Engine Controls System: 128901

128901 - P0133

Information saved in
DME

Fault code
128901 - P0133

Fault text
Oxygen sensor before catalytic converter, dynamic
response: slow response

Fault description
The diagnostic function monitors the dynamic response of
the oxygen sensor before the catalytic converter.

Condition for fault identification
Test condition:
The fault is recognized when closed-loop sensor reacts too
slowly to changes in the oxygen concentration within the
exhaust gas.
Potential problem source(s):
- Oxygen sensor before catalytic converter defective
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
- Drive at a constant speed between 50 and 80 km/h at
moderate rpm (1400 to 3240 rpm).
- No faults that would cause mixture faults are registered.

Condition for fault memory entry
The diagnostic fault code is logged when the fault remains
present for longer than 1 min.

Action in service
- Replace oxygen sensor before catalytic converter if fault
frequency is greater than 3

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 lamp lights up after 2nd driving cycle
- Higher exhaust emissions
- Higher fuel consumption
- Surge

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
Determine whether cylinder balancing is plausible; if not
plausible, perform cylinder balancing following repair