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Hey Guys,


Help needed please.

Have a temperamental Audi a7 that starts fine "sometimes" then other times 

kicks up a ESP fault alarm and wont start.

once this alarm shows i get a host of other random alarms also

TPMS fault

Gearbox Malfunction 

Parking Brake

Headlight range control


then when i switch off the car, lock it and reopen and switch on it will start most

times and the alarms are no longer showing.


when the car is running it runs fine.


I have replaced the battery and cleared the alarms in the car but the same problems persist. 


This car had a new gearbox and engine seals also done by audi over the last 2 years.

other parts replaced where the brake disks, pads, wishbones, track arms, grease boots.

general service wear and tear stuff.




Cheers Guys 

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As you've changed the battery, have you checked it's holding charge or that's no battery drain on the car. 

Also is it worth having an auto electrician check the wiring loom for any loose connections or frade wires etc. 

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Hi Steve

I have had the car to a guy who said it could be one of 3 things... the start button, the brake light switch or the



i did have other guys who said, wheel speed sensor and gear box sensor but this guys said no as they 

are only activated when the car is in motion...


The problem is very strange in that it only comes on when you go to start the car. sometimes good, and no 

alarms, drives like a dream. then others stuburn as a mule.


we are going at the brake light sensor and start stop switch first.. keep you informed...


Ah Audi! 😄


oh thanks for the reply... i'll have them look over the looms etc while its up in the air. 

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get all codes read and look for common denominator between the modules like an earth fault or similar, im guessing its a canbus fault ( communication error similar in each module thats throwing a code) thats intefering with the bus line and intermittent when asking for a cold crank/ high current.

id be looking at gbox/engine/chassis earthing as audi have been in and about that area then looking at gbox plug for the engine egr cooler leak down loom into the plug at gbox.

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Hi Robster

thanks for your reply, after a couple of changes with no success, start stop switch, brake light switch, checking all the wiring 

and fuse boxes, cad the ecu checked also etc, Audi found it to be the brake pedal switch. (Thank god) €27 (phew)

Attached is a video of the problem...

first is the esp fault.. let the car settle and it started with no issues.

Thanks again for your reply on this.

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When i went to collect the car they said the bug came back, they then changed the relay at

terminal 20, this seems to have corrected the issue.


Hope this helps 



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