Pinpoint Test I: The HCM Does Not Respond To The Scan Tool

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. 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 will result in false resistance readings. Refer to BATTERY, MOUNTING AND CABLES .

I1 CHECK THE HCM VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: HCM C1600.
- Ignition ON.
- Measure the voltage between the HCM C1600-10, circuit CBP42 (GN), harness side and ground.
  
  Fig 1: Checking HCM Voltage Supply Circuit For An Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to I2.
- No : VERIFY the Smart Junction Box (SJB) fuse 42 (10A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the short circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.
I2 CHECK THE HCM GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the HCM C1600-3, circuit GD121 (BK/YE), harness side and ground.
  
  Fig 2: Checking HCM Ground Circuit For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to I3.
- No : REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
I3 CHECK THE HS-CAN CIRCUITS BETWEEN THE HCM AND THE DLC FOR AN OPEN
- Measure the resistance between the HCM C1600-14, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
  
  Fig 3: Checking HS-CAN Circuits Between HCM And DLC For An Open (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the HCM C1600-13, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
  
  Fig 4: Checking HS-CAN Circuits Between HCM And DLC For An Open (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : CONNECT the negative battery cable. GO to I4.
- No : REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
I4 CHECK FOR CORRECT HCM OPERATION

Disconnect the HCM connector.
Check for:
- corrosion
- damaged pins
- pushed-out pins
Connect the HCM connector and make sure it seats correctly.
Verify the concern is still present.
Is the concern still present?

Yes : INSTALL a new HCM. REFER to EXTERIOR LIGHTING . CLEAR the DTCs. REPEAT the network test with the scan tool.
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.