Component Tests and General Diagnostics

Checking the supply voltage/ground terminal

Checking the power supply and ground terminals

Power supply, Subwoofer module (SUB)
The subwoofer module (SUB) is powered via a power input on the control module.
When the ignition is on, the power input is powered and the subwoofer module (SUB) is in active mode.
- Power input 1 (terminal #53 (#A3)) is powered via a fuse from the central electronic module (CEM). The subwoofer module (SUB) will not be activated if there is an open-circuit.

Checking power supply
Check the power supply cable from the battery to the central electronic module (CEM) and from the central electronic module (CEM) to the subwoofer module (SUB) terminal #53 (#A3). Check for an open-circuit. Check for loose connections. Check for contact resistance. Check for oxidation. Check the fuse. The voltage must be approximately battery voltage when the ignition is on.

Ground terminal, subwoofer module (SUB)
the subwoofer module (SUB) has a ground input. The ground input from the control module is connected via a ground lead to the ground terminal in the car body. See the relevant wiring diagram for further information about ground terminals.
- Ground input 1 (terminal #51 (#A1) is power ground and is connected to the ground terminal in the car body.

Checking ground terminal
Check the ground lead between subwoofer module (SUB) terminal #51 (#A1) and the ground terminal. Check for an open-circuit. Check for loose connections. Check for contact resistance. Check for oxidation. With the ignition on, the drop in voltage between the ground connection for the subwoofer module (SUB) and the ground terminal must not be greater than 0.5 V.
Remedy as necessary.

Other information
- Connecting breakout box Connecting the Breakout Box, Subwoofer Module (SUB)
- Signal specification Signal Description, Subwoofer Module (SUB)
- See the relevant wiring diagram for information about circuit and ground terminals in the bodywork
- Checking wiring and terminals Checking Wiring and Terminals






Continue - DONE

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