Symptom Related Diagnostic Procedures

Checking complaints about car radio system

Malfunctions in radio system
1. Check error and customer complaint.
2. Switch ignition off and remove ignition key.
3. Remove radio fuses (ignition and memory).
4. Wait approx. 3 minutes until all components are free of tension.
5. Insert fuses again.
6. Check error and customer complaint again.

Work Instruction 1 - 4:

Work Instruction 5 - 6:

Reduced sound quality in one or more loudspeakers

NOTE: Reduced sound quality may be accompanied by a humming nose

1. Switch on the system and change the fader and balance setting on the radio.
2. Check the fault status.
3. Find out on which channels the problem occurs.

Work Instruction 1 - 2:

Work Instruction 3 - 4:

Remedying problems with the amplifier

Work Instruction 1 - 3:

Work Instruction 4 - 5:

Interference noises

NOTE:
- This procedure is designed to help you find out how the interference noise has entered the system.
- In the following information, the various interference noises are differentiated.

- The battery must be fully charged.
- No charging unit may be connected.

Work Instruction 1 - 4:

Interference noises, checking cable connections

NOTE: Procedure for interference noises which enter the system via the audio connections.

Work Instruction 1 - 4:

Interference noises due to alternator

Work Instruction 1:

Interference noises due to engine
The following points should be checked first:

NOTE:
- Make sure that the battery connections are seated properly and that the ground connection is guaranteed.
- Check whether the ignition coils are loose or defective.
- Check the plug connections and supply lines for the ignition coils for damage.
- Check the ground connections on the engine.
- Check whether the correct spark plugs have been installed and that the electrode gap is OK.

Work Instruction 1 - 3:

Interference noise due to antenna

NOTE:
- Follow this test routine if the interference noises come from the antenna.
- As an experiment, it is worth making a comparison by inserting 3 rod antenna.

Work Instruction 1 - 2:

Interference noises due to power supply

NOTE: Use this test routine for interference noises which originate from the vehicle electrics.

Work Instruction 1 - 5:

Work Instruction 6 - 8:

Interference noises due to all loudspeaker

NOTE: The loudspeaker leads are twisted together as standard.

Work Instruction 1 - 5:

Electromagnetic compatibility (EMC) - Troubleshooting

NOTE: Check the complaint to make sure that the symptoms really exist.