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Oxygen Sensor: Testing and Inspection

HEATED OXYGEN SENSOR (HO2S) INSPECTION[L3]

California Emission Regulation Applicable ATX Model

NOTE: Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See FOREWORD[L3].)

Front HO2S current inspection
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: 02S11)

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: 02S11) is 0.25 mA or more while decelerating as shown in the figure.
- If not within the specification, inspect the HO2S for an open or short circuit. (See Front HO2S circuit open/short inspection (sensor).) Then if there is no malfunction in the wiring harness, replace the front HO2S.

Front HO2S heater resistance inspection
1. Disconnect the front HO2S connector




2. Measure the resistance between front H02S terminals C and D.
- If not within the specification, replace the front HO2S.

Front HO2S heater resistance: 1-10 ohms

Front HO2S circuit open/short inspection (sensor)
1. Disconnect the PCM connector.
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 and PCM terminal 2BG
- Front HO2S terminal D and ignition switch

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 body ground
- Front HO2S terminal A and power supply
- Front HO2S terminal B and body ground
- Front HO2S terminal B and power supply
- Front HO2S terminal D and body ground

Middle/rear HO2S voltage inspection
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)
- Middle/rear HO2S voltage (PID: 02S12102S13)

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 middle/rear HO2S outputs a voltage of 0.6 V or more, one time or more, then verify that the middle/rear HO2S voltage (PID: 02S1 2/02S13) 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. (See Middle/rear HO2S circuit open/short inspection (sensor).) Then if there is no malfunction in the wiring harness, replace the middle/rear HO2S.




Middle/rear HO2S circuit open/short inspection (sensor)
1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- Middle HO2S terminal A and PCM terminal 2R
- Middle HO2S terminal B and PCM terminal 1BG
- Rear HO2S terminal A and PCM terminal 2Q
- Rear HO2S terminal B and PCM terminal 1BC

Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- Middle/rear HO2S terminal A and body GND
- Middle/rear HO2S terminal A and power supply
- Middle/rear HO2S terminal B and power supply

Middle/rear HO2S heater resistance inspection
1. Disconnect the middle/rear HO2S connector.




2. Measure the middle/rear HO2S resistance between terminals C and D.
- If not within the specification, replace the HO2S.

Middle/rear HO2S heater resistance: 2-50 ohms

Middle/rear HO2S circuit open/short inspection (heater)




1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- Middle HO2S terminal C and ignition switch
- Middle HO2S terminal D and PCM terminal 2BF
- Rear HO2S terminal C and ignition switch
- Rear HO2S terminal D and PCM terminal 2BE

Short circuit
- If there is no continuity, there is a short circuit. Repair or replace the wiring harness.

Middle and rear
- Middle/rear HO2S terminal C and body GND
- Middle/rear HO2S terminal D and power supply
- Middle/rear HO2S terminal D and body GND

Except for California Emission Regulation Applicable ATX Model

NOTE: Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart.

Front HO2S current inspection
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: 02S11)

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: 02S11) is 0.25 mA or more while decelerating as shown in the figure.
- If not within the specification, inspect the H02S for an open or short circuit. (See Front HO2S circuit open/short inspection (sensor).) Then if there is no malfunction in the wiring harness, replace the front H02S

Front HO2S heater resistance inspection
1. Disconnect the front HO2S connector.




2. Measure the resistance between front HO2S terminals 2B and 2D.
- If not within the specification, replace the front HO2S.
Front HO2S heater resistance: 1-10 ohms

Front HO2S circuit open/short inspection (sensor)
1. Disconnect the PCM connector.
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 H028 terminal 1A and PCM terminal 2AD
- Front HO2S terminal 1B and PCM terminal 2AC
- Front HO2S terminal 1C and PCM terminal 2Z
- Front HO2S terminal 2B and main relay terminal C
- Front HO2S terminal 2D 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 1A and body ground
- Front HO2S terminal 1A and power supply
- Front HO2S terminal 1B and body ground
- Front HO2S terminal 1B and power supply
- Front HO2S terminal 1C and body ground
- Front HO2S terminal 1C and power supply
- Front HO2S terminal 2B and body ground
- Front HO2S terminal 2B and power supply
- Front HO2S terminal 2D and body ground
- Front HO2S terminal 2D and power supply

Rear HO2S voltage inspection
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)
- Rear HO2S voltage (PID: 02S12)
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 rear HO2S outputs a voltage of 0.6 V or more, one time or more, then verify that the rear HO2S voltage (PID: 02S12) 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. (See Rear HO2S circuit open/short inspection (sensor).) Then if there is no malfunction in the wiring harness, replace the rear HO2S.




Rear HO2S circuit open/short inspection (sensor)
1. Disconnect the PCM connector.
2. Disconnect the rear HO2S connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- Rear HO2S terminal A and PCM terminal 2Q
- Rear HO2S terminal B and PCM terminal 1BC

Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- Rear HO2S terminal A and body ground
- Rear HO2S terminal A and power supply
- Rear HO2S terminal B and power supply

Rear HO2S heater resistance inspection
1. Disconnect the rear HO2S connector.




2. Measure the rear HO2S resistance between terminals C and D.
- If not within the specification, replace the HO2S.

Rear HO2S heater resistance: 2-50 ohms

Rear H02S circuit open/short inspection (heater)




1. Disconnect the PCM connector.
2. Disconnect the rear HO2S connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- Rear H02S terminal C and ignition switch
- Rear H02S terminal D and PCM terminal 2BE

Short circuit
- If there is no continuity, there is a short circuit. Repair or replace the wiring harness.

Rear
- Rear H02S terminal C and body ground
- Rear H02S terminal D and power supply
- Rear HO2S terminal D and body ground
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