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Home >> Infiniti >> 2018 >> QX30 Essential, FWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter, Warning Lamp Indicator (DTC/Circuit Diagnosis) >> DTC/Circuit Diagnosis >> DTC P2556 Coolant Level Switch >> Diagnosis Procedure >> P2556-7B

Diagnosis Procedure: P2556-7B

  1. CHECK POWER SUPPLY VOLTAGE OF BCM 

    Check power supply and ground circuit of BCM. Refer to Diagnosis Procedure .

    Is the inspection result normal?

    YES

    GO TO 2.

    NO

    Repair or replace the malfunctioning parts

  2. CHECK ENGINE COOLANT LEVEL 
    1. Turn the ignition switch OFF.
    2. Check the engine coolant level. Refer to Inspection .

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Refill the engine coolant, and GO TO 3.

  3. PERFORM DTC CONFIRMATION PROCEDURE AGAIN 

    Perform DTC confirmation procedure again. Refer to DTC Description 

    Is DTC P2556 detected again?

    YES

    GO TO 4.

    NO

    INSPECTION END

  4. CHECK COOLANT LEVEL SWITCH 
    1. Turn the ignition switch OFF.
    2. Disconnect the coolant level switch harness connector.
    3. Insert jumper on the coolant level switch harness connector.

      Coolant level switch

      Specified value

      Terminal

      1

      4

      OK

    4. Remove jumper on the coolant level switch harness connector.

      Coolant level switch

      Specified value

      Terminal

      1

      4

      Not OK

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Replace reservoir tank. Refer to Removal and Installation .

  5. CHECK COOLANT LEVEL SWITCH CIRCUIT 
    1. Turn the ignition switch OFF.
    2. Disconnect the BCM harness connector.
    3. Check the continuity between coolant level switch harness connector and BCM harness connector.

      Coolant level switch

      BCM

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      E25

      1

      E16

      159

      Existed

      4

      158

      Existed

    4. Check the continuity between coolant level switch harness connector and ground.

      Coolant level switch

      --

      Continuity

      Connector

      Terminal

      E25

      4

      Ground

      Not existed

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Repair harness or connector.

  6. CHECK COOLANT LEVEL SWITCH 
    1. Drain engine coolant from reservoir tank.
    2. Check the continuity between coolant level switch connector.

      Coolant level switch

      Continuity

      Terminal

      1

      4

      Not existed

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Replace reservoir tank. Refer to Removal and Installation .