GF27.10-P-3028AHT Key-P Function

GF27.10-P-3028AHT Key-P Function
- TRANSMISSION 722.931 in MODEL 221.074 /174, 216.374

Function requirements for Key-P in general

^ Circuit 15 ON

Key-P, general

The designation Key-P comprises all the functions which in addition to the parking brake serve to secure the vehicle to prevent it from rolling away unintentionally

Key-P function sequence

The function sequence is described in the following steps:
^ Park pawl function sequence
^ Ignition-lock lock function sequence
^ Function sequence for gear range "P" lock
^ Emergency-P function sequence (see document, Emergency-P function)

Park pawl function sequence

The park pawl only permits shifting out of selector lever position "P" by the gear selector switch DIRECT SELECT (S16/13) when the transmitter key (A8/1) is in position "circuit 15 ON" and the brake pedal is operated.

The "circuit 15 ON" signal is sent from the EZS control unit (N73) over the chassis CAN (CAN E) to the ME-SFI [ME] control unit (N3/10). The ME-SFI [ME] control unit forwards the status over the drive train CAN (CAN C) to the fully integrated transmission control unit (VGS) (Y3/8n4) and the intelligent servo module for DIRECT SELECT (A80).

In order to ensure that after parking the vehicle the intelligent servo module for DIRECT SELECT is automatically shifted to the gear selector switch position "P", the transmitter key can only be turned in this position towards "0" and then removed from the ignition lock.

The vehicle is secured mechanically by blocking the park pawl gear in the transmission.

With CODE (889) Keyless Go

On vehicles with Keyless Go, selector lever position "P" is engaged when the driver door is opened after the vehicle is parked.

The left rotary tumbler switch (A85s1) (on model 216) or the left front rotary tumbler switch (with model 221) sends the signal to the left door control unit (N69/1) (on model 216) or left front door control unit (with model 221). The left door control unit (with model 216) or the left front door control unit (with model 221) sends the status over the interior CAN (CAN B) and chassis CAN with the interface EZS control unit to the ME-SFI [ME] control unit. This then forwards the request to engage gear range "P" over the drive train CAN to the intelligent servo module for DIRECT SELECT.

Ignition-lock lock function sequence

The electronic ignition lock manually locks the transmitter key at a vehicle speed greater than 8 km/h.

It prevents the transmitter key from being removed because automatic engagement of selector lever position "P" cannot be performed by the intelligent servo module for DIRECT SELECT.

The transmitter key can be removed as long as the vehicle speed remains below the speed threshold and selector lever position "P" or "N" is automatically engaged by the intelligent servo module for DIRECT SELECT.

Selector lever position "P" lock function sequence

The selector lever remains locked in position "P" if the following conditions are not met:
- No power supply from intelligent servo module
- No enable from drive authorization system
- Brake pedal not actuated