12A101

12A101 - P2271

Information saved in
DME

Fault code
12A101 - P2271

Fault text
Oxygen sensor after catalytic converter, system check:
signal fixed at rich

Fault description
The diagnostic function monitors whether the voltage of the
oxygen sensor behind catalytic converter remains stuck at a
high value.

Condition for fault identification
Test condition:
The fault is recognized when the voltage of the oxygen
sensor behind the catalytic converter remains consistently
too high.
Potential problem source(s):
- Mixture too rich
- Defective wiring harness
- Oxygen sensor behind catalytic converter defective
- Defective DME
Terminal condition: none
Voltage condition:
- Onboard electrical system voltage between 9 V and 16 V
Temperature condition:
- Engine warmed to normal temp, above 80 °C
Time condition:
- None
Other conditions:
- Engine on
- Steady-state at low to medium partial load

Condition for fault memory entry
The diagnostic fault code is logged when the fault remains
present for longer than 10 min.

Action in service
- Inspect wiring harness between oxygen sensor behind
catalytic converter and DME
- Replace oxygen sensor behind catalytic converter
- Replace DME

Fault effect and breakdown warning
Breakdown notice:
Continued driving is possible, but because the oxygen
sensor is not ready for closed-loop control, conversion of
exhaust gases in the catalytic converter will be seriously
impaired.
Possible apparent symptoms:
MIL lights up when fault is detected in two consecutive
driving cycles

Driver information
Warning light:
- ECE emissions warning lamp: on
- ECE electronic engine power reduction: on
- CC message: on
- US emissions warning lamp: off
- US electronic engine power reduction: off
- CC message: none

Service instruction
None