Pinpoint Test A: The Differential Electronic Module (DEM) Does Not Respond To The Diagnostic Tool

WARNING: This page is about a different car, the 2006 Mercury Montego, 2006 Ford Freestyle, and 2006 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.

A1 CHECK THE DEM C3269 FOR DAMAGE
- Key in OFF position.
- Disconnect: DEM C3269.
- Inspect the DEM )3269 for damage.
- Is the DEM C3269 OK?
Yes: GO to A2.

No: REPAIR the DEM C3269 as necessary. CARRY OUT the data link diagnostics test.

A2 CHECK THE HIGH SPEED CAN CIRCUITS BETWEEN THE DLC AND THE DEM FOR AN OPEN
- Measure the resistance between the DEM C3269-8, circuit 1908 (WH), harness side and the DLC C251-6, circuit 1908 (WH), harness side; and between the DEM C3269-7, circuit 1909 (BK), harness side and the DLC C251-14, circuit 1909 (BK), harness side.
  
  Fig 1: Checking High Speed CAN Circuits Between DLC & DEM
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
Yes: GO to A3.

No: REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
A3 CHECK FOR CORRECT DEM OPERATION
- Disconnect all the DEM connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all the DEM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes: INSTALL a new DEM. REFER to INSTALLATION . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

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 self-test. CARRY OUT the data link diagnostics test.