BoostMaster

Car: 2000 A4 1.8tqm ATW engine

I got a CEL the other day and ran an OBDII scan. Got p1128 (lean code).

I replaced the front O2 and erased the CEL. The CEL came back in 1.5 days.

Ran a VAG scan. Got the following codes:
17521 (internal resistance too high)
17536 (system too lean)

I replaced two lengths of vacuum line that had not yet been replaced and that were frayed.

Disconnected the battery to clear the CEL and it stayed on.

I pulled the MAF and it looks fine. It's clean. I even blew it out with some air.

Still don't have a fix.

Can anyone advise as to what my next step is?

Ertman

run a log on block 003 at idle, then to WOT in third gear. A properly operating MAF will read between 2-4 g/s. If you are higher that, time for new MAF.

Then check block 032 - long term fuel trims

In general, an out-of-spec value in the first field (Additive) indicates a vacuum leak since it is mostly present at idle, when vacuum is highest. An out-of-spec value in the second field (Multiplicative) indicates a fault at higher RPM, and may point to a faulty MAF.<ul><li><a href="http://www.ross-tech.com/vag-com/cars/fuel-trim.html">fuel trim info</a></li></ul>

BoostMaster

I was scanned by a local who gave me the codes I posted.

I erased the CEL and it came back after a 1 hour drive on the highway.

I don't know anything about codes or how to locate them on Audi's. I just don't want to have to pay the stealership a bunch of dough for something I can fix myself. I guess I need to swap the MAF...

Is there a better MAF than the stock unit that I should look into?

BTW, thanks for the response. I need all the help I can get.

Scenic Driver

then a vag-com is essential. If you don't wish to buy one then you'll just be guessing and throwing parts at the car when something goes wrong.

And you can't tell if a maf is bad by looking at it (and cleaning them rarely works). The only way is by logging the blocks that Ertman mentioned above with a vag-com.

BoostMaster

however, this is my daily driver. I only have an MTM chip mod. There is no intake or exhaust- nothing. I need this car to simply be reliable and efficient.

Thus, I perform any and all maintenance necessary on my own. I have not invested in a VAG tool because I would never use it. This is literally the first time that the CEL has ever come on. (The car has 97k)

I modify and work on other turbo cars and have the proper diagnostic tools for them as they are toys that I can fiddle around with.

I did not think that cleaning the MAF would do anything (and mine wasn't really dirty).

The Vag run I had done was apparently done on a demo program and not the full blown edition. Is there anyone local that can scan my car with the full version? (San Diego) I just don't have the $200+ to spend on a tool I'll only use once. (besides, if I do need a MAF that $$ will cover the cost.)

Once again, thanks for the responses. I know newbie questions are annoying but I don't know where else to turn and the stealership is out of the question.

Scenic Driver

<a href="http://www.steve-hall.com/cgi-bin/VAG-Locator.pl">Vag-Com Locator</a>

Ertman

I have probably saved at least $2000 in parts and labor with it. Or, you can just go to the dealer and get *** raped by Conrad for $85 for a diagnostic that takes less than 5 minutes. Ore keep swapping out parts until you find the right combination.

BoostMaster

Don't get me wrong... I know that the diagnostic tools are real life savers. Stealerships for every brand of car I own are all the same. All they want is your money. However, the cars that I mod extensively are more prone to breaking and thus need constant monitoring.

My Audi is a DD and has only the chip mod. It has never needed anything that 1) wasn't covered under warranty 2) or wasn't regular maintenance (ie: timing belt which I did myself for $300 as opposed to the stealer's quote of $1200+)

That said, my current situation doesn't allow for additional expenditures that aren't 100% necessary and since I've owned the car for 5-6 years w/o issue, I can't justify the expense at this time.

I'm sure I'll break down eventually- The Audi is the slowest car in my "fleet"

BoostMaster

VAG-COM Version: Release 504.1-UD

Control Module Part Number: 4B0 906 018 P
Component and/or Version: 1.8L R4/5VT G 0006
Software Coding: 07201
Work Shop Code: WSC 06335
1 Fault Found:
17536 - Fuel Trim; Bank 1 (Mult): System too Lean
P1128 - 35-00 - -


I was told it's most likely the MAF. What do you guys think???