Fault description

Diagnosis monitors the signal voltage of the oxygen sensor after catalytic converter after overrun mode.

The fault is detected when the signal gradient from lean to rich is less than a threshold.

Possible cause of fault:

• open circuit;
• short to B+, sensor stops (with help from a voltage source) at U > 0.2V;
• Sensor too cold after overrun fuel cutout (only possible in extreme situations)
• Impact through the catalyst in the case of critical fuel
• EGO sensor strongly altered