Condition for fault identification

Test condition:

The fault is recognized when an electrical malfunction is present in the oxygen sensor before the catalytic converter.

Potential problem source(s):

• Defective wiring harness
• Oxygen sensor before catalytic converter defective
• Defective DME

Terminal condition: none

Voltage condition:

• Onboard electrical system voltage between 9 V and 16 V

Temperature condition:

• Engine warmed to normal temp, above 80 °C

Time condition:

• Overrun operation must be present for at least 3 seconds and the EGR valve must be closed.

Other conditions:

• Engine on
• Vehicle underway
• Pre-catalyst oxygen sensor heated to adequate temperature
• Overrun mode