Ignition "ON" & Engine "OFF"

Monitor the O2 SNSR VOL.-B1/S1 parameter on the Scantool data list while wiggling the wiring harness and related connectors.

The value should remain more or less unchanged. If not, check for the following conditions:

-Check for corrosion on terminals

-Check for terminal tension ( at the HO2S and at the ECM)

-Check for damaged wiring

-Check the HO2S ground circuit for a good connection

-Check the 15A sensor2 fuse

-Check front and rear HO2S for connections being reversed.

Was a problem found in any of the above areas?

YES

▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure

NO

▶ Go to next step as below