P0139

2C7B - P0139

Information saved in
DME

Fault code
2C7B - P0139

Fault text
Oxygen sensor behind catalytic converter, signal

Fault description
O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)

Condition for fault identification
Test condition:
O2 sensor behind catalytic converter voltage too high with
overrun injection deactivation active; signal sticks at rich
Terminal condition: Terminal 15, engine on
Voltage condition:
none

Condition for fault memory entry
Voltage > 0.2 V

Action in service
1. Check wiring
2. Check plugs
3. Measure wire resistance against positive and ground
4. Replace Bank 1 downstream (post-cat) O2 sensor

Fault effect and breakdown warning


Driver information
Warning light:
none

Service instruction
none