Nissan Altima (L32) 2007-2012 Service Manual: P0146 HO2S3

Description

The heated oxygen sensor 3, after HC adsorption catalyst (Under floor), monitors the oxygen level in the exhaust gas on each bank.

This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions.

Under normal conditions the heated oxygen sensor 3 is not used for engine control operation.

DTC Logic

DTC DETECTION LOGIC

The heated oxygen sensor 3 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 3, ECM monitors whether the voltage is unusually high during the various driving condition such as fuel-cut.

DTC CONFIRMATION PROCEDURE

1.PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.

>> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDURE

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

2. Repeat the following procedure 3 times.

- Drive vehicle at a speed of 80 km/h (50 MPH) or more for at least 3 consecutive minutes.

CAUTION: Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.

NOTE: Never turn ignition switch OFF. 3. Check 1st trip DTC.

Is 1st trip DTC detected? YES >> Go to EC-250, "Diagnosis Procedure".

NO >> INSPECTION END

Diagnosis Procedure

1.CHECK GROUND CONNECTION

1. Turn ignition switch OFF.

2. Check ground connection E9. Refer to Ground Inspection in GI-45, "Circuit Inspection".

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

NO >> Repair or replace ground connection.

2.CHECK HO2S3 GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect heated oxygen sensor 3 harness connector.

3. Disconnect ECM harness connector.

4. Check the continuity between HO2S3 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 >> GO TO 3.

3.DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors F58, F101

• Harness for open or short between heated oxygen sensor 3 and ECM

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.CHECK HO2S3 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check the continuity between HO2S3 harness connector and ECM harness connector.

2. Check the continuity between HO2S3 harness connector or ECM harness connector and ground.

3. Also check harness for short to power.

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

NO >> GO TO 5.

5.DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors F58, F101

• Harness for open or short between heated oxygen sensor 3 and ECM

6.CHECK HO2S3 CONNECTOR FOR WATER

Check connectors for water.

Water should not exist.

Is the inspection result normal? YES >> GO TO 7.

NO >> Repair or replace harness or connectors.

7.CHECK HEATED OXYGEN SENSOR 3

Refer to EC-251, "Component Inspection".

Is the inspection result normal? YES >> GO TO 9.

NO >> GO TO 8.

8.REPLACE HEATED OXYGEN SENSOR 3

Replace heated oxygen sensor 3.

CAUTION: • Discard any 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 sensor, clean exhaust system threads using oxygen sensor thread cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant (commercial service tool).

>> INSPECTION END

9.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 3

CAUTION: Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.

1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.

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 the engine and drive vehicle at a speed of 80 km/h (50 MPH) or more for at least 3 consecutive minutes.

NOTE: Keep the vehicle speed as steady as possible during the cruising.

5. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select “HO2S3 (B1)” as the monitor item with CONSULT-III.

6. Check “HO2S3 (B1)” at idle speed when adjusting “FUEL INJECTION” to ±25%.

“HO2S3 (B1)” should be above 0.68V at least once when the “FUEL INJECTION” is +25%.

“HO2S3 (B1)” should be below 0.18V 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 3-I

CAUTION: Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.

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 the engine and drive vehicle at a speed of 80 km/h (50 MPH) or more for at least 3 consecutive minutes.

NOTE: Keep the vehicle speed as steady as possible during the cruising.

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

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 4.

4.CHECK HEATED OXYGEN SENSOR 3-II

1. Keep vehicle at idling for 10 minutes.

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

Is the inspection result normal? YES >> INSPECTION END

NO >> GO TO 5.

5.CHECK HEATED OXYGEN SENSOR 3-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 6.

6.REPLACE HEATED OXYGEN SENSOR 3

Replace heated oxygen sensor 3.

CAUTION: • Discard any 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 sensor, clean exhaust system threads using oxygen sensor thread cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant (commercial service tool).

>> INSPECTION END