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Nissan Sentra B18 (2020-2025) Service Manual: P050a Cold Start Control

Dtc Description

DTC 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

DTC

CONSULT screen terms

(Trouble diagnosis content)

DTC detection condition

P050A

COLD START CONTROL

(Cold start idle air control system performance)

Diagnosis condition

—

Signal (terminal)

—

Threshold

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

Diagnosis delay time

—

POSSIBLE CAUSE

  • Lack of intake air volume

  • Fuel injection system

  • ECM

FAIL-SAFE

Not applicable

Confirmation Procedure

Confirmation Procedure

  1. CHECK DTC PRIORITY

    If DTC P050A, P050B or P050E is displayed with other DTC, first perform the trouble diagnosis for other DTC.

    Is applicable DTC detected?

    YES >>

    Perform diagnosis of applicable. Refer to DTC Index.

    NO >>

    GO TO 2.

  2. 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 11 V at idle.

    >>

    GO TO 3.

  3. PERFORM DTC CONFIRMATION PROCEDURE-1

    With CONSULT

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

    2. Turn ignition switch ON.

    3. Select “DATA MONITOR” mode of “ENGINE” using 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 15°C (59°F) and 36°C (97°F)?

    YES >>

    GO TO 4.

    NO-1 [If it is below 15°C (59°F)] >>

    Warm up the engine until the value of “COOLANT TEMP/S” reaches 15°C (59°F) or more. Retry from step 1.

    NO-2 [If it is above 36°C (97°F)] >>

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

  4. PERFORM DTC CONFIRMATION PROCEDURE-2

    With CONSULT

    1. Shift the select lever to N position.

    2. Start the engine and warm up in idle with the value of “COOLANT TEMP/S” between 15°C (59°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?

    YES >>

    Proceed to DTC Diagnosis Procedure.

    NO-1 >>

    To check malfunction symptom before repair: Refer to Intermittent Incident.

    NO-2 >>

    Confirmation after repair: INSPECTION END

Dtc Diagnosis Procedure

DTC Diagnosis Procedure

  1. CHECK DTC PRIORITY

    If DTC P050A, P050B or P050E is displayed with other DTC, first perform the trouble diagnosis for other DTC.

    Is applicable DTC detected?

    YES >>

    Perform diagnosis of applicable. Refer to DTC Index.

    NO >>

    GO TO 2.

  2. PERFORM IDLE AIR VOLUME LEARNING

    Perform Idle Air Volume Learning. Refer to Work Procedure.

    Is Idle Air Volume Learning carried out successfully?

    YES >>

    GO TO 3.

    NO >>

    Follow the instruction of Idle Air Volume Learning.

  3. 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?

    YES >>

    GO TO 4.

    NO >>

    Repair or replace malfunctioning part

  4. CHECK FUEL INJECTION SYSTEM FUNCTION

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

    Is the inspection result normal?

    YES >>

    GO TO 5.

    NO >>

    Refer to DTC Diagnosis Procedure. for DTC P0171.

  5. PERFORM DTC CONFIRMATION PROCEDURE

    1. Turn ignition switch ON.

    2. Erase DTC.

    3. Perform DTC Confirmation Procedure. Refer to DTC Description.

    Is the 1st trip DTC P050A, P050B or P050E displayed again?

    YES >>

    Replace ECM. Refer to ECM : Removal & Installation.

    NO >>

    INSPECTION END

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