FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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H34 - Check For Open HO2S Heater Harness Circuit



- Key Off.

- Suspect sensor disconnected.

- Breakout box installed, PCM disconnected.

- Use the following chart to measure the resistance between the appropriate test pins at the breakout box and the HO2S heater harness connector.

HO2S-11 Test Pin 93 (Heater SIG)
HO2S-12 Test Pin 95 (Heater SIG)
HO2S-21 Test Pin 94 (Heater SIG)
HO2S-22 Test Pin 96 (Heater SIG)

- Is the resistance less 5.0 ohms?

YES -- OPEN heater circuit in the PCM. REPLACE PCM. REMOVE breakout box. RECONNECT all components. Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes

NO -- OPEN in the wiring harness. REPAIR open in harness. REMOVE breakout box. RECONNECT all components. Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes