How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask eauto Your Own Question
eauto, The Car Guy
Category: Audi
Satisfied Customers: 16286
Experience:  ase mechanic
Type Your Audi Question Here...
eauto is online now
A new question is answered every 9 seconds

Audi a4: my 2005 3.2 audi a4 has a check engine light on it

This answer was rated:

my 2005 3.2 audi a4 has a check engine light on it that is on constantly and won't pass inspection....this is my 2nd audi with this problem and it always happens after warranty has expired....what can I do to get this fixed? Also, my oil is running low now every 1,000 miles (for last 2,000 miles) and is not leaking...

I wasn't planning to get a new car so need your help...thanks.
Hi . Thank you for asking your question on JustAnswer. have you had it scanned for diagnostic codes?

Thank you again for trusting us with your problem. John aka eauto
Customer: replied 3 years ago.

yes, I believe my mechanic scanned it...but I need to check with him re the check engine has been constant for the last 40,000 miles....he resets it and then it comes back....

can you get me the code?
Customer: replied 3 years ago.

I can try tomorrow...will this be part of the original question? thanks.


The check engine light comes on when the on-board computer detects a fault in engine driveability or performance, transmission control system or transmission, or the emissions system, and a fault code is set and stored in the computer. Faults that can set the check engine light can range from a vaccuum leak, engine mis-fire, low engine compression, faulty sensor such as O2 sensor or other engine sensor, hydraulic pressure loss in transmission, transmission shift solenoid, open/short in wiring harness, emission evaporative system leak, or one of over a hundred different reasons.
The only way to know what set a fault code and turned the check engine light on is to have a diagnostic scanner hooked up to the on-board computer and read it for stored diagnostic fault codes. Many auto parts stores will do this service for free- (like auto zone)check with you local parts stores. If none in your area do, then you will have to take it to a shop and pay to have the computer read for stored fault codes.

Without knowing the fault codes numbers, it would be irresponsible to guess as to the cause as there are hundreds of possible causes

if you provide me a diagnostic code we can narrow down the cause of failure

Customer: replied 3 years ago.

the answer to oil low was not answered....

low oil can be caused by leakage or burning, a oil consumption test can be performed by the dealership, It may be a internal issue a leak down and compression test is the next step
eauto and other Audi Specialists are ready to help you