Failed Emissions
 

Recently went for a routine NY State inspection and was told the car failed the emission. Specifically the on-board diagnostic system of the vehicle indicated that there was a failure in the Malfunction Indicator Lamp. In a nutshell the "Check Engine" indicator would not come on.

After $600 of diagnostic and vacuum line replacement, the local shop guys still couldn't get the system to turn the Check Engine indicator on. They suggested another day of diagnostics to check the ECM and OBD units, the wires from the units to the dash indicator, and the dash indicator lights.

I called Audi, who informed me that the ECM and OBD are covered under a federal required warranty (8yr/80k) and suggest that I take to the dealer for ECM and OBD diagnostic and potential replacement. Dealer stated that they will happily diagnose yet there is no guarantee that its the ECM or OBD. They also told me to be prepared that if its the dash indicator, this would require a dash replacement at $1,500. I feel like I'm getting set-up for a $2,500 stealer bill.

Any words of wisdom on this? If it is the ECM or OBD, only the dealer can perform the "warranty" replacement. Thanks.

What ever happened to sticking the prod in the muffler and testing for actual output?

Re: What ever happened to sticking the prod in the muffler and testing for actual output?
 

The irony here is that my car failed NY emission because the light won't come on, not that it won't turn off. Also, the actual emissions from the car is not a problem!

NY is generous. Because I spent over $450 trying to address the problem they give me a 1 year waiver so I have time to properly address the problem.

Got any trouble codes in the instrument cluster?
 

$600 and vacuum line replacement in order to turn on a light? Does not inspire confidence.

Does the warranty cover on board diagnostic (OBD) failures that don't affect emissions performance? If so, this should qualify, since a trouble code was stored and having no check engine light impairs OBD.

If not under warranty:

Can you find out by which code "the on-board diagnostic system of the vehicle indicated that there was a failure in the Malfunction Indicator Lamp"? The only such generic OBD II code I see is P0650, which doesn't appear in the A8 service manual for the 2000 model year.

Were there any trouble codes in the instrument cluster? Does the instrument cluster's output diagnostic test turn on the check engine light (expected if this lamp doesn't have its own wire from the ECM)? Are your ECM and instrument cluster coded correctly? These are easy tests for a shop or person with the necessary tools, e.g. VAG-COM and a service manual. If the local shop doesn't have such, they shouldn't be doing this work.

The wiring diagram shows no dedicated wire between the ECM and instrument cluster for the check engine light or the EPC light. But there's a CAN-Bus link between the ECM and instrument cluster, which the manual says carries the consumption signal for the mpg display and the antitheft immobilizer. It may also be how the ECM turns on the check engine light. You haven't had any problems with the immobilizer or mpg readout, have you?

Tom

So, the check engine light does not come on with the
 

engine unstarted and the key in the on position?

If so this is probably a simple fix in the cluster.

If the light is good and it recently turned off after a fix, it takes something like 40 key starts to clear the OBDII menory, even if the ECM is not throwing any codes (or a CEL).

You're getting a hard lesson in why it's difficult to own these cars without owning a VAG-COM and a
 

Bentley CD.

If the CEL comes on prior to start, just drive the car for another week to clear the
 

OBDII memory and try the test again.

If the CEL light is off (and functioning)it is impossible to fail a scanned OBDII emission test.

Not true, on that second.
 

It is indeed possible to fail a scanned OBDII emission test, with the CEL off. BTDT.

You can have a stored code that doesn't allow the "Emissions readiness" flag to be set positive in the ECU.

I check said flag with the BAG-COM before going to the emissions hut every year, now.

I doubt it, I studied this extensively when getting my car
 

certified for us emissions in Illinois. I don't think this is true.

The OBDII system is designed to show a CEL when there is an emissions related event.

What is BTDT

Been There, Done That.
 

All I know, is that I did NOT have emissions readiness, and did NOT have a CEL.

Ever touched a VAG-COM? Or is your extensive study all theoretical?