Nissan Altima 2007-2012 Service Manual: P1421 Cold start control

Description

ECM controls ignition timing and engine idle speed when engine is started with prewarming up condition.

This control promotes the activation of three way catalyst by heating the catalyst and reduces emissions.

DTC Logic

DTC DETECTION LOGIC

NOTE: If DTC P1421 is displayed with other DTC, first perform the trouble diagnosis for other DTC.

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.

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

>> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDURE

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

2. Turn ignition switch ON.

3. Select “DATA MONITOR” mode with CONSULT-III.

4. Check that the “COOLAN TEMP/S” indication is between 4°C (39°F) and 36°C (97°F).

If “COOLAN TEMP/S” indication is within the specified value, go to the following step.

If “COOLAN TEMP/S” indication is out of the specified value, cool engine down or warm engine up and go to step 1.

5. Start engine and let it idle for 5 minutes.

6. Check 1st trip DTC.

Follow the procedure “With CONSULT-III” above.

Is 1st trip DTC detected? YES >> Go to EC-377, "Diagnosis Procedure".

NO >> INSPECTION END

Diagnosis Procedure

1.PERFORM IDLE AIR VOLUME LEARNING

Perform EC-30, "IDLE AIR VOLUME LEARNING : Special Repair Requirement".

Is Idle Air Volume Learning carried out successfully? YES >> GO TO 2.

NO >> Follow the instruction of Idle Air Volume Learning.

2.CHECK INTAKE SYSTEM

Check for the cause of intake air volume lacking. Refer to the following.

• Crushed intake air passage

• Intake air passage clogging

Is the inspection result normal? YES >> GO TO 3.

NO >> Repair or replace malfunctioning part

3.CHECK FUEL INJECTION SYSTEM FUNCTION

Perform DTC CONFIRMATION PROCEDURE for DTC P0171. Refer to EC-254, "DTC Logic".

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

NO >> Go to EC-255, "Diagnosis Procedure" for DTC P0171.

4.PERFORM DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Select “SELF DIAG RESULTS” mode with CONSULT-III.

3. Touch “ERASE”.

4. Perform DTC CONFIRMATION PROCEDURE.

See EC-377, "DTC Logic".

1. Turn ignition switch ON.

2. Select Service $04 with GST.

3. Perform DTC CONFIRMATION PROCEDURE.

See EC-377, "DTC Logic".

Is the 1st trip DTC P1421 displayed again? YES >> GO TO 5.

NO >> INSPECTION END

5.REPLACE ECM

1. Replace ECM.

2. Go to EC-27, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair Requirement".

>> INSPECTION END

    P1226 TP Sensor
    Description Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc. The throttle position sensor responds to the throttle valve movement. The throt ...

    P1550 battery current sensor
    Description The power generation voltage variable control enables fuel consumption to be decreased by reducing the engine load which is caused by the power generation of the generator. The batt ...

    Other materials:

    Forward-facing child restraint installation using the seat belts
    WARNING The three-point seat belt with Automatic Locking Retractor (ALR) must be used when installing a child restraint. Failure to use the ALR mode will result in the child restraint not being properly secured. The restraint could tip over or be loose and cause injury to a child in a sudden ...

    Bluetooth® Hands-Free Phone System with Navigation System (if so equipped)
    WARNING ● Use a phone after stopping your vehicle in a safe location. If you have to use a phone while driving, exercise extreme caution at all times so full attention may be given to vehicle operation. ● If you are unable to devote full attention to vehicle operation while talkin ...

    Driver side
    Description Detects condition of the front power window motor LH operation and transmits to main power window and door lock/unlock switch as pulse signal. Component Function Check 1. CHECK ENCODER OPERATION Does front door glass LH perform AUTO open/close operation normally when operating ...