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Home >> Infiniti >> 2012 >> M37 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS U0101 Through P0153 >> DTC U1003: Can Comm Circuit >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK VVEL CAN COMMUNICATION CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect VVEL control module harness connector.
    4. Check the continuity between ECM harness connector and VVEL control module harness connector.
      ECM VVEL control module Continuity
      Connector Terminal Connector Terminal
      F102 54 E15 24 Existed
      55 11
    5. Also check harness for short to ground and power.

      Is the inspection result normal? 

      YES: GO TO  3.

      NO: GO TO 2.

  2. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connector E20, F40
    • Harness for open or short between ECM and VVEL control module

      : Repair open circuit or short to ground or short to power in harness or connectors.

  3. CHECK INTERMITTENT INCIDENT 

    Refer to "INTERMITTENT INCIDENT ".

    Is the inspection result normal? 

    YES: GO TO 4.

    NO: Repair or replace.

  4. REPLACE VVEL CONTROL MODULE 
    1. Replace VVEL control module.
    2. Go to "WORK PROCEDURE ".

      : GO TO 5.

  5. PERFORM DTC CONFIRMATION PROCEDURE 
    1. Reconnect all harness connectors disconnected.
    2. Turn ignition switch ON.
    3. Erase DTC.
    4. Perform DTC Confirmation Procedure.

      See "DTC LOGIC ".

    5. Check DTC.

      Is the DTC U1003 displayed again? 

      YES: GO TO 6.

      NO: INSPECTION END

  6. REPLACE ECM 
    1. Replace ECM.
    2. Go to "WORK PROCEDURE ".

      : INSPECTION END