Condition For Fault Memory Entry - 1

2C6B - P2270

Information saved in
DME

Fault code
2C6B - P2270

Fault text
Oxygen sensor behind catalytic converter, system check

Fault description
O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 2)

Condition for fault identification
Test condition:
Oxygen sensor system check
Oxygen sensor voltage too low = Signal sticks in lean range
Trim controller diagnostic routine must be completed, see
Trim controller diagnosis. Detection of faults during the trim
control diagnosis triggers the active test. Engine running at
idle is adequate for the active test;
Terminal condition: Terminal 15, engine on

Condition for fault memory entry
O2 sensor behind catalytic converter voltage < 0.2 V with
rich data specification for active test

Action in service
This malfunction is detected during the active test. The
active test is triggered by the trim control diagnosis function
(trim controller fault code stored in the control module's
fault memory!)
1. Initiate system test for reversed O2 sensors. Follow
instructions for system test.
2. If the system test fails to produce a result then
3. Visual inspection of wiring and plugs
4. Electrical check of wiring
5. Replace wires or plugs as indicated
6. Check exhaust system upstream from downstream (post-
cat) O2 sensor for leaks
7. Replace downstream (post-cat) O2 sensor
8. Replace upstream (pre-cat) O2 sensor
9. Replace control module

Fault effect and breakdown warning


Driver information
Warning light:
MIL ON

Service instruction
none