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

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

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Average mileage: 99,200 (54,000–155,000)
Exhaust & Emissions affected: 1.8L 4 Cylinder Turbo
12 model years affected: 1997, 1998, 1999, 2000, more2001, 2002, 2003, 2004, 2005, 2006, 2010, 2012
26 people reported this problem
5 people shared problem details
2002 Audi A4155,000
Catalytic converter is bad. :( must replace before next smog check.
check engine light on
2010 Audi A482,000
engine light came on, checked code and it read PO420 catalyctic converter maybe bad
Crankcase breaker system was replaced to correct check engine light fault. Symptoms were: check engine light and rough idle.
2004 Audi A498,000
Blinking engine light - diagnosis bad hoses, etc in need of immediate repair.
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