GF27.10-P-2008AHI Shift-Lock, Function
GF27.10-P-2008AHI Shift-lock, function
- TRANSMISSION 722.930
Function requirements, Shift-Lock, general
^ Circuit 15 ON
^ Brake pedal operated
^ Vehicle speed > 8 km/h
Shift-Lock, general
The term shift lock combines the functions which, in addition to the parking brake, offer an additional safeguard for the vehicle to prevent it moving off unintentionally.
Shift-Lock, function sequence
The function sequence is subdivided into the following steps:
^ Park pawl
^ Locking ignition switch
^ Locking of selector lever position "P"
^ Shift-Lock override (manual release of selector lever position "P")
Park pawl (except code 889 KEYLESS-GO)
The park pawl can only be shifted out of selector lever position "P" when the ignition key (transmitter key (A8/1)) switches the ignition ON and the brake pedal is operated.
In order to ensure that after parking the vehicle the selector lever is shifted into selector lever position "P", the transmitter key can only be removed from the EIS control unit (N73) in this position. The vehicle is secured mechanically by blocking the park pawl gear in the transmission.
Selector lever position "P" can be released manually (Shift-Lock override) in the event of mechanical or electrical faults.
Park pawl (with code 889 KEYLESS-GO)
The park pawl can only be shifted out of selector lever position "P" when the ignition is switched ON via the KEYLESS-GO start-stop button (S2/3) and the brake pedal is pressed.
The vehicle can only be parked via the KEYLESS-GO start-stop button when the selector lever is engaged in selector lever position "P".
Locking ignition switch
The mechanical components of the ignition lock lock connects the selector lever of the center shifter console with the EIS control unit. It prevents the transmitter key from being removed when selector lever position "P" is not engaged.
The EIS control unit locks the transmitter key mechanically when the ignition is ON and at a vehicle speed >8 km/h.
As soon as the vehicle speed of 8 km/h is exceeded, the EIS control unit prevents the removal of the transmitter key, as the automatic engagement of selector lever position "P" cannot be performed by the electronic selector lever module control unit (N 15/5).
The transmitter key can be removed as long as the vehicle speed remains under the speed threshold. In the process the selector lever position "P" is shifted automatically by the electronic selector lever module control unit.
Locking of selector lever position "P"
The selector lever remains locked in position "P" if the following conditions are not met:
- No power supply from the electronic selector lever module control unit
- No enable signal from the drive authorization system (DAS 3)
- Brake pedal not actuated
Upon receipt of a valid drive authorization code from the EIS control unit and a brake detection from the ESP, SPS [PML] and BAS control unit (N47-5) via engine compartment CAN (CAN C) the electronic selector lever module actuates the locking solenoid for the reverse/park pawl (Y66/1).
The locking solenoid enables the selector lever and thus makes possible a shift out of selector position "P".
Component Identification:
Should it not be possible to engage a gear range from selector lever position "P" for reason of mechanical or electrical faults, the lock of selector lever position "P" can be released manually. To do this, the stowage compartment in the center console must be unclipped and, using a suitable tool, the guide located underneath pressed onto the lever (arrow). The selector lever position "P" lock is released via a bolt in the lock solenoid valve. When the lever and selector lever are operated simultaneously the selector lever can be shifted out of selector lever position "P".
