Electrical - MMI/Audio and Battery Concerns

Group: 91

Number: 05-03

Date: Mar. 24 2005

Subject:
Multi Media Interface (MMI), Audio, and Battery Concerns

Model(s):
A8, ABL, A6 See Table

Condition





At ambient temperatures below 40° F, processor failure in the radio can cause any one of the conditions listed below. Another symptom of radio processor failure is waking up of the Media Orientated Systems Transport (MOST) / Can Bus system. This symptom will eventually deplete main battery voltage.

1 - MMI is slow to respond.

2 - "Radio Not Installed" is displayed in the MM screen.

3 - Poor radio reception.

4 - Engine will not start.

Service

- For condition 1, perform steps A and B. If OK, replace radio.

- For condition 2, replace radio.

- For condition 3, perform steps A, B & C. If OK, replace radio.

- For condition 4, perform steps A, B & D. If OK, replace radio.

Tip:

Step C applies only to the A8 and A8L.

Step A:

- Check the MMI, Radio and Battery Manager for DTC's.

- Repair or replace components as necessary.

Step B:

- Perform a ring break diagnosis using VAS 6186 MOST repeater (see Tip below).

Tip:

When performing the ring break diagnosis, follow the literature that is provided with special tool VAS 6186. For additional information on fiber optics, refer to Audi Self Study Program (SSP) 971303: New Data Bus Systems, Fiber-Optic Data Bus.

- Repair or replace components as necessary.

Step C (only applies to A8 & A8L):

A defective Antenna Selection control module -J515- can cause poor radio reception. This can be checked as follows:

- Remove rear headliner / roof frame trim.

- Select AM/FM station where customer has the reception issue.





- Gently push Antenna Selection control module -J515- (black arrow) in the center against the glass using a non-metallic object (e.g. wooden dowel or pen).

^ if Antenna selection control module is faulty, an improvement of the reception quality can be heard.

- Repair or replace component as necessary.

Step D:

- Check charging system and battery condition.

- Repair or replace components as necessary.