Car Problem Reports

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

Audi TT Quattro Problem
21 Reports
Me Too

Model Years Affected: 2000, 2001, 2002, 2003, 2004, 2005, 2006

Exhaust & Emissions Affected: 1.8L 4 Cylinder Turbo

Average Mileage: 90,331 mi (55,333 mi - 115,650 mi)


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

  • Visitor, , 100,000 mi

    Check engine light will not stay off, says it is the O2 Swnsor. Replaced it and now its back on..Frustrated.

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  • Appears to be the caused by the failure of the air pump and air valve. Apparently a common problem as I have a friend with a simliar age TT that has the same issue. The pump keeps the fuel tank pressurized so if it fails the diagnostic system thinks there is a vacuum leak.The car will fail an emisions test, but the car is still usable until you can get it fixed. Cost is around $800.

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  • Visitor, , 107,000 mi

    same problem replaced one cat. converter twice 1st one failed. still coulden't get pass from DEQ, changed out oxygen sensor and made it through. but have still hava problems with engine light.

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  • I have had my car in the shop several times due to Vacuum leaks, oxygen sensor failure, and catalytic converter efficiency faults that cause the Check Engine Light to illuminate, to the tune of approximately $1500 over the past year. Both repairs were made between 90-95K miles(currently has 96K miles). Now I'm looking at possible modulator failure. Doors won't lock, inside lights don't work, convertible top doesn't work, and car doesn't recognize key remote! Air bag light is on also???

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  • Visitor, , 67,000 mi

    engine light on. shop says maf sensor problem

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  • Visitor, , 85,000 mi

    replace o2 sensor

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