Heated Oxygen Sensor Inspection

HEATED OXYGEN SENSOR (HO2S) INSPECTION

Inspection of Voltage

NOTE: Perform the following test only when directed.

1. Warm up the engine and idle it.




2. Disconnect the HO2S connector.
3. Connect a voltmeter between the HO2S connector terminal A and a GND.
4. Run the engine at 3,000 rpm until the voltmeter indicates 0 - 1.0 V.




5. Verify the voltage when engine speed is suddenly increased and decreased several times.
- If HO2S is okay, but PID value is out of specification, perform the "Circuit Open/Short Inspection".
- If not as specified, replace the HO2S.

6. Reconnect the HO2S connector.

Circuit Open/Short Inspection

Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- Heated oxygen circuit (HO2S connector terminal A and PCM connector terminal 4W (Front).)
- GND circuit (HO2S connector terminal B and PCM connector terminal 4O through common connector (Front).)
- Heated oxygen circuit (HO2S connector terminal A and PCM connector terminal 4AA (Rear).)
- GND circuit (HO2S connector terminal B and PCM connector terminal 4O through common connector (Rear).)

Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- HO2S connector terminal A and PCM connector terminal 4W to GND (Front).
- HO2S connector terminal A and PCM connector terminal 4AA to GND (Rear).