Oxygen Sensor: Testing and Inspection
HEATED OXYGEN SENSOR (HO2S) INSPECTIONHO2S (Front and Rear) Voltage Inspection
NOTE: Perform the following test only when directed.
1. Warm up the engine and run it at idle.
2. Disconnect the HO2S (Front or Rear) connector.
3. Connect the voltmeter test leads to the following HO2S terminals:
- (+) lead-HO2S terminal A
- (-) lead-HO2S terminal B
4. Run the engine at 3,000 rpm until the voltmeter indicates approx. 0 - 1.0 V.
Specifications:
5. Verify that the voltmeter needle moves when the engine speed increases and decreases suddenly several times.
- If not as specified, replace the HO2S.
- If the HO2S is okay, but PID value or PCM terminal 60 (Front), 35 (Rear) voltage are out of specification, carry out the "Circuit Open/Short Inspection".
Circuit Open/Short Inspection
1. Remove the PCM.
2. Connect the SST (104 Pin Breakout Box) to the PCM as shown.
3. Tighten the connector attaching screw.
Tightening torque
7.9 - 10.7 N.m {80 - 110 kgf.cm, 69.5 - 95.4 in.lbf}
4. Inspect for an open or short circuit in the following wiring harnesses by probing the applicable sensor and SST (104 Pin Breakout Box) terminals with ohmmeter leads.
- If there is an open or short circuit, repair or replace wiring harnesses.
- If there is no open or short circuit, replace the HO2S.
Open circuit
- HO2S signal circuit (HO2S connector terminal A and PCM connector terminal 60 (Front), 35 (Rear))
- GND circuit (HO2S connector terminal B and PCM connector terminal 91
Short circuit
- HO2S signal circuit (HO2S terminal A and PCM connector terminal 60 (Front), 35 (Rear) to GND)
5. Reconnect the HO2S connector.
HO2S Heater (Front and Rear) Resistance Inspection
1. Disconnect the HO2S (Front or Rear) connector.
2. Measure the resistance between HO2S terminals C and D using an ohmmeter.
- If not as specified, replace the HO2S.
- If the HO2S heater is okay, but PID value or PCM terminal 94 (Front), 93 (Rear) voltage are out of specification, carry out the "Circuit Open/Short Inspection".
Specification
Front: Approx. 5.6 Ohms
Rear: Approx. 15.7 Ohms
Circuit Open/Short Inspection
1. Remove the PCM.
2. Connect the SST (104 Pin Breakout Box) to the PCM as shown.
3. Tighten the connector attaching screw.
Tightening torque
7.9 - 10.7 N.m {80 - 110 kgf.cm, 69.5 - 95.4 in.lbf}
4. Inspect for an open or short circuit in the following wiring harnesses by probing the applicable sensor and SST (104 Pin Breakout Box) terminals with ohmmeter leads.
- If there is an open or short circuit, repair or replace wiring harnesses.
- If there is no open or short circuit, replace the HO2S.
Open circuit
- Control circuit (HO2S connector terminal C and ignition switch (IG1) circuit through common connector)
- GND circuit (HO2S connector terminal D and PCM connector terminal 94 (Front), 93 (Rear))
Short circuit
- Control circuit (HO2S connector terminal C and ignition switch (IG1) circuit through common connector to GND)
- GND circuit (HO2S connector terminal D and PCM connector terminal 94 (Front), 93 (Rear) to GND)
5. Reconnect the HO2S connector.