Pinpoint Test O: The DSM Does Not Respond To The Scan Tool

WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

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

NOTE: Failure to disconnect the battery when instructed results in false resistance readings. Refer to BATTERY, MOUNTING AND CABLES .

O1 CHECK THE DSM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: DSM C3299A .
- Disconnect: DSM C3299B .
- Measure the voltage between the DSM C3299A-1 , circuit SBB23 (WH/RD), harness side and ground.
  
  Fig 1: Measuring Voltage Between DSM C3299A-1, Circuit SBB32 (WH/RD), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Measure the voltage between the DSM C3299B-1 , circuit SBP07 (WH/RD), harness side and ground.
  
  Fig 2: Measuring Voltage Between DDM C3299B-1, Circuit SBP07 (WH/RD), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
  
  Are the voltages greater than 10 volts?
  1. Yes : GO to O2.
  2. No : VERIFY the Battery Junction Box (BJB) fuse 23 (30A) and the Body Control Module (BCM) fuse 7 (7.5) is OK. If OK, REPAIR the circuit in question. If not OK, REFER to the SYSTEM WIRING DIAGRAMS to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool.
O2 CHECK THE DSM GROUND CIRCUIT FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the DSM C3299A-2 , circuit GD145 (BK/BU), harness side and ground.
Fig 3: Measuring Resistance Between DSM C3299A-2, Circuit GD145 (BK/BU), Harness Side And Ground
Courtesy of FORD MOTOR CO.
- Measure the resistance between the DSM C3299B-24 , circuit GD133 (BK), harness side and ground.
  
  Fig 4: Measuring Resistance Between DSM C3299B-24, Circuit GD133 (BK), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
  
  Are the resistances less than 5 ohms?
  1. Yes : GO to O3.
  2. No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
O3 CHECK THE MS-CAN CIRCUITS BETWEEN THE DSM AND THE DLC FOR AN OPEN
- Disconnect: DSM C3299D .
- Measure the resistance between the DSM C3299D-10 , circuit VDB06 (GY/OG), harness side and the DLC C251-3 , circuit VDB06 (GY/OG), harness side.
  
  Fig 5: Measuring Resistance Between DSM C3299D-10 And DLC C251-3, Circuit VDB06 (GY/OG), Harness Side
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the DSM C3299D-9 , circuit VDB07 (VT/OG), harness side and the DLC C251-11 , circuit VDB07 (VT/OG), harness side.
  
  Fig 6: Measuring Resistance Between DSM C3299D-9 And DLC C251-11, Circuit VDB07 (VT/OG), Harness Side
  Courtesy of FORD MOTOR CO.
  
  Are the resistances less than 5 ohms?
  1. Yes : CONNECT the negative battery cable. GO to O4.
  2. No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
O4 CHECK FOR CORRECT DSM OPERATION
- Disconnect all the DSM connectors.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect all the DSM connectors and make sure they are seated correctly.
- Operate the system and verify the concern is still present.
  Is the concern still present?
  1. Yes : INSTALL a new DSM . REFER to SEATING . 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.