Check Engine Light Due to Vacuum Leaks, Oxygen Sensor, or Catalytic Converter Fault on Audi A6 Quattro

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

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Average mileage: 117,368 (10,900–200,000)
Exhaust & Emissions affected: 2.7L V6 Turbo
5 model years affected: 2000, 2001, 2002, 2003, more2004
30 people reported this problem
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Viewing 1 - 11 of 11 problem details
2001 Audi A6 Quattro 100,000 mi,
Check engine light is on, code is reading O2 sensor
My check egine light is back on only two days after a tune up correcting missfire i dont have the funds to replace either catalytic converter or O2 sensor at this time but this is what the code is fuel too rich watever that means.
2002 Audi A6 Quattro 120,000 mi,
catalytic converter insufficient flow cause CEL on
the engine light is on and i cant drive the car cause it will cut off and oil is leaking
2001 Audi A6 Quattro 80,000 mi,
Have been told that it is the O2 sensor. I have had them replaced and the CEL is back after 10k miles.
vacuum leak code (p4117)
check ingine light car seems to slow down and pick up at times
2002 Audi A6 Quattro 128,000 mi,
CEL on. Checked OBDCOM--diagnoses was improper Catalytic converter air mixture coming from back O2 Sensors. Will replace catalytic converters and O2 sensors.
Car looses power, then surges all of a sudden, then act like it wants to shut off. Fumes coming into drivers area bad enough to burn mu eyes.
po172 and po175 what is this code
Have this problem as well, need to assemble funds to fix it.