Component Tests and General Diagnostics

Checking the supply voltage/ground terminal

Voltage feed Park Brake Module (PBM)
Park Brake Module (PBM) is supplied with voltage via two voltage inputs on the control module.
1. Power input 1 terminal #C1:13 (#13) is supplied with +30 via a fuse in the rear relay/fusebox (RJB) from the battery. The input also supplies voltage to right brake caliper. In case of open circuit, the right brake caliper will not be activated.
2. Power input 2 terminal #C1:15 (#15) is supplied with +30 via a fuse in the rear relay/fusebox (RJB) from the battery. The input also supplies voltage to left brake caliper. In case of open circuit, the left brake caliper will not be activated.

Checking the power supply
Check the voltage feed cable from the battery to Park Brake Module (PBM) #C1:13 (#13) and #C1:15 (#15) for open circuit, loose connection, contact resistance and oxidation. Check the fuse. The voltage must be approximately battery voltage.

Ground connection Park Brake Module (PBM)
Park Brake Module (PBM) has two ground inputs. Both ground inputs from the control module are connected via two separate ground leads to the same ground connection in the body. See the relevant wiring diagram for further information about the ground terminal.
- Ground input 1, #C1:28 (#28) is power ground and is connected to the ground connection in the body.
- Ground input 2, #C1:30 (#30) is power ground and is connected to the ground connection in the body.

Checking the ground terminal
Check the ground cables between Park Brake Module (PBM) #C1:28 (#28), #C1:30 (#30) and ground connection for open circuit, loose connection, contact resistance and oxidation. At ignition on, the voltage-drop between Park Brake Module (PBM) ground connection and chassis connection may not be greater than 0.5 V.
Remedy as necessary.

Other information
- Connecting the breakout box Connecting the Breakout Box, Parking Brake Module (PBM)
- Signal specification Signal Description, Parking Brake Module (PBM)
- See the relevant wiring diagram for information about circuits and ground terminals in the bodywork.
- Checking wiring and terminals Checking Wiring and Terminals

Troubleshooting procedure complete

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