Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

J26 - Check HO2S Circuit For Short to Power



HOS2 Connector:






- Key "OFF".

- Left or front Heated Oxygen Sensor (HO2S) disconnected.

- Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary. Leave PCM disconnected.

- Key "ON".

- Measure voltage between the HO2S signal at the HO2S vehicle harness connector and chassis ground.

- Is voltage less than 2.0 volts?

Yes -- Replace PCM. Reconnect HO2S. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

No -- Service short circuit. Reconnect PCM and HO2S. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

Clear Keep Alive Memory. Clearing Keep Alive Memory (KAM) and Relearn Procedure