HF5 - Check Rear HO2S Wiring

*** THIS ARTICLE REFLECTS CHANGES MADE BY TSB # 9326B7, December 1993

NOTE: If the electrical connections of the rear HO2S are interchanged/crossed, the Catalyst Efficiency Monitor Test will be failed.

- Inspect the wiring of each rear HO2S for proper routing and connection.

- Are the HO2S wires improperly routed or connected?

YES -- Correctly route/connect the rear HO2S harness circuit(s). COMPLETE the PCM reset to clear all DTCs. Clearing Diagnostic Trouble Codes

Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes

NO -- No EEC-V root causes related to the DTCs. GO to HF6. HF6 - Check Fuel Pressure