Heated Oxygen Sensor (HO2S) Heater Inspection

HEATED OXYGEN SENSOR (HO2S) HEATER INSPECTION

NOTE: Perform the following inspection only when directed.

Resistance Inspection
1. Disconnect the negative battery cable.
2. Disconnect the HO2S connector.




3. Measure the resistance between the HO2S terminals C and D using an ohmmeter
- If the HO2S heater is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection"
- If not as specified replace the HO2S (See EXHAUST SYSTEM REMOVAL/INSTALLATION)

Specification:
HO2S (RF,LF): 3.0 - 3.6 Ohms (20 °C (68 °F))
HO2S (RR,LR): 5.0 - 7.0 Ohms (20 °C (68 °F))

Circuit Open/Short Inspection

1. Disconnect the PCM connector (See PCM REMOVAL/INSTALLATION)




2. Inspect the following harness for open or short circuit (Continuity check).

Open circuit
- HO2S (RF) terminal C (harness-side) and ignition switch
- HO2S (RF) terminal D (harness-side) and PCM terminal 93 (harness-side)
- HO2S (LF) terminal C (harness-side) and ignition switch
- HO2S (LF) terminal D (harness-side) and PCM terminal 94 (harness-side)
- HO2S (RR) terminal C (harness-side) and ignition switch
- HO2S (RR) terminal D (harness-side) and PCM terminal 95 (harness-side)
- HO2S (LR) terminal C (harness-side) and ignition switch
- HO2S (LR) terminal D (harness-side) and PCM terminal 96 (harness-side)

Short circuit
- HO2S (RF) terminal C (harness-side) and body GND.
- HO2S (RF) terminal D (harness-side) and power supply.
- HO2S (RF) terminal D (harness-side) and body GND.
- HO2S (LF) terminal C (harness-side) and body GND.
- HO2S (LF) terminal D (harness-side) and power supply.
- HO2S (LF) terminal D (harness-side) and body GND.
- HO2S (RR) terminal C (harness-side) and body GND.
- HO2S (RR) terminal D (harness-side) and power supply.
- HO2S (RR) terminal D (harness-side) and body GND.
- HO2S (LR) terminal C (harness-side) and body GND.
- HO2S (LR) terminal D (harness-side) and power supply.
- HO2S (LR) terminal D (harness-side) and body GND.