MNaudiguy

Hi All,
New member and could use your help. I have a 2001 Allroad 2.7T auto. It's in the shop at an Audi Dealership (yes, shocking I know). I did some various work to the car: T-Belt and Water Pump, CV Boots, O2 sensor. After the mechanic was done he took the vehicle for a test drive and saw the battery voltage meter registering around 12V. He tested the battery....battery was bad. He replaced the battery with a new one. Battery tested fine, but alternator was still only charging at 12.5-12.65 volts. We replaced the alternator with a brand new alternator and received the same readings (12.5-12.65V). We assumed that alternator could have been bad fresh out of the box and replaced it with another alternator....yep, same measurements. So, the mechanic has traced all the grounds, wires, checked fuses, etc... No answers. He checked the battery cables on both sides and has done Voltage Drops. Still 100% dead end.

Please for the love of god help me get this beast back on the road..

IDEAS???

awdjunkies

Okay so does that mean that the needle indicates 12.5 or so, when the key is inserted? or when the car is running?
I know weird/dumb question. I don't like to redirect people to another forum, but in case you don't get what you seek within a couple of days? You may also want to try checking/posting at the other Audi site, audizine.com which has a lot of Traffic as well.


PS: Welcome to audiworld by the way.

MNaudiguy

Thanks for the reply. When the car is running 12.5. Under load it drops to about 12. There is a VERY SMALL voltage drop of .3 volts from the positive battery terminal to the alternator, but I'm looking to find 13.5-14 volts, so it seems as if the battery cable may not be the real issue. Replacing it means ordering a part from Germany and $200 PLUS labor---and that doesn't guarantee it getting fixed. 12.5 plus .3 is only 12.8....

The tech also hooked up a different instrument cluster thinking that could be it....nothing. Basically running out of options. I read somewhere there is a 140A alternator, but according to Audi's system this VIN Allroad gets a 120A alternator, which is in it now.

Feel like I'm just throwing things at it and hoping something sticks.

mad8max

From my understanding (recently replaced battery), whenever you replace the battery, the cars computer must be formatted to managed the new battery. I noticed after installing the battery, the voltage was around 12.2Volts, as to it WAS around 13 - 13.2. The tech hooked up his OBD, cleared out the code, resetting the cars computer, allowing it to manage the batteries voltage. Since clearing out, the voltage averages around 13 at idle and a little over 13 volts when driving.

So, just simply clear any code out, that will reformat computer to manage the new battery. Hope that helps.

knightowl71

Did clearing the codes fix your problem?

I ask because I have a similar problem. I replaced my battery back in November. I did not have any problems until April of this year. At start-up, the battery light came on in the dash. The meter was showing close to 14 volts. I stopped by Advance where I bought the battery thinking if it was bad, they could just replace it on the spot. They tested the battery and it showed that is was good. I had them test the alternator just in case, it showed good also. At this time, the light was out.

The light did not come on again until about a week later. Again, it was on for awhile then mysteriously went out. During the times that the light was on, I did not experience any symptoms of anything being wrong.

Unrelated, the allroad failed emissions due to the air pump system. It sounds like a jet engine at start-up. Because it did not pass, it is not legal to drive so it has been sitting for 3-4 weeks. I have started it a couple of times to make sure it would start and to charge the battery a little.

Over the past 2 weeks, the air suspension has dropped to where you can see a significant change in stance. Although it looks cool, it is not at an acceptable ride height. I went out to start it up the other day to let the air system pump the suspension back up while charging the battery. I planned on taking it to the dealer for an estimate to get it fixed and through inspection. This time, the battery light lit up as well as the suspension light. I figured this was because it was so low and that as the system stabilized, the light would go out. The system did not stabilize. The lowest light on the suspension control is flashing like it does as the system works to reach the desired level. However, it does not reach the level. I dont even hear the compressor running.

As I was sitting in the car waiting for the suspension to raise, the radio turned off. Then the dash dimmed and the batter meter started dropping. The needle dropped all the way down to the left and the car seemed like it would stall. I gave it some gas and it seemed to regain some power but still not much and faded as I took my foot off of the accelerator.

My battery charger shows a voltage of 11.6 at the battery and the car starts fine. My concern is what else could be wrong that I did not test? Also could the lack of sufficient electrical power be the cause of the suspension not raising or is this a separate problem?

I know this is not the best way to diagnose but with me losing my job recently, I dont have the money to be supporting my local dealership right now. I mainly want to figure out if this seems like a larger problem and have to seriously consider selling due to my financial situation. I want to be able to speak to the issues it has with a potential buyer if it comes to that.

Thank you for any insight and help with this situation.

Chris

mad8max

If you're able to get the car started and drivable, take it to any local shop and ask if they can use their OBD computer to clear the codes. clearing the codes should allow the cars computer to now manage the new battery's voltage and amperage. It worked on mine. If that doesn't work, then you may need a shop with a VAG COM to clear it out and reset. Some shops may charge you, some may not. Mine did not.

knightowl71

Thanks. No one around here will do it for free. I have been out of work so $100 is painful right now just to see if it works. Just wondering though, if I installed the battery in November, would it work fine until now then suddenly need to reset the codes? Does this seem reasonable?

Thanks again.

awdjunkies

At this point anything is possible.

allroaddave

I changed the battery in my 2004 Allroad, I didn't have to reset any computers or codes, and it works fine.

Did you have the alternator itself checked out - is it putting out the right voltage? If it's putting the right voltage and it's not getting to the battery, you have a relay or cable problem.

Knightowl, you can fix that air pump issue if you're handy with tools and such, I did a write up on fixing mine, search for Secondary Air Pump. I think I spent less than $20 for new bearings.

For your other problems, try charging the battery up fully first, then see what it does.

Anytime you leave one of these modern cars sit for more than a couple of weeks, you need a battery minder to keep the charge up to snuff.

Ride2Live

A couple of things but maybe you have already did this. 1 measure the battery voltage with a good hand held meter (Fluke if possible) it should read 12ish with the car off and 13.5ish while running. 2 its possible that when you did the timing belt that you were given the wrong size serpentine belt which drive the alternator. 3 check the serpentine belt tension. you could have a problem with the belt tensioner.