Car Problem Reports

Audi A4 Quattro Check Engine Light Due to Vacuum Leaks, Oxygen Sensor, or Catalytic Converter Fault

Audi A4 Quattro Problem
43 Reports
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Model Years Affected: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006

Exhaust & Emissions Affected: 1.8L 4 Cylinder Turbo

Average Mileage: 109,376 mi (56,000 mi - 153,000 mi)


Vacuum leaks, oxygen sensor failure, and catalytic converter efficiency faults can cause the Check Engine Light to illuminate.

  • Visitor, , 110,000 mi

    I have had my check engine light on for last month. The mechanic at the shop put the computer on it and it says bank 1 lean and mis fire on pistons or something like that? The car runs fine but ideals rough.

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  •  Rookie

    Replace vacuum hoses

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  • Visitor, , 151,000 mi

    Check engine light on. Went to Auto Zone to get a reading and the codes read that it can be a faulty turbo, catalytic converter or an air leak.

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  • Visitor, , 140,000 mi

    My Audi has all the same problems.

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  • Visitor, , 92,000 mi

    check engine light came on - catalytic converter insuffiency - replaced converter and check engine light has come on again after 1,300 miles with new converter. Obd has to be read again. Vehicle seems to be running okay.

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  •  Rookie

    The check engine light remains on. Replaced gas cap about 2 years ago. I have worn hose, that probably is leaking air. Not sure how to affect repair myself. The problem seems to be effecting my mileage performance now.

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  • Visitor, , 85,000 mi

    I bought the car used in 2007 and it's been on ever since. We changed the sensor and it's still on. the cluster also has a problem with displaying and we got a 'used' one and still have the same problem. The electrical system must be messed up as the car alarm would go off for no reason. It's ok now. The engine is terrific and handling is great, it loves the road even in 2014 with 144,000 mi on it.

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  • Visitor, , 122,000 mi

    Check engine light has come on. P0431 warm up

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  • Visitor, , 71,000 mi

    Check engine light came on, dealer says its the Catalytic Converter on the left side. Wants $2400 to fix. 2003 Audo Quattro 3.0

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  • Visitor, , 114,000 mi

    There's not too many details. We bought the car yesterday and last night the check engine light came on. Saturday night meant a quick detour to Auto Zone and the code read for the catalytic converter. We're concerned also that the 75000 mile timing belt was not changed (dealer said the service records were lost and there was now telling). Our efforts to find a solid, used and affordable car seem doomed; it's a pretty grim morning.

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