Heated Oxygen Sensor Diagnostics
The front heated oxygen sensor is of the linear type and works with current control. That is why it is not possible to measure the signals from the heated oxygen sensor with a multimeter. The rear heated oxygen sensor is of the binary type and functions as earlier heated oxygen sensors. The engine control module (ECM) checks the heated oxygen sensors when conditions for diagnostics have been fulfilled.
The following faults can be registered by the control module:
- Electrical faults in circuits for the actual heated oxygen sensors (HO2S) and in their preheating
- Adaptation. The control module checks that the long-term fuel trim is not higher or lower than the pre-defined values
- Heated oxygen sensor dynamics. The control module checks that the switch time between rich and lean mixture is not too long.
For further information about diagnostics for the heated oxygen sensor, see "Diagnostic trouble code (DTC) information" in appropriate diagnostics tool, information manager.