Parking assist system and/or brake booster electronics problem?

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New member
Aug 25, 2022
Hello fellow Bolters,

For some time now, I have had "Service Park Assist System" appear on the display when I put the car in reverse or when the driving speed drops below 6mph or so. The assistance systems do not work, there are no sounds. Cleaning/checking the sensors did nothing. Rear camera with guidelines works fine.

There are no DTCs logged (checked with 2 different OBD2 devices).

Yesterday I went to the dealer, he connected his GM MDI 2 scanner, the result was a bit baffling:

The sensors are all fine, but the scanner reports that it can't communicate with the the brake booster module. The technician thinks it's related, but I'd have to make an appointment and leave the car at the shop for 1-2 days to get an accurate diagnosis.

It all seems strange to me.... The fuses are all ok and the brake booster control module can certainly communicate with other modules via the vehicle network - as soon as it or the brake pedal sensor are disconnected the car throws the corresponding DTCs, which can then also be cleared via the OBD interface when the module is reconnected.

A workshop visit of several hours just to hear that the brake booster ($1000+) needs to be replaced doesn't really sound that appealing to me, maybe someone has some experience or another idea?