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

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Module Communications Network for schematic and connector information.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Lighting Control Module for schematic and connector information.

Normal Operation 

The lighting control module (LCM) communicates with the scan tool through the standard corporate protocol (SCP) communication network. Circuits 914 (TN/OG) (SCP +) and 915 (PK/LB) (SCP-) provide the network connection to the LCM. The LCM shares the SCP network with the driver door module (DDM) (if equipped), the heating ventilation air conditioning (HVAC) module (if equipped) and the overhead console message center (MC) (if equipped). Voltage for the LCM is provided by circuit 221 (OG/WH). Circuit 676 (PK/OG) provides ground.

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• LCM

PINPOINT TEST D: THE LIGHTING CONTROL MODULE (LCM) DOES NOT RESPOND TO THE SCAN TOOL 

1. D1 CHECK THE LCM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN 
   • Key in OFF position.
   • Disconnect: LCM C2145a
   • Key in ON position.
   Fig 1: Checking Circuits For Open
   Courtesy of FORD MOTOR CO.
   • Measure the voltage between the LCM C2145a-13, circuit 221 (OG/WH), harness side and ground.
   • Is the voltage greater than 10 volts? 
   1. YES  : Go to  D2.
   2. NO  : VERIFY the central junction box (CJB) fuse 6 (7.5A) 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
   Fig 2: Checking Circuits For Open
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the LCM C2145a-11, circuit 676 (PK/OG), harness side and ground; and C2145c-7, circuit 676 (PK/OG), harness side and ground.
   • 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 DATA LINK CONNECTOR (DLC) FOR AN OPEN 
   Fig 3: Checking Circuit For Open
   Courtesy of FORD MOTOR CO.
   • 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 4: Checking Circuit For Open
   Courtesy 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.
   • 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.