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Dave Roe
Dave Roe, Technician
Category: Audi
Satisfied Customers: 5
Experience:  Associate Degrees, Chassis, Engine Repair, and Powertrain
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AUDI A4 QUATTRO SEDAN: I have an 2003 Audi A4 3.0 Quattro Sedan.

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I have an 2003 Audi A4 3.0 Quattro Sedan. The "Check Engine" light showed on the dash. I had it scanned RESULTING IN A PO421 CODE INDICATING "WARM UP CATALYST BELOW THRESHOLD (BANK 1)". WHAT DOES THIS MEAN ?

Dave Roe :

What this code means is that your car's on-board diagnostic system has run a test on your catalytic converter and the result indicated that it is no longer effectively reducing your car's emissions. The manufacturer's recommendation is to replace the catalytic converter. i persoanally reccomend that a complete diagnosis be performed on the fuel and emissions systems be performed prior to replacing the unit.

Dave Roe :

To answer your other question about driving the vehicle, it shouldn't cause any immediate mechanical problems, however I don't recommend driving for any extended periods because since the check engine light is currently on, you won't be aware of additional codes that may occur.

Dave Roe :

I am switching this to Q and A mode since you have exited this chat. Please let me know if you need more information.

Customer:

THANK YOU FOR THE ADVICE ! I HAVE MADE AN APPOINTMENT ON THIS MONDAY TO HAVE A "COMPLETE DIAGNOSIS PERFORMED ON THE FUEL AND EMISSIONS SYSTEMS PRIOR TO REPLACING THE CATALYTIC CONVERTER. WOULD YOU LIKE A FLLOW UP REPORT ? IF SO, LET ME KNOW HOW TO CONTACT YOU WITH A RETURN MESSAGE. Kathleen Doetzer

Our chat has ended, but you can still continue to ask me questions here until you are satisfied with your answer. Come back to this page to view our conversation and any other new information. I just noticed a typographical error in my response from our live chat. I meant a complete diagnosis of your fuel and IGNITION system, not emission system. Sorry for the confusion!

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--Dave
Customer: replied 3 years ago.

Just wanted to let you know the resolution of the "check engine" dash warning sign on my 03 Audi A4 Quattro Sedan. A complete diagnosis of the fuel and ignition showed a insufficient level of emissions cleaning by the 2 Banks on either side of the Catalytic Converter. The mechanic showed me the very gummed up Banks and explained the problem. They were replaced and my Audi is back to normal now. The high performance engine is running like new and I'm a very happy Lady : ) !!!! Thanks again for your help. I'm so happy to have found the Just Answer Online Service and Dave Roe. Kam


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