Nissan Murano: Dtc/circuit Diagnosis / P050a Cold Start Control

DTC Description

DESCRIPTION

ECM controls ignition timing and engine idle speed when engine is started with pre-warming up condition.

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

DTC DETECTION LOGIC

• ECM does not control engine idle speed properly when engine is started with pre-warming up condition.

• The temperature of the catalyst inlet does not rise to the proper temperature when the engine is started with pre-warming up condition.

POSSIBLE CAUSE

P050A

• Lack of intake air volume

• Fuel injection system

• ECM

P050B

• Lack of intake air volume

• Fuel injection system

• ECM

FAIL-SAFE

Not applicable

CHECK DTC PRIORITY

If DTC P050A, P050E is displayed with other DTC, first perform the trouble diagnosis for the other DTC.

Is applicable DTC detected?

Perform diagnosis of applicable. Refer to DTC Index.

GO TO 2.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure 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 3.

PERFORM DTC CONFIRMATION PROCEDURE-I

With CONSULT

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

2. Turn ignition switch ON.

3. Select “DATA MONITOR” mode with CONSULT.

4. Check the indication of “COOLANT TEMP/S”.

With GST

Follow the procedure “With CONSULT” above.

Is the value of “COOLANT TEMP/S” between 4°C (39°F) and 36°C (97°F)?

GO TO 4.

Warm up the engine until the value of “COOLANT TEMP/S” reaches 4°C (39°F) or more. Retry from step 1.

Cool engine down to less than 36°C (97°F). Retry from step 1.

PERFORM DTC CONFIRMATION PROCEDURE-II

With CONSULT

1. Set the select lever in N range.

2. Start the engine and warm up in idle with the value of “COOLANT TEMP/S” between 4°C (39°F) and 40°C (104°F) for more than 15 seconds.

3. Check 1st trip DTC.

With GST

Follow the procedure “With CONSULT” above.

Is 1st trip DTC detected?

Proceed to Diagnosis Procedure.

INSPECTION END

CHECK DTC PRIORITY

If DTC P050A, P050E is displayed with other DTC, first perform the trouble diagnosis for the other DTC.

Is applicable DTC detected?

Perform diagnosis of applicable. Refer to DTC Index.

GO TO 2.

PERFORM IDLE AIR VOLUME LEARNING

Perform Description.

Is Idle Air Volume Learning carried out successfully?

GO TO 3.

Follow the instruction of Idle Air Volume Learning.

CHECK Intake system

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

• Crushed intake air passage

• Intake air passage clogging

• Clogging of throttle body

Is the inspection result normal?

GO TO 4.

Repair or replace malfunctioning part

CHECK FUEL INJECTION SYSTEM FUNCTION

Perform DTC Confirmation Procedure for DTC P0171, P0174. Refer to DTC Description.

Is the inspection result normal?

GO TO 5.

Proceed to Diagnosis Procedure for DTC P0171, P0174.

PERFORM DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON.

2. Erase DTC.

3. Perform DTC Confirmation Procedure.

   See DTC Description.

Is the 1st trip DTC P050A, P050E displayed again?

Replace ECM. Refer to Removal and Installation.

INSPECTION END