DTC Logic

DTC DETECTION 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 of the three way catalyst (manifold) causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the switching response of the sensor's voltage is faster than specified during the various driving condition such as fuel cut.

DTC CONFIRMATION PROCEDURE

1.INSPECTION START

Do you have CONSULT-III? Do you have CONSULT-III? YES >> GO TO 2.

NO >> GO TO 11.

2.PRECONDITIONING

NOTE

:
• If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds.

• For the best results, perform DTC WORK SUPPORT at a temperature of 0 to 30°C (32 to 86°F)
• “COMPLETED” will appear on CONSULT-III screen when all tests “COND1”, “COND2” and “COND3” are completed.

TESTING CONDITION:
Never stop engine during this procedure. If the engine is stopped, retry this procedure from PERFORM PROCEDURE FOR COND1-II.

>> GO TO 3.

3.PERFORM PROCEDURE FOR COND1-I

Start engine and warm it up to normal operating temperature.

>> GO TO 4.

4.PERFORM PROCEDURE FOR COND1-II

Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 5.

5.PERFORM PROCEDURE FOR COND1-III

1. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

2. Let engine idle for 1 minute.

3. Select “HO2S2 (B1) P0139” of “HO2S2” in “DTC WORK SUPPORT” mode with CONSULT-III.

4. Touch “START”.

5. Rev engine up to 2,000 rpm two or three times quickly under no load.

Is “COMPLETED” appears on CONSULT-III screen? YES >> GO TO 9.

NO >> GO TO 6.

6.PERFORM PROCEDURE FOR COND1-IV

When the following conditions are met, “TESTING” will be displayed at “COND1” on the CONSULT-III screen.

Maintain the condition continuously until “TESTING” changes to “COMPLETED”. (It will take approximately 60 seconds.)

Which is displayed on CONSULT-III screen? COND1: OUT OF CONDITION>>GO TO 4.

COND1: COMPLETED, COND2: INCOMPLETED>>GO TO 7.

COND1: COMPLETED, COND2: COMPLETED>>GO TO 8.

7.PERFORM PROCEDURE FOR COND2

While driving, release accelerator pedal completely from the above condition until “INCOMPLETED” at “COND2” on CONSULT-III screen has turned to “COMPLETED”. (It will take approximately 4 seconds.) Which is displayed on CONSULT-III screen? COND2: COMPLETED, COND3: INCOMPLETED>>GO TO 8.

COND2: COMPLETED, COND3: COMPLETED>>GO TO 9.

8.PERFORM PROCEDURE FOR COND3-I

Stop vehicle and let it idle until “INCOMPLETED” of “COND3” on CONSULT-III screen has turned to “COMPLETED”.

(It will take a maximum of approximately 6 minutes.) >> GO TO 9.

9.PERFORM PROCEDURE FOR COND3-II

Touch “SELF DIAGRESULTS”.

Which is displayed on CONSULT-III screen? YES >> INSPECTION END

NO >>Go to EC-631, "Diagnosis Procedure".

CAN NOT BE DIAGNOSED>>GO TO 10.

10.PERFORM PROCEDURE FOR COND3-III

1. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).

2. Turn ignition switch ON and select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-III.

3. Start engine and warm it up until “COOLAN TEMP/S” indication reaches to 70°C (158°F).

>> GO TO 5.

11.PREFORM COMPONENT FUNCTION CHECK

Perform Component Function Check. Refer to EC-631, "Component Function Check".

NOTE

:
Use Component Function Check to check the overall function of heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.

Is the inspection result normal?

YES >> INSPECTION END

NO >> Go to EC-631, "Diagnosis Procedure".

Component Function Check

1.PERFORM COMPONENT FUNCTION CHECK-I

Without CONSULT-III

1. Start engine and warm it up to 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. Check the voltage between ECM harness connector and ground under the following condition.

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 2.

2.PERFORM COMPONENT FUNCTION CHECK-II

Check the voltage between ECM harness connector and ground under the following condition.

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 3.

3.PERFORM COMPONENT FUNCTION CHECK-III

Check the voltage between ECM harness connector and ground under the following condition.

Is the inspection result normal? YES >> INSPECTION END

NO >> Go to EC-631, "Diagnosis Procedure".

Diagnosis Procedure

1.CHECK GROUND CONNECTION

1. Turn ignition switch OFF.

2. Check ground connection E38. Refer to Ground Inspection in GI-44, "Circuit Inspection".

Is the inspection result normal? YES >> GO TO 2.

NO >> Repair or replace ground connection.

2.CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE

1. Clear the mixture ratio self-learning value. Refer to EC-546, "Work Procedure".

2. Run engine for at least 10 minutes at idle speed.

Is the 1st trip DTC P0171 or P0172 detected? Is it difficult to start engine? YES >> Perform trouble diagnosis for DTC P0171 or P0172. Refer to EC-635, "DTC Logic" or EC-639, "DTC Logic".

NO >> GO TO 3.

3.CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect heated oxygen sensor 2 (HO2S2) harness connector.

3. Disconnect ECM harness connector.

4. Check the continuity between HO2S2 harness connector and ECM harness connector.

5. Also check harness for short to ground and short to power.

Is the inspection result normal? YES >> GO TO 4.

NO >> 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 the continuity between HO2S2 harness connector and ECM harness connector.

2. Check the continuity between HO2S2 harness connector or ECM harness connector and ground.

3. Also check harness for short to power.

Is the inspection result normal? YES >> GO TO 5.

NO >> Repair open circuit or short to ground or short to power in harness or connectors.

5.CHECK HEATED OXYGEN SENSOR 2

Refer to EC-633, "Component Inspection".

Is the inspection result normal? YES >> GO TO 6.

NO >> Replace heated oxygen sensor 2.

6.CHECK INTERMITTENT INCIDENT

Refer to GI-42, "Intermittent Incident".

>> INSPECTION END

Component Inspection

1.INSPECTION START

Do you have CONSULT-III? Do you have CONSULT-III? YES >> GO TO 2.

NO >> GO TO 3.

2.CHECK HEATED OXYGEN SENSOR 2

With CONSULT-III

1. Turn ignition switch ON and select “ENGINE” using CONSULT-III.

2. Select “DATA MONITOR” mode.

3. Start engine and warm it up to the normal operating temperature.

4. Turn ignition switch OFF and wait at least 10 seconds.

5. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

6. Let engine idle for 1 minute.

7. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select “HO2S2 (B1)” as the monitor item with CONSULT-III.

8. Check “HO2S2 (B1)” at idle speed when adjusting “FUEL INJECTION” to ±25%.

“HO2S2 (B1)” should be above 0.68 V at least once when the “FUEL INJECTION” is +25%.

“HO2S2 (B1)” should be below 0.36 V at least once when the “FUEL INJECTION” is −25%.

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 6.

3.CHECK HEATED OXYGEN SENSOR 2-I

Without CONSULT-III

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. Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 4.

4.CHECK HEATED OXYGEN SENSOR 2-II

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 5.

5.CHECK HEATED OXYGEN SENSOR 2-III

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 6.

6.REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning 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 (commercial service tool) and approved anti-seize lubricant (commercial service tool).

>> INSPECTION END