I just bought a 01 a4 1.8t and it has several dash lights on. ABS, Check engine, EPC, Airbag, and the light with the exclamation point with the circle around it are all on. If I unhook the battery for a hour and then reconnect and start the car the airbag light stays on all the time and never will go off so I figure the airbag sensor is bad. CEL comes back on after a while for a maf code. And the EPC, ABS, and exclamation point lights all slowly come back on within 10 mins of driving after reconnecting the battery. I don't know why these 3 lights would be on. If it was a bad ABS module wouldn't the brake light be flashing also?? And i have no idea about the other 2 lights. The only problem I know is wrong with the car is it needs a new coolant temp sensor. Any ideas??? Thanks

 

first thing that comes to mind is that your alternator is not working properly. if you are getting a voltage drop the car starts "turning off" its electronic features to keep the engine running as long as possible. first the battery light should come on, followed by exclamation point, EPC, and ABS lights.

airbag light is probably a loose connector. do a search and you should find a fix. it is pretty common and an easy fix.

good luck

 

My guess is you have all of those problems. If you dont have a flashing brake light, you probably have a bad wheel speed sensor. The airbag light must be reset, disconnecting the battery doesnt do anything. And you should scan the for engine codes. Pretty much first step, get a VAG COM.

 

I found out the EPC light is on because of code P0322. Car died then wouldn't start back up. I looked at the connections under the coolant resevior and I found a few exposed wires. One on the white speed sensor connector another on the blue connector and another on the green connector. Not sure what the green and blue connectors are to but I'm going to fix all exposed wires and hopefully this will fix the no start/hard start issue.

 

i hope u got a good deal and its in good cosmetic condition at least.

 

I got it for a complete steal actually.. Exterior and interior are near perfect.. And I found out why all of the lights are on. EPC=crankshaft sensor, CEL=MAF, Airbag=Probably just needs to be reset with vag but at the worst its the bad airbag sensor under the seat, ABS= Probably wheel speed sensor, the only one I didn't really figure out is the traction control light which is weird since the car is quattro so shouldn't even have any kind of traction control, but it does have the ESP button??? Weird..

 

Later models have ESP (on a side note, ESP works by steering the car by braking the rear wheels, it needs to know a number of things, one of them being the speed of the wheels) even with quattro, and ESP cant function without ABS, hence the light.

 

Does the ABS light come on as soon as you turn the key ON? In my experience if this is the case the module will need to be rebuilt. Otherwise if the ABS light comes on after driving for a bit then there is an issue at one of the wheels.

 

Great info Dallas... I never would have thought of that that the ESP would not work if the ABS is not working correctly. Nice call... As to Metalman, I thought if the module was bad the ABS and the brake light would both be on? Correct me if I'm wrong and the brake light does work with the ebrake engaged but never comes on with the ABS light. Either way even if its a bad module its still very simple to fix just a bit more expensive than a wheel speed sensor..

 

Ah for some reason I thought the BRAKE light also came on with the ABS light. So it's not the module.

My guess now is yours: damaged ABS sensor. But it would have to be quite damaged or have cut wiring for the ABS light to come on when the key is turned ON. A proper diagnostic tool such as Ross-Tech VAG-COM will allow you to find out which sensor is causing the issue without taking off each wheel and checking each sensor.