Check Engine Light Due to Vacuum Leaks, Oxygen Sensor, or Catalytic Converter Fault on Audi S4

Problem Description and Possible Solution

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

Problem Data
RepairPal Verified
Average mileage: 149,000 (149,000–149,000)
3 model years affected: 2000, 2001, 2002
5 people reported this problem
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Viewing 1 - 1 of 1 comments
My check engine light hardly ever goes off. The problem from day one has been the oxygen sensors. I have had them replaced twice within the last three years and the problem has not gone away.