NOTE:
Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See HOW TO USE THIS MANUAL.)
1. Warm up the engine to normal operating temperature.
2. Using the M-MDS, monitor the following:
Vehicle speed (PID: VSS)
Engine speed (PID: RPM)
Front HO2S current (PID: O2S11)
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 front HO2S current (PID: O2S11) is 0.25 mA or more while decelerating as shown in the figure.
If not within the specification, inspect the front HO2S for an open or short circuit. (See FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION [LF].) Then if there is no malfunction in the wiring harness, replace the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [LF].)
1. Disconnect the front HO2S connector.
2. Measure the resistance between front HO2S terminals C and D.
If not within the specification, replace the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [LF].)
Front HO2S heater resistance
1—10 ohms
1. Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION [LF].)
2. Disconnect the front HO2S connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)
Open circuit
If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.
Front HO2S terminal A and PCM terminal 2AD
Front HO2S terminal B and PCM terminal 2Z
Front HO2S terminal C ignition relay
Front HO2S terminal D and PCM terminal 2BG
Short circuit
If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness.
Front HO2S terminal A and power supply
Front HO2S terminal A and body ground
Front HO2S terminal B and power supply
Front HO2S terminal B and body ground
Front HO2S terminal C and body ground
Front HO2S terminal D and power supply
Front HO2S terminal D and body ground