P0139low severityPowertrain
O2 Sensor Circuit Slow Response Bank 1 Sensor 2
on 2021 Audi A6 2.0L Turbo I4 · AWD
What this code means
The downstream O2 sensor on Bank 1 is responding too slowly.
Symptoms
- Check Engine Light
- Failed emissions
Common causes
- Aging sensor
- Contaminated sensor
- Catalyst issue
Diagnostic steps
- Monitor sensor response
- Check catalyst efficiency
Repair notes
Replace downstream O2 sensor.
Other Powertrain codes on this vehicle
P0001
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P0002
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P0004
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P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
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P0012
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P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1