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Pinpoint Test A: No Communication With The DEM

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 Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.
  1. A1 CHECK SMART JUNCTION BOX (SJB) MINI-FUSE 19 (10A) 
    • Check SJB mini-fuse 19 (10A).
    • Is the fuse okay? 

    Yes  : GO to  A2.

    No  : INSTALL a new fuse. CHECK the system for normal operation.

  2. A2 CHECK FOR CORRECT DEM OPERATION 
    • Check for loose or not fully seated connection at DEM C3269 and jumper harness C314.
    • Disconnect DEM circuit connectors C3269 and C314:
    • Check for:
      • damaged, bent or pushed-out pins.
      • loose, broken or damaged wires around or leading into the connectors.
      • check the harness jumper wires for damage.
    • Connect DEM C3269 and jumper harness C314; make sure they are fully seated.
      Fig 1: Connecting DEM C3269 & Jumper Harness C314
      G04655352Courtesy of FORD MOTOR CO.
    • Operate the vehicle and verify if the concern is still present.
    • Is the concern still present? 

    Yes:  GO to  A3.

    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.

  3. A3 CHECK CIRCUIT 972 (BK/WH) FOR VOLTAGE 
    • Disconnect: DEM C3269-1.
    • Key in ON position.
    • Measure the voltage between DEM C3269-1, circuit 972 (BK/WH) harness side and ground.
      Fig 2: Measuring Voltage Between DEM C3269-1, Circuit 972 (BK/WH) Harness Side & Ground
      G04655353Courtesy of FORD MOTOR CO.
    • Is the voltage between 9 and 18 volts? 

    Yes:  GO to  A4.

    No:  REPAIR the circuits as necessary. TEST the system for normal operation.

  4. A4 CHECK CIRCUIT 570 (BK) FOR AN OPEN 
    • Key in OFF position.
    • Measure the resistance between DEM C3269-2, circuit 570 (BK) harness side and ground.
      Fig 3: Measuring Resistance Between DEM C3269-2, Circuit 570 (BK) Harness Side & Ground
      G04655354Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 

    Yes:  GO to  A5.

    No:  REPAIR the circuit. TEST the system for normal operation.

  5. A5 CHECK THE HIGH SPEED CAN CIRCUITS BETWEEN THE DLC AND THE DEM FOR AN OPEN 
    • Key in OFF position.
    • Measure the resistance between DEM C3269-8, circuit 1908 (WH), harness side and DLC C251-6, circuit 1908 (WH), harness side; and between DEM C3269-7, circuit 1909 (BK), harness side and DLC C251-14, circuit 1909 (BK), harness side.
      Fig 4: Measuring Resistance Between DEM C3269-8, Circuit 1908 (WH), Harness Side & DLC C251-6, Circuit 1908 (WH), Harness Side; And Between DEM C3269-7, Circuit 1909 (BK), Harness Side & DLC C251-14, Circuit 1909 (BK) & Harness Side
      G04655355Courtesy of FORD MOTOR CO.
    • Are the resistances less than 5 ohms? 

    Yes:  GO to  A6.

    No:  REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

  6. A6 CHECK THE HIGH SPEED CAN CIRCUITS FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Measure the resistance between DEM C3269-8, circuit 1908 (WH), harness side and ground; and between DEM C3269-7, circuit 1909 (BK), harness side and ground.
      Fig 5: Measuring Resistance Between DEM C3269-8, Circuit 1908 (WH), Harness Side & Ground; And Between DEM C3269-7, Circuit 1909 (BK), Harness Side & Ground
      G04655356Courtesy of FORD MOTOR CO.
    • Are the resistances greater than 10,000 ohms? 

    Yes  : GO to  A7.

    No  : REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

  7. A7 CHECK THE RESISTANCE BETWEEN HIGH SPEED CAN CIRCUITS 
    • Key in OFF position.
      • NOTE: The powertrain control module (PCM) and the instrument cluster (IC) must be connected and operating correctly to obtain the correct resistance between the high speed controller area network (HS-CAN) circuits.
      Fig 6: Measuring Resistance Between DEM C3269-8 Circuit 1908 (WH) Harness Side & DEM C3269-7 Circuit 1909 (BK) Harness Side
      G04655357Courtesy of FORD MOTOR CO.
    • Measure the resistance between DEM C3269-8 circuit 1908 (WH) harness side and DEM C3269-7 circuit 1909 (BK) harness side.
    • Is the resistance 60 ohm (± 5 ohms)? 

    Yes:  INSTALL a new DEM. REFER to INSTALLATION . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

    No:  REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

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