Diagnosis of electrical faults of the front oxygen sensor

P0130/P0150 

Lambda control can be disabled only when at least a pending fault code (service $07) has been entered in the fault code memory. Several operating conditions do exist, under which faulty components can be pinpointed only after a time delay. Lambda control must however be disabled when fault symptoms are detected.

This diagnostic function (which is identical for both banks) sets a general electrical fault. The actual fault which is accompanied by a second entry into the fault code memory is then pinpointed afterwards by the appropriate diagnostic function. This second fault entry could either be a sensor line error or a heater fault of the front oxygen sensor. In order to ensure timely MIL illumination (two-in-a-row principle) the general electrical fault is also set when a sensor line error or a heater fault of the front oxygen sensor is set.

A general electrical fault LSVE of the front oxygen sensor will be set when

either the internal resistance of its Nernst cell is implausibly high or its ceramic temperature is implausibly low.