Chart C-1F - Oxygen Sensor Heater Check: Notes

Generator charging circuit supplies battery voltage to heater part of oxygen sensor. Heater warms oxygen sensor to allow a varying voltage to be produced by oxygen sensor.

1. This step will verify battery voltage is present for heater. Wire identified as Blue, HO2S signal circuit, could be Light Blue or Red/Blue.
2. This step checks ground circuit to heater.
3. This step checks heater element resistance.

Fig 1: Chart C-1F - Schematic

Courtesy of ISUZU MOTOR CO.

Fig 2: Chart C-1F - Diagnostic Flowchart

Courtesy of ISUZU MOTOR CO.