gabe1017

For the past week my 2005 audi A8 has been having various issues that my mechanic says are related. First it started with my interior door lights pulsing/intermittent, usually on cold days. Next the parking brake light came on my dash a few times. My sunroof and dome lights in the car were not working as well. Then my alarm would go off non stop when the car is locked until the battery dies. So at first I started disconnecting the battery when not driving but now i am just leaving my car unlocked. A day later all the issues stopped and everything worked fine. Then start happening again and then stops hours later. The last problem that happened a few times was while driving, all interior lights and dash would completely shutdown, including the heat and my speedometer. The driver screen read out would turn completely RED. Two times I think i even lost power steering momentarily. Today everything on the car is working fine....


After bringing it to a mechanic and testing fuses, some wires and clearing the codes. He said it is my comfort control module. Checked the comfort control module in the trunk by the battery, and everything was intact, no corrosion or damage.Could that be the cause for all of these problems? What else could I look for?

Codes pulled:

01308 - Control Module for Roof Electronics (J528)
01336 - Data Bus for Comfort System: Faulty

01330 - Central Control Module for Central Convenience (J393): Faulty

(P1570) Engine Start Blocked by Immobilizer"
01299 - Diagnostic Interface for Data Bus (J533): No Communications

JohnnyJ A6Q

How old is your battery ?

gabe1017

Over 5 years. Never had any battery issues until the alarm problem. Should i start with changing the battery or as long as it puts out the proper voltage, leave it?

JohnnyJ A6Q

Remove it and have it condition and load tested.
Mine was original (9+years) and even though it would start fine for daily driving, things started acting a little wacky if I did not drive her every day, if it sat for two or three days, the MMI battery meter would show anywhere from 5-20 % life, but she would still start, but only one start, if I shut it down within 10 minutes of drive, then no start, but also my keyless entry would not work, nor the convenience windows or certain lighting, and I did get the red screen once, after new battery install all is good.

Mister Bally

For starters, disconnect the alarm module (under hood, below windshiled on "right" side which is determined by sitting in the driver's seat). We don't know where you are located.

See the sticky at the top of the thread for all of your answers.

MP4.2+6.0

+1 on this angle. Battery old enough and electrical flakiness in D3 has been correlated to failing batteries in a variety of cases. I would run that down thoroughly--or just change out given its age--before spending money and labor $ on other ideas.