Nissan Altima (L32) 2007-2012 Service Manual: P2A00, P2A03 A/F sensor 1

Description

The air fuel ratio (A/F) sensor 1 is a planar one-cell limit current sensor.

The sensor element of the A/F sensor 1 is composed an electrode layer, which transports ions. It has a heater in the element.

The sensor is capable of precise measurement = 1, but also in the lean and rich range. Together with its control electronics, the sensor outputs a clear, continuous signal throughout a wide range.

The exhaust gas components diffuse via the diffusion layer at the sensor cell. An electrode layer is applied voltage, and this current relative oxygen density in lean. Also this current relative hydrocarbon density in rich.

Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this electrode layer of current. In addition, a heater is integrated in the sensor to ensure the required operating temperature of approximately 800°C (1,472°F).

DTC Logic

DTC DETECTION LOGIC

To judge the malfunction, the A/F signal computed by ECM from the A/F sensor 1 signal is monitored so it will not shift to LEAN side or RICH side.

DTC CONFIRMATION PROCEDURE

1.PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next test.

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

2. Turn ignition switch ON.

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

TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

>> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDURE

1. Clear the mixture ratio self-learning value. Refer to EC-1055, "MIXTURE RATIO SELF-LEARNING VALUE CLEAR : Special Repair Requirement".

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

3. Turn ignition switch ON.

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 1 minute under no load.

6. Let engine idle for 1 minute.

7. Keep engine speed between 2,500 and 3,000 rpm for 20 minutes.

8. Check 1st trip DTC.

Is 1st trip DTC detected? YES >> Go to EC-1464, "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.RETIGHTEN A/F SENSOR 1

Loosen and retighten the A/F sensor 1. Refer to EM-136, "Removal and Installation".

>> GO TO 3.

3.CHECK HARNESS CONNECTOR

1. Turn ignition switch OFF.

2. Disconnect A/F sensor 1 harness connector.

3. Check that water is not inside connectors.

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

NO >> Repair or replace harness connector.

4.CHECK FOR INTAKE AIR LEAKAGE

1. Start engine and run it at idle.

2. Listen for an intake air leakage after the mass air flow sensor.

Is intake air leakage detected? YES >> GO TO 5.

NO >> Repair or replace malfunctioning part.

5.CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE

1. Clear the mixture ratio self-learning value. Refer to EC-1055, "MIXTURE RATIO SELF-LEARNING VALUE CLEAR : Special Repair Requirement".

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

Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected? Is it difficult to start engine? YES >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-1266, "DTC Logic" or EC-1270, "DTC Logic".

NO >> GO TO 6.

6.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

1. Disconnect A/F sensor 1 harness connector.

2. Turn ignition switch ON.

3. Check the voltage between A/F sensor 1 harness connector and ground.

Is the inspection result normal? YES >> GO TO 8.

NO >> GO TO 7.

7.DETECT MALFUNCTIONING PART

Check the following.

• IPDM E/R harness connector F10

• 15 A fuse (No. 37) • Harness for open or short between A/F sensor 1 and IPDM E/R

>> Repair or replace harness or connectors.

8.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

5. Also check harness for short to power.

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

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

9.CHECK INTERMITTENT INCIDENT

Perform GI-42, "Intermittent Incident".

Is the inspection result normal? YES >> GO TO 10.

NO >> Repair or replace malfunctioning part.

10.REPLACE AIR FUEL RATIO (A/F) SENSOR 1

Replace malfunctioning air fuel ratio (A/F) sensor 1. CAUTION: • Discard any A/F 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.

>> INSPECTION END