Component Tests and General Diagnostics
HEATED OXYGEN SENSOR (HO2S) INSPECTIONHO2S Voltage Inspection
NOTE: Perform the following inspection only when directed.
1. Warm up the engine and idle it
2. Disconnect the HO2S connector
3. Connect the voltmeter test leads to the following HO2S terminals:
- HO2S (front and rear)
- (+) lead-terminal A
- (-) lead-terminal B
4. With the vehicle stopped, run the engine at 3,000 rpm until the voltmeter moves between 0.5 and 0.7 V.
5. Verify that the measurement voltage changes when the engine speed increases and decreases suddenly several times.
- If not as specified, replace the HO2S
- If the HO2S is okay, but PIDs value are out of specification, perform the "Circuit Open/Short Inspection".
Circuit Open/Short Inspection (Sensor)
1. Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION.)
2. Inspect the following wiring harnesses for open or short circuit. (Continuity check).
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness. Front
- HO2S terminal A (harness-side) and PCM terminal 1AB (harness-side)
- HO2S terminal B (harness-side) and PCM terminal 2H (harness-side) Rear
- HO2S terminal A (harness-side) and PCM terminal 1Y (harness-side)
- HO2S terminal B (harness-side) and PCM terminal 2H (harness-side)
Short circuit
- If there is continuity, there is a short circuit Repair or replace the wiring harness. Front and Rear
- HO2S terminal A (harness-side) and body GND
- HO2S terminal A (harness-side) and power supply
- HO2S terminal B (harness-side) and power supply
HO2S Heater Resistance Inspection
1. Disconnect the HO2S connector.
2. Measure the resistance between the HO2S terminals C and D.
- If not as specified, replace the HO2S.
- If the HO2S heater is okay, but PID value is out of specification, perform the "Circuit Open/Short Inspection".
Specification
Front: 3.0 - 3.6 ohms
Rear: 5 - 7 ohms
Circuit Open/Short Inspection (Heater)
1. Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION.)
2. Inspect the following wiring harnesses for open or short circuit. (Continuity check).
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
Front
- HO2S terminal C (harness-side) and main relay terminal C (harness-side)
- HO2S terminal D (harness-side) and PCM terminal 4A (harness-side)
Rear
- HO2S terminal C (harness-side) and main relay terminal C (harness-side)
- HO2S terminal D (harness-side) and PCM terminal 4D (harness-side)
Short circuit
- If there is no continuity, there is a short circuit. Repair or replace the wiring harness.
Front and rear
- HO2S terminal C (harness-side) and body GND
- HO2S terminal D (harness-side) and power supply
- HO2S terminal D (harness-side) and body GND