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Nissan Sentra B18 (2020-2025) Service Manual: P0603 Ecm

Dtc Description

DTC Description

DTC DETECTION LOGIC

DTC

CONSULT screen terms

(Trouble diagnosis content)

DTC detection condition

P0603

ECM BACK UP/CIRCUIT

[Internal Control Module Keep Alive Memory (KAM) Error]

Diagnosis condition

Ignition switch ON

Signal (terminal)

—

Threshold

ECM back up system does not function properly

Diagnosis delay time

—

POSSIBLE CAUSE

  • Harness or connectors (ECM power supply circuit is open or shorted.)

  • ECM

FAIL-SAFE

Engine Control System

Engine operating condition in fail-safe mode

Fail safe mode

Nissan Sentra Vehicle behavior

Traveling control mode

Accelerator angle variation control

ECM controls the accelerator pedal depression speed to make it slower than actual speed. This causes a drop in accelerating performance and encourages the driver to repair malfunction.

Note:

ECM does not control the accelerator pedal releasing speed.

Engine output control 1

ECM reduces the engine output, according to the rise in engine speed. This reduces the Nissan Sentra vehicle speed to encourage the driver to repair malfunction.

Driving at 70 km/h (44 MPH) or more is possible.

Note:

This value is a reference value converted from engine power to Nissan Sentra vehicle speed. Actual power limitation value differs due to the malfunctioning part and driving condition.

Idle Start/Stop System

When a DTC is detected, the start/stop indicator lamp blinks slowly and the idle start/stop system operation is prohibited.

When ECM detects error while operating the idle start/stop system, ECM restarts the engine.

Confirmation Procedure

Confirmation Procedure

  1. 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 between 11 V or more with ignition switch.

    >>

    GO TO 2.

  2. PERFORM DTC CONFIRMATION PROCEDURE

    1. Turn ignition switch ON and wait at least 1 second.

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

    3. Repeat step 1 and 2 for 10 times.

    4. Turn ignition switch ON.

    5. Check 1st trip DTC.

    Is 1st trip DTC detected?

    YES >>

    Proceed to DTC Diagnosis Procedure.

    NO >>

    .INSPECTION END

Dtc Diagnosis Procedure

DTC Diagnosis Procedure

  1. INSPECTION START

    Check that the battery negative terminal is not disconnected during ignition switch ON.

    Is the inspection result normal?

    YES >>

    GO TO 3.

    NO >>

    GO TO 2.

  2. ERASE DTC

    1. Start the engine and let it idle at least 10 seconds.

    2. Turn ignition switch OFF.

    3. Repeat steps 1 and 2 for 4 times.

    4. Erase DTC.

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

    6. Start the engine and let it idle for 10 seconds.

    7. Check 1st trip DTC.

    Is DTC P062F detected again?

    YES >>

    Replace ECM. Refer to ECM : Removal & Installation.

    NO >>

    INSPECTION END

  3. CHECK ECM POWER SUPPLY AND GROUND CIRCUIT

    Perform trouble diagnosis for ECM power supply, ground, Battery terminal tightness, Fuse, EGI relay and connector pin pressure. Refer to Diagnosis Procedure.

    Is the inspection result normal?

    YES >>

    GO TO 4.

    NO >>

    Repair or replace error-detected parts.

  4. CHECK INTERMITTENT INCIDENT

    Check intermittent incident. Refer to Intermittent Incident.

    Is the inspection result normal?

    YES >>

    GO TO 5.

    NO >>

    Repair or replace error-detected parts.

  5. PERFORM DTC CONFIRMATION PROCEDURE

    1. Turn ignition switch ON.

    2. Erase DTC.

    3. Perform DTC confirmation procedure. Refer to DTC Description.

    Is the DTC P0603 or P062F detected again?

    YES >>

    Replace ECM. Refer to ECM : Removal & Installation.

    NO >>

    INSPECTION END

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