selected. The voltages vary between 0.2 V and 4.8 V.


Important

The gear selector position sensor is highly sensitive and it is known from experience that many sensors are damaged in connection with their installation.


After replacement of the gear selector position sensor, gearbox or control module, the control module must memorize the new voltage combinations for each gear. This is done with the Scan tool diagnostics instrument, see .

Gear selector position sensor functions



1. On ignition switch-on, to permit opening of the clutch when the gear lever is in neutral or in reverse gear if the brake pedal is depressed at the same time.

2. To permit driving off in 1st, 2nd or reverse gear.


3. To determine in conjunction with the gear selector movement sensor whether the gear lever is moved into neutral or is already in a gear.


4. To prevent closing (engagement) of the clutch when the gear lever is in neutral.


5. To prevent the driver from leaving the car with a gear engaged.



If the gear selector position sensor is defective or in the event of a fault in the circuit, the "CHECK ACS" warning lamp will light up. The car can still be driven to a garage or repair shop but with reduced ease of clutch operation. The engine can be started whether or not a gear is engaged, provided that the brake pedal is depressed. The car can be driven off in any gear.

When the car is being driven, gear selector position sensor functions are substituted by the control module which compares the speed of the car with the speed of the gearbox's input shaft. If the shaft connected to the gear selector position sensor has worked loose in a gear which does now allow the car to be started or driven off, the gear selector position sensor can be disconnected. Thus will enable the car to be driven to a garage or repair shop.

Important

The safety functions are disconnected when a default function is activated.




Warning

If the car has to be driven with a defective or disconnected gear selector position sensor, the gear lever must always be put in neutral before the engine is started.