Transmission Position Sensor/Switch: Service and Repair

Transmission Park Selector Switch

Transmission Park Selector Switch (F305) consists of two microswitches. The two microswitches create the signal that the electronic ignition key removal lock needs to release the key only in selector lever position P.

The first microswitch is closed when the Shift Lock Solenoid (N110) is not active in selector lever position "P" (with brake pedal not depressed) and also selector lever manual release below ashtray is not actuated.

The second microswitch is closed when the button on selector lever handle is not actuated in selector lever position "P".

Following points must be observed before replacing Transmission Park Selector Switch (F305):

1. Both microswitches are switched electrically in sequence, that is, both switches must be closed for ignition key to be removed. Microswitches can be checked using Vehicle Diagnosis, Testing and Information System (VAS 5051A) in Guided Fault Finding. After performing tests on vehicle system, you must select test program "F305 - Gear selector position P switch" via function/component selection (drive/automatic transmission/01-On Board Diagnostic (OBD) capable systems/02 - Transmission Electronics/Electrical components).

2. An electrical test on the microswitch is also possible. If a continuity test is performed with a multimeter, note that in this case, there is a resistance value of approx. 470 Ohm when both switches are closed.

Removing

- Remove selector mechanism function unit => [ Selector Mechanism Unit ] Selector Mechanism Unit.

- Remove shift gate => [ Shift Gate ] Shift Gate

- Pry out retaining pins - A - with a screwdriver in direction of - arrow -.





- Remove first microswitch - B - forward.

- Disengage electrical wiring from tab - arrow C - and remove microswitch from shift mechanism.

- Release connector - D - and remove from Shift Lock Solenoid (N110).





- Release connector - E - and remove upward.

- Press tab - C - in direction - arrow 1 -.

- Remove second microswitch - B - in direction - arrow 2 -.

- Disengage electrical line at selector mechanism - arrow A -.

Installing

Install in reverse order of removal, note the following:

• Lubricate bearing areas and slide surfaces with polycarbamide grease (G 052 142 A2).

- Guide microswitch on longer electrical line into opening under parking lock button in selector mechanism.

- Guide shift gate - 1 - from below.





• Shift gate selector lever in "S" position (as shown in illustration).

- Insert microswitch - B - in shift gate and secure it with retaining pins - A -.

• Microswitch must lie flush on all sides.

- Engage electrical line in tab - arrow C -.

• Retaining screws - A - secure microswitch - B - in shift gate.

• Ignition key removal lock does not function correctly if microswitch is not inserted correctly or properly secured.

- Secure electrical line - arrow A - at selector mechanism according to illustration.





- Install microswitch - B -.

• Ignition key removal lock does not function correctly if microswitch is not inserted correctly or properly secured.

- Position connector - D - on Shift Lock Solenoid (N110).

- Engage connector - E - from above.

- Install shift gate => [ Shift Gate ] Shift Gate

- Install shift mechanism function unit => [ Selector Mechanism Unit ] Selector Mechanism Unit.