Engine Controls Except For California

DTC P0138 HO2S2

Component Description

The heated oxygen sensor 2, after three way catalyst (manifold), monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air/fuel ratio is controlled to stoichiometric, by the signal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1 V in richer conditions to 0 V in leaner conditions.
Under normal conditions the heated oxygen sensor 2 is not used for engine control operation.

CONSULT Reference Value in Data Monitor Mode

Specification data are reference values.

On Board Diagnosis Logic

The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/
F) sensor 1. The oxygen storage capacity before the three way catalyst (manifold) causes the longer switching time.

MALFUNCTION A

To judge the malfunctions of rear heated oxygen sensor 2, ECM
monitors whether the voltage is unusually high during the various driving condition such as fuel-cut.

MALFUNCTION B

To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the minimum voltage of sensor is sufficiently low during the various driving condition such as fuel-cut.

DTC Confirmation Procedure

Perform PROCEDURE FOR MALFUNCTION A first.
If DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.

PROCEDURE FOR MALFUNCTION A

With CONSULT
1.Turn ignition switch ON and select "DATA MONITOR" mode with CONSULT.
2.Start engine and warm it up to the normal operating temperature.
3.Turn ignition switch OFF and wait at least 10 seconds.
4.Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
5.Let engine idle for 2 minutes.
6.Check 1st trip DTC.
7.If 1st trip DTC is detected, go to .
With GST
Follow the procedure "With CONSULT" above.

PROCEDURE FOR MALFUNCTION B

With CONSULT
TESTING CONDITION:
For the best results, perform DTC WORK SUPPORT at a temperature of 0 to 30�C (32 to 86�F).
1.Turn ignition switch ON and select "DATA MONITOR " mode with CONSULT
2. Start engine and warm it up to the normal operating temperature.
3.Turn ignition switch OFF and wait at least 10 seconds.
4.Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
5.Let engine idle for 1 minute.
6.Make sure that "COOLAN TEMP/S" indicates more than 70�C (158�F).
If not, warm up engine and go to next step when "COOLAN TEMP/S" indication reaches to 70�C (158�F).
7.Open engine hood.
8.Select "HO-2S2 (B1) P1146" (for DTC P0138) of "HO-2S2" in "DTC WORK SUPPORT" mode with CONSULT.
9.Following the instruction of CONSULT.
NOTE:
It will take at most 10 minutes until "COMPLETED" is displayed.
10.Make sure that "OK" is displayed after touching "ON-BOARD DIAGNOSIS".
If "NG" is displayed, .
If "CAN NOT BE DIAGNOSED" is displayed, perform the following.
a.Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
b.Return to step 1.

Overall Function Check

PROCEDURE FOR MALFUNCTION B

Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.
With GST
1.Start engine and warm it up to the normal operating temperature.
2.Turn ignition switch OFF and wait at least 10 seconds.
3.Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4.Let engine idle 1 minute.
5.Set voltmeter probes between ECM terminal 50 (HO-2S2 signal) and ground.

6.Check the voltage when revving up to 4,000 rpm under no load at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
The voltage should be below 0.18 V at least once during this procedure.
If the voltage can be confirmed in step 6, step 7 is not necessary.
7.Keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D
position (CVT) or 3rd gear position (M/T).
The voltage should be below 0.18 V at least once during this procedure.
8.If NG, go to .

Wiring Diagram

Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT.

CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

Diagnosis Procedure

PROCEDURE FOR MALFUNCTION A

1. CHECK GROUND CONNECTIONS

1.Turn ignition switch OFF.

1.Disconnect heated oxygen sensor 2 harness connector (2).
-White arrow indicates : Vehicle front
-Heated oxygen sensor 2 (1)
2.Disconnect ECM harness connector.
3.Check harness continuity between ECM terminal 59 and HO-2S2
terminal 1. Refer to Wiring Diagram.
Continuity should exist.
4.Also check harness for short to ground and short to power.
OK or NG
OK- GO TO 4.
NG- GO TO 3.

3. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E3, F2
- Harness for open circuit or short between heated oxygen sensor 2 and ECM.
- Repair open circuit or short to ground or short to power in harness or connectors.

4. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.Check harness continuity between ECM terminal 50 and HO-2S2 terminal 4.
Refer to Wiring Diagram.
Continuity should exist.
2.Check harness continuity between ECM terminal 50 or HO-2S2 terminal 4 and ground.
Refer to Wiring Diagram.
Continuity should not exist.
3.Also check harness for short to power.
OK or NG
OK- GO TO 6.
NG- GO TO 5.

5. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E3, F2
- Harness for open circuit or short between heated oxygen sensor 2 and ECM.
- Repair open circuit or short to ground or short to power in harness or connectors.

6. CHECK HO2S2 CONNECTOR FOR WATER

Check connectors for water.
Water should not exist.
OK or NG
OK- GO TO 7.
NG- Repair or replace harness or connectors.

