Brakes and Traction Control: Description and Operation

4602 - Diagnosis

All components such as sensors, magnetic valves and the return pump and all functions are constantly monitored by the control unit. This way, for example, the return pump can also repeatedly be activated for short periods when driving or the pressure sensor can send test signals to the control unit when the vehicle is stationary.

If the fault detection is activated, the PSM is not shut down completely after a fault evaluation. Instead, certain systems are retained if the relevant signals are still available.

Example:
If the yaw velocity sensor fails, only the vehicle dynamic control is deactivated. ABS and EBD remain active. If a wheel sensor fails at the same time, ABS will also be deactivated. EBD still remains active.

Faults are entered into the fault memory where they remain permanently stored. The fault memory can be read out and deleted via the PIWIS Tester. Further functions such as controlling the drive links, inputs and system tests are also carried out.