T8 / P0138 00
Read the instructions below then
start the fault diagnostic procedure.
Symptom: Fault indicator lamp (for further information see WIS Fault diagnosis, general)
O2S Circuit. High Voltage. Sensor 2.
Fault symptom
Fault indicator lamp (for further information see WIS Fault diagnosis, general)
On-board diagnosis
Type of diagnosis:
Enable criteria:
| Battery voltage must be between 11 - 16 V. |
| Engine running (with at least 7700 combustions). |
| Preheating active for more than 4 s. |
| Secondary air pump not active, if fitted. |
| EVAP, leak diagnosis inactive (if OBD II). |
Fault criteria:
| When voltage across the sensor is more than 1200 mV for 5 s. |
Dependent:
System reaction to a fault:
| Preheating is switched off. |
| Adaption of rear oxygen sensor is blocked and reset. |
OK report:
| Fault criteria NOT fulfilled for 6 s. |
Fault handling:
| (See section Fault handling III, "Other emission-related components and functions" for more information.) |
Checking the wiring harness
Move the wiring harness at several spots and in several directions to reveal intermittent breaks and short-circuits. Check switches, connectors and crimp connections for oxidation, retracted pins and pin clamping force.
Diagnostic help
Diagnosis regards:
| Electrical fault in connecting leads or component. |
Functions in the diagnostic tool related to the fault:
| (See also description of readings/activations in diagnostic tool) |
