Skip the auto shop - Our mechanics make house calls

Q: Alternator Fault

asked by on

I have a late model 2008 Audi A4 (euro). For the last few months I've been having constant trouble with a fault in the car. For no reason the car started with a message on the dash "Alternator Fault. Battery not charging". Sometimes the fault will go away from a few minutes to even a day after turning off and restarting the car. I've had the regulator and brushes in the original unit replaced, I had another alternator fitted, a new regulator fitted in that unit and a brand new battery fitted. None of these attempts have stopped the fault from returning. The latest fix, fitting a new regulator in a used alternator has worked fine for the last two weeks but today the warning light has returned and left me having to jump start the car to get going again. The light is now appears immediately after starting. I find it hard to believe that it could really be an alternator problem given that I had refurbished the original unit, and refurbished and fitted another one with the same results.

My car has 190000 miles.
My car has a manual transmission.

You will need to check the one way clutch pulley on the alternator to see if it operates as it should.

First remove the belt. Then using a plastic or non conductive blade and put it in the alternator rotor to hold the alternator from turning. Now turn the one way clutch pulley. It should turn easy in one direction and not turn at all in the other. If the pulley turns in both directions or binds at all, then it is defective and should be replaced.

If the pulley works as it should then you will need to inspect the wire harness to the alternator and the fuse box for any loose or damaged connectors/wires and repair them as needed.

If you need help with these checks, get some help from a professional mechanic who can diagnose this warning light firsthand and make the necessary repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Alternator Fault

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Possible blown head gasket issue - 2008 Ford F-150

Hello. If it has a blown head gasket it can be quite the undertaking to fix this. You would need to remove the cylinder heads and have them fully rebuilt prior to reinstalling them. If you have a lot of...

Q: P2196 OBD-II Trouble Code. came and went in 24 hours. 4 starts.

If the mechanic tested the output (functioning) of the oxygen sensor, especially according to the protocol at this link and found that the sensor was non functioning at that time, what you might be experiencing is a "failing" oxygen sensor...

Q: Temperature Gauge

With most any other vehicle, your diagnosis would be dead on, congratulations! In your case, the problem is most likely the thermostat. With this Audi engine, the Audi engineers were more clever, there is only a single coolant temperature sensor,...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.