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Pinpoint Test D: The Lighting Control Module (LCM) Does Not Respond To The Scan Tool

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
  1. D1 CHECK THE LCM VOLTAGE SUPPLY CIRCUIT FOR AN OPEN 
    • Key in OFF position.
    • Disconnect the scan tool cable from the data link connector (DLC).
    • Disconnect: LCM C2145a
    • Key in ON position.
    • Measure the voltage between LCM C2145a-13, circuit 221 (OG/WH), harness side and ground.
      • Fig 1: Checking Circuits For Open
      GF0014636Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  D2.
    2. NO  : VERIFY the central junction box (CJB) fuse 23 (10A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.
  2. D2 CHECK THE LCM GROUND CIRCUITS FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: LCM C2145c
    • Measure the resistance between LCM C2145a-11, circuit 676 (PK/OG), harness side and ground; and C2145c-7, circuit 676 (PK/OG), harness side and ground.
      • Fig 2: Checking Circuits For Open
      GF0014637Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 
    1. YES  : Go to  D3.
    2. NO  : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
  3. D3 CHECK THE SCP CIRCUITS BETWEEN THE LCM AND THE DLC FOR AN OPEN 
    • Measure the resistance between the LCM C2145a-8, circuit 914 (TN/OG), harness side and the DLC C251-2, circuit 914 (TN/OG), harness side.
      • Fig 3: Checking Circuit For Open
      GF0014638Courtesy of FORD MOTOR CO.
    • Measure the resistance between the LCM C2145a-16, circuit 915 (PK/LB), harness side and the DLC C251-10, circuit 915 (PK/LB) harness side.
      • Fig 4: Checking Circuit For Open
      GF0014639Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 
    1. YES  : Go to  D4.
    2. NO  : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
  4. D4 CHECK FOR CORRECT LCM OPERATION 
    • Disconnect all the LCM connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the LCM connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new LCM. REFER to MULTIFUNCTION ELECTRONIC MODULES article. CLEAR the DTCs. REPEAT the network test with the scan tool.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the network test with the scan tool.
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