Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. Only use this test to diagnose the following:

• HO2S and sensor connection.
• Vacuum systems.
• Fuel injector and/or fuel injector circuitry.
• Powertrain Control Module (PCM).
• Electrical circuits (HO2S, HO2S GND, INJ 1-8, VPWR and SIG RTN).

1) Check For Crossed HO2S Circuit  Turn ignition off. Disconnect suspect HO2S. Inspect connector for indication of crossed wires or incorrect installation. Repair or replace if necessary and repeat KOER self-test. If no faults are found, go to next step.

2)  Leave ignition off and suspect HO2S disconnected. Disconnect PCM 104-pin connector. Inspect connector for damaged pins, corrosion and loose wires. Repair circuit as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between suspect circuit terminal at wiring harness connector and corresponding test pin at breakout box. If resistance is less than 5 ohms, fault is intermittent and cannot be duplicated at this time. Repeat QUICK TEST to verify DTC is present. If resistance is 5 ohms or more, repair circuit. Clear PCM memory. Drive vehicle for 5 miles and repeat QUICK TEST.