Pinpoint Test D: The 4X4 Control Module 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, All Wheel Drive (AWD) for schematic and connector information.

Normal Operation 

The 4X4 control module communicates with the scan tool through the high speed controller area network (HS-CAN). Circuits VDB04 (WH/BU) (HS-CAN +) and VDB05 (WH) (HS-CAN -) provide the network connection to the 4X4 control module. The 4X4 control module shares the HS-CAN with the PCM, the accessory protocol interface module (APIM), the ABS module, the occupant classification system module (OCSM), the restraints control module (RCM), the headlamp control module (HCM) (if equipped), the steering angle sensor module (SASM) (if equipped) and the instrument cluster (IC). Voltage is supplied by circuits CBP35 (YE/GY) and SBP11 (BU/RD). Ground is supplied by circuit GD140 (BK/GN).

This pinpoint test is intended to diagnose the following:

• Fuse
• Wiring, terminals or connectors
• 4X4 control module

PINPOINT TEST D: THE 4X4 CONTROL MODULE DOES NOT RESPOND TO THE SCAN TOOL 

1. D1 CHECK THE 4X4 CONTROL MODULE VOLTAGE SUPPLY CIRCUITS FOR AN OPEN 
   • Key in OFF position.
   • Disconnect: 4X4 Control Module C281
   • Key in ON position.
   Fig 1: Checking Circuit For Voltage
   Courtesy of FORD MOTOR CO.
   • Measure the voltage between the 4X4 control module C281-5, circuit CBP35 (YE/GY), harness side and ground; and between the 4X4 control module C281-6, circuit SBP11 (BU/RD), harness side and ground.
   • Are the voltages greater than 10 volts? 
   1. YES  : Go to  D2.
   2. NO  : VERIFY the smart junction box (SJB) fuse 11 (10A) or fuse 35 (10A) is OK. If OK, REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
2. D2 CHECK THE 4X4 CONTROL MODULE GROUND CIRCUIT FOR AN OPEN 
   • Key in OFF position.
   Fig 2: Checking Circuit For Open
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the 4X4 control module C280-15, circuit GD140 (BK/GN), harness side and ground.
   • Is the resistance less than 5 ohms? 
   1. YES  : Go to  D3.
   2. NO  : REPAIR the circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.
3. D3 CHECK THE HS-CAN CIRCUITS BETWEEN THE 4X4 CONTROL MODULE AND THE DATA LINK CONNECTOR (DLC) FOR AN OPEN 
   Fig 3: Measuring Resistance Between 4WD Control Module C281-4, Circuit VDB04 (WH/BU) & DLC C251-6
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the 4X4 control module C281-4, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
   Fig 4: Measuring Resistance Between 4WD Control Module C281-12, Circuit VDB05 (WH) & DLC C251-14
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between the 4X4 control module C281-12, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), 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 4X4 CONTROL MODULE OPERATION 
   • Disconnect the 4X4 control module connector.
   • Check for:
     • corrosion
     • damaged pins
     • pushed-out pins
   • Connect the 4X4 control module connector and make sure it seats correctly.
   • Operate the system and verify the concern is still present.
   • Is the concern still present? 
   1. YES  : INSTALL a new 4X4 control module. REFER to FOUR WHEEL DRIVE (4WD) SYSTEMS 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.