Component Tests and General Diagnostics

HEATED OXYGEN SENSOR (HO2S) INSPECTION [AJ]

NOTE: Perform the following test only when directed.

HO2S Voltage Inspection

1. Warm up the engine to normal operating temperature.
2. Using the WDS or equivalent, monitor the following:
- Vehicle speed (PID: VSS)
- Engine speed (PID: RPM)
- HO2S voltage (PID: O2S11, O2S12, O2S21, O2S22)

3. Drive the vehicle and decelerate the engine speed by releasing the accelerator pedal fully when the engine speed is 3,000 rpm or more.

4. Verify that the HO2S outputs a voltage of 0.6 V or more, one time or more, then verify that the HO2S voltage (PID: O2S11, O2S12, O2S21, O2S22) is 0.3 V or less while decelerating as shown in the figure.
- If not within the specification, inspect the HO2S for an open or short circuit. Then if there is no malfunction in the wiring harness, replace the HO2S.

HO2S Circuit Open/Short Inspection

1. Disconnect the PCM connector.

2. Connect the SST (104 Pin Breakout Box) with the PCM disconnected.
3. Tighten the connector attaching bolt.

Tightening torque: 3.0-5.4 N.m {30-56 kgf.cm, 27-48 in.lbf}

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

Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- HO2S (Front, RH) terminal A (harness-side) and 104 pin breakout box terminal 18
- HO2S (Front, RH) terminal B (harness-side) and 104 pin breakout box terminal 20
- HO2S (Rear, RH) terminal A (harness-side) and 104 pin breakout box terminal 44
- HO2S (Rear, RH) terminal B (harness-side) and 104 pin breakout box terminal 20
- HO2S (Front, LH) terminal A (harness-side) and 104 pin breakout box terminal 19
- HO2S (Front, LH) terminal B (harness-side) and 104 pin breakout box terminal 20
- HO2S (Rear, LH) terminal A (harness-side) and 104 pin breakout box terminal 45
- HO2S (Rear, LH) terminal B (harness-side) and 104 pin breakout box terminal 20

Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- HO2S (Front, RH) terminal A (harness-side) and body ground
- HO2S (Front, RH) terminal A (harness-side) and power supply
- HO2S (Front, RH) terminal B (harness-side) and power supply
- HO2S (Rear, RH) terminal A (harness-side) and body ground
- HO2S (Rear, RH) terminal A (harness-side) and power supply
- HO2S (Rear, RH) terminal B (harness-side) and power supply
- HO2S (Front, LH) terminal A (harness-side) and body ground
- HO2S (Front, LH) terminal A (harness-side) and power supply
- HO2S (Front, LH) terminal B (harness-side) and power supply
- HO2S (Rear, LH) terminal A (harness-side) and body ground
- HO2S (Rear, LH) terminal A (harness-side) and power supply
- HO2S (Rear, LH) terminal B (harness-side) and power supply

HO2S Heater Resistance Inspection

1. Disconnect the HO2S (front or rear) connector.
2. Measure the resistance between the following HO2S terminals.
- HO2S (Front, RH) and HO2S (Rear, RH)
- Terminal C and D

- HO2S (Front, LH) and HO2S (Rear, LH)
- Terminal C and D

- If not as specified, replace the HO2S.
- If the HO2S heater is okay, but PID value or any of PCM terminal 57, 58, 83, 84 voltage are out of specification, perform the "Circuit Open/Short Inspection".

Specification:
Front (RH, LH): 2-50 ohms
Rear (RH, LH): 2-50 ohms

Circuit Open/Short Inspection

1. Disconnect the PCM connector.

2. Connect the SST (104 Pin Breakout Box) with the PCM disconnected.
3. Tighten the connector attaching bolt.

Tightening torque: 3.0-5.4 N.m {30-56 kgf.cm, 27-48 in.lbf}