Vacuum Supply, Function - GF42.22-P-1004KJE
MODEL 453.091/391/491 with ENGINE 780
Function requirements for vacuum supply in general
- Brake booster vacuum pump control unit (N65/3) activated
- Circuit 15 ON
Vacuum supply, general
The vacuum supply for the brake booster is supported by the electric vacuum pump (M56).
Vacuum supply function sequence
The brake booster vacuum pump control unit evaluates the signal from the brake booster vacuum sensor (B150/1), which measures the vacuum in the vacuum chamber of the BAS brake booster.
If the vacuum in the BAS brake booster is too low, the brake booster vacuum pump control unit actuates the electric vacuum pump.
As soon as the vacuum, measured by the brake booster vacuum sensor and assessed by the brake booster vacuum pump control unit, reaches the cutoff value, the electric vacuum pump is switched off.
The brake booster vacuum pump control unit regulates the electric vacuum pump on the basis of the brake booster vacuum sensor. The sensor value of the brake booster vacuum sensor is sent by the powertrain control unit via the LIN to the Electronic Stability Program control unit (N30/4). The Electronic Stability Program control unit evaluates the signal from the brake vacuum sensor (B64/1) which is also installed at the BAS brake booster. The Electronic Stability Program control unit performs a plausibility check on the value from the brake vacuum sensor using the value received from the brake booster vacuum sensor via the interior CAN. If the two sensor signals differ from each other, the fail boost function is activated in order to safeguard brake boosting.
Further information on the function sequence for the fail boost function can be found in the following document:
- Adaptive Brake (ABR), function
| Electrical function schematic for vacuum supply | PE42.22-P-2051-97BBE |