T8 / P0420 00
Read the instructions below then
start the fault diagnostic procedure.
Symptom: Fault indicator lamp (for further information see WIS Fault diagnosis, general)
Three Way Catalytic Converter. Malfunction.
Fault symptom
Fault indicator lamp (for further information see WIS Fault diagnosis, general)
On-board diagnosis
Type of diagnosis:
| Once per driving cycle. Stopped when fault criteria are fulfilled or OK reported. |
Enable criteria:
| Motor running for more than 230 s. |
| Accelerator pedal released. |
| Exhaust temperature between 400 and 750°C. |
| No DTC detected for oxygen sensors 1 and 2. |
| No DTC detected for the mass air flow sensor. |
| No DTCs detected for exhaust temperature sensor (applies if sensor is fitted and earlier software, MY 03). |
| Idling speed increased, idling speed stabilised through ignition reduction. |
| Closed loop delayed in rich mode until O2S2 shows rich. |
| Closed loop delayed in lean mode and time is measured until O2S2 shows lean. |
Fault criteria:
| Too short time to O2S2 shows lean, indicating that the catalytic converter's oxygen storing ability is poor. |
Dependent:
System reaction to a fault:
OK report:
| Diagnostics carried out without fault reported. |
Fault handling:
| (See section Fault handling III, "Other emission-related components and functions" for more information.) |
Diagnostic help
Diagnosis regards:
| Faulty catalytic converter. |
Functions in the diagnostic tool related to the fault:
| • | Catalytic converter temperature. |
