ME9 / P2231 00
Read the instructions below then
start the fault diagnostic procedure.
Symptom: Malfunction Indicator Lamp
O2S 1 Signal Circuit Short to Heater Circuit
Fault symptom
Malfunction Indicator Lamp
On-board diagnosis
Type of diagnosis:
Enable criteria:
| Battery voltage should be between 10.7 and 18 Volts. |
| Engine speed exceeds 1800 rpm. |
| Sensor in normal operating range (715°C and up). |
| PWM signal of preheating circuit between 20 and 80%. |
| NONE of the following DTCs must be detected: |
Fault criteria:
| Voltage signal across Nernst cell changes more than 100 mV when preheating works on/off. One or more control module pins (3, 19, 35 or 52) is short circuited to the preheating circuit. |
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:
| • | Short Term Fuel Trim Status |
| (See also description of readings/activations in diagnostic tool) |
