H80 - DTCs 0136, 0156, 1137, 1138, 1157, 1158

DTC 0136 and 0156 indicate the output voltage of the downstream HO2S is within some calibratable functional window. KOER DTCs 1137, 1138, 1157 and 1158 can only be retrieved during KOER Self-Test when the fuel control is ramped rich and lean and monitored for a voltage change on the downstream HO2S.

Possible Causes:

- Wiring Concerns
- Pinched, shorted, and corroded wiring and pins.
- Crossed sensor wires

- Other Concerns
- Exhaust leaks
- Contaminated or defective sensor

- Are many of the above concerns present?

YES -- SERVICE as necessary. COMPLETE PCM reset to clear DTCs. COMPLETE a HO2S monitor drive cycle.

NO -- Go to H81. H81 - Check For KOER DTCs 1137, 1138, 1157, or 1158