Pinpoint Test D: The Four Wheel Drive (4WD) Control Module Does Not Respond To The Diagnostic Tool

WARNING: This page is about a different car, the 2004 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

D1 CHECK THE 4WD CONTROL MODULE C281a FOR DAMAGE
- Key in OFF position.
- Disconnect: 4WD Control Module C281a.
- Inspect the 4WD control module C281a for damage.
- Is the 4WD control module C281a OK?
1. Yes : GO to D2.
2. No : REPAIR the 4WD control module C281a. CARRY OUT the data link diagnostics test.
D2 CHECK CIRCUIT 70 (LB/WH) FOR AN OPEN
- Measure the resistance between the 4WD control module C281a pin 4, circuit 70 (LB/WH), harness side and the DLC C251 pin 7, circuit 70 (LB/WH), harness side.
  
  Fig 1: Checking Circuit 70 (LB/WH) For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
1. Yes : GO to D3.
2. No : REPAIR the circuit. CARRY OUT the data link diagnostics test.
D3 CHECK FOR CORRECT 4WD CONTROL MODULE OPERATION
- Disconnect all the 4WD control module connectors.
- Check for:
  - Corrosion
  - Pushed-out pins
- Connect all the 4WD control module 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 4WD control module. REFER to FOUR WHEEL DRIVE SYSTEMS . CARRY OUT the data link diagnostics test.
2. No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.