Emergency-P function - GF27.10-P-3029ACS
TRANSMISSION 722.649 in MODEL 216.3 as of model year 2009/modification year 08
TRANSMISSION 722.649 in MODEL 221.1 as of model year 2009/modification year 08
Function requirements for Emergency-P, general
- Emergency motor supply voltage
Emergency-P, general
In emergencies, if e.g. undervoltage prevails in the on-board electrical system or the communication with the intelligent servo module for DIRECT SELECT (A80) is faulty, the emergency motor in the intelligent servo module for DIRECT SELECT is supplied with power from the onboard electrical system battery via the EIS [EZS] control unit (N73) (G1) and thus triggers the emergency-P function.
As of 1.9.08 with the eccentric shaft driven by the emergency motor the gearwheel drive is replaced by a belt drive.
Emergency-P function sequence
The function sequence is subdivided into the following steps:
- Start position function sequence
- Intermediate position function sequence
- End position function sequence
- Function sequence cancellation
Start position function sequence
Start position, shown up to 31.8.08
The emergency motor is supplied with power by the on-board electrical system battery via the EIS [EZS} control unit in an emergency, e.g. with undervoltage in the on-board electrical system, and turns the eccentric shaft.
Intermediate position function sequence
Intermediate position, shown up to 31.8.08
The rotating eccentric shaft presses down onto the release studs of the left carriage half. This in turn causes the mechanical connection between the left and right carriage halves to be broken.
End position function sequence
End position, shown up to 31.8.08
The pre-compressed coil spring pushes the two carriage halves apart. The right carriage half slides along the threaded spindle to the right and pushes the range selector lever to position "P". The eccentric shaft continues to rotate, until the emergency motor is no longer actuated. The actual position of the eccentric shaft is recorded by the eccentric shaft position sensor.
Function sequence cancellation
If undervoltage is no longer present in the on-board electrical system, the Emergency-P function is deactivated and the intelligent servo module for DIRECT SELECT reverts to its normal operating condition.
The main motor drives the threaded spindle by way of the drive pinion gears. The left carriage half runs on to the right carriage half, the coil spring is pre-compressed again and the mechanical connection made again.
The Emergency-P function cannot be overridden manually.
| Component description for intelligent servo module for DIRECT SELECT | A80 | GF27.19-P-4020ACS |