7. CHECK HEATED OXYGEN SENSOR 2

.
OK or NG
OK- GO TO 8.
NG- Replace heated oxygen sensor 2.

8. CHECK INTERMITTENT INCIDENT

Refer to Initial Inspection and Diagnostic Overview
-INSPECTION END

PROCEDURE FOR MALFUNCTION B

1. CHECK GROUND CONNECTIONS

1.Turn ignition switch OFF.

2.Loosen and retighten engine screws on the body.
Except For California.
-White arrow indicates : Vehicle front
-Body ground (1)
OK or NG
OK- GO TO 2.
NG- Repair or replace ground connections.

2. CLEAR THE SELF-LEARNING DATA

With CONSULT
1.Start engine and warm it up to normal operating temperature.
2.Select "SELF-LEARNING CONT" in "WORK SUPPORT" mode with CONSULT.
3.Clear the self-learning control coefficient by touching "CLEAR".
4.Run engine for at least 10 minutes at idle speed.
Without CONSULT
1.Start engine and warm it up to normal operating temperature.
2.Turn ignition switch OFF.

3.Disconnect mass air flow sensor (1) harness connector, and restart and run engine for at least 5 seconds at idle speed.
4.Stop engine and reconnect mass air flow sensor harness connector.
5.Make sure that DTC P0102 is displayed.
6.Erase the DTC memory. Emission-Related Diagnostic Information Except For California.
7.Make sure that DTC P0000 is displayed.
8.Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0172 detected? Is it difficult to start engine?
YES- Perform trouble diagnosis for DTC P0172.
NO- GO TO 3.

3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1.Turn ignition switch OFF.

2.Disconnect heated oxygen sensor 2 harness connector (2).
-White arrow indicates : Vehicle front
-Heated oxygen sensor 2 (1)
3.Disconnect ECM harness connector.
4.Check harness continuity between ECM terminal 59 and HO-2S2
terminal 1. Refer to Wiring Diagram.
Continuity should exist.
5.Also check harness for short to ground and short to power.
OK or NG
OK- GO TO 5.
NG- GO TO 4.

4. CHECK MALFUNCTIONING PART

Check the following.
- Harness connectors E3, F2
- Harness for open circuit or short between heated oxygen sensor 2 and ECM.
- Repair open circuit or short to ground or short to power in harness or connectors.

5. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.Check harness continuity between ECM terminal 50 and HO-2S2 terminal 4.
Refer to Wiring Diagram.
Continuity should exist.
2.Check harness continuity between ECM terminal 50 or HO-2S2 terminal 4 and ground.
Refer to Wiring Diagram.
Continuity should not exist.
3.Also check harness for short to power.
OK or NG
OK- GO TO 7.
NG- GO TO 6.

6. CHECK MALFUNCTIONING PART

Check the following.
- Harness connectors E3, F2
- Harness for open circuit or short between heated oxygen sensor 2 and ECM.
- Repair open circuit or short to ground or short to power in harness or connectors.

7. CHECK HEATED OXYGEN SENSOR 2

.
OK or NG
OK- GO TO 8.
NG- Replace heated oxygen sensor 2.

8. CHECK INTERMITTENT INCIDENT

Refer to Initial Inspection and Diagnostic Overview
-INSPECTION END

Component Inspection

HEATED OXYGEN SENSOR 2

With CONSULT
1.Start engine and warm it up to the normal operating temperature.
2.Turn ignition switch OFF and wait at least 10 seconds.
3.Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4.Let engine idle for 1 minute.
5.Select "FUEL INJECTION" in "ACTIVE TEST" mode, and select "HO-2S2 (B1)" as the monitor item with
CONSULT.
6.Check "HO-2S2 (B1)" at idle speed when adjusting "FUEL INJECTION" to �25%.

"HO-2S2 (B1)" should be above 0.68 V at least once when the "FUEL INJECTION" is +25%.
"HO-2S2 (B1)" should be below 0.18 V at least once when the "FUEL INJECTION" is 25%.

CAUTION:
- Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor
Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT
1.Start engine and warm it up to the normal operating temperature.
2.Turn ignition switch OFF and wait at least 10 seconds.
3.Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4.Let engine idle for 1 minute.
5.Set voltmeter probes between ECM terminal 50 (HO-2S2 signal) and ground.

6.Check the voltage when revving up to 4,000 rpm under no load at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
The voltage should be above 0.68 V and below 0.18 V at least once during this procedure.
If the voltage can be confirmed at step 6, step 7 is not necessary.
7.Keep vehicle idling for 10 minutes, then check voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D position (CVT) or 3rd gear position (M/T).
The voltage should be above 0.68 V and below 0.18 V at least once during this procedure.
8.If NG, replace heated oxygen sensor 2.

CAUTION:
- Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor
Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.