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

WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK THE DEM C3269 FOR DAMAGE
- Key in OFF position.
- Disconnect: DEM C3269.
- Inspect the DEM C3269 for damage.
- Is the DEM C3269 OK?
- Yes : GO to A2.
- No : REPAIR the DEM C3269 as necessary. CARRY OUT the PINPOINT TEST PC: DATA LINK DIAGNOSTICS TEST .
A2 CHECK HIGH SPEED CONTROLLER AREA NETWORK (CAN) CIRCUITS 1908 (WH) AND 1909 (BK) BETWEEN THE DATA LINK CONNECTOR (DLC) C251 AND THE DEM C3269 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: Measuring High Speed Controller Area Network (CAN) Circuits 1908 (WH) And 1909 (BK) Between Data Link Connector (DLC) C251 And DEM C3269
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : GO to A3.
- No : REPAIR the circuit. CLEAR the diagnostic trouble codes (DTCs). REPEAT the self-test. CARRY OUT the PINPOINT TEST PC: 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 REAR DRIVE AXLE/DIFFERENTIAL . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the PINPOINT TEST PC: 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 PINPOINT TEST PC: DATA LINK DIAGNOSTICS TEST .