Pinpoint Test G: The TCM 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 .

G1 CHECK THE TCM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

Ignition OFF.
Disconnect: TCM C1458a (2.5L Hybrid).
Disconnect: TCM C1533 (3.5L).
Ignition ON.
For 3.5L, measure the voltage between the TCM C1533-1, circuit SBB16 (VT/RD), harness side and ground; and between the TCM C1533-11, circuit CBP44 (VT), harness side and ground.

Fig 1: Checking TCM Voltage Supply Circuits For An Open
Courtesy of FORD MOTOR CO.

For 2.5L hybrid, measure the voltage between the TCM , harness side and ground as follows:

VOLTAGE REFERENCE TABLE

Connector-Pin	Circuit
C1458a-4	CBB39 (VT/WH)
C1458a-5	CBB39 (VT/WH)
C1458a-12	SBB23 (RD)

Fig 2: Measuring Voltage Between TCM Circuit And Ground

Courtesy of FORD MOTOR CO.

Are the voltages greater than 10 volts?

Yes : GO to G2.
No : For 3.5L gasoline, VERIFY the Battery Junction Box (BJB) fuse 16 (15A) or Smart Junction Box (SJB) fuse 44 (10A) is OK. For 2.5L hybrid, VERIFY the BJB fuse 23 (10A) or fuse 39 (10A) is OK. If OK, REPAIR the circuit in question. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool.

G2 CHECK THE TCM GROUND CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- For 3.5L gasoline, measure the resistance between the TCM C1533-9, circuit GD120 (BK/GN), harness side and ground.
  
  Fig 3: Measuring Resistance Between TCM C1533-9, Circuit GD120 (BK/GN), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- For 2.5L hybrid measure the resistance between the TCM C1458a-2, circuit GD121 (BK/YE), harness side and ground; and between the TCM C1458a-8, circuit GD121 (BK/YE), harness side and ground.
  
  Fig 4: Checking TCM Ground Circuits For An Open
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : For 3.5L engine, GO to G3.
  For 2.5L hybrid engine, GO to G4.
- No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
G3 CHECK THE HS-CAN CIRCUITS BETWEEN THE TCM AND THE DLC FOR AN OPEN - 3.5L ENGINE
- Measure the resistance between the TCM C1533-14, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
  
  Fig 5: Checking HS-CAN Circuits Between TCM And DLC For An Open - 3.5L Engine (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the TCM C1533-6, circuit
  VDB05 (WH), harness side and the DLC C251-14, circuit
  
  VDB05 (WH), harness side.
  
  Fig 6: Checking HS-CAN Circuits Between TCM And DLC For An Open - 3.5L Engine (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : CONNECT the negative battery cable. GO to G5.
- No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
G4 CHECK THE HS-CAN CIRCUITS BETWEEN THE TCM AND THE DLC FOR AN OPEN - 2.5L HYBRID ENGINE
- Measure the resistance between the TCM C1458a-1, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
  
  Fig 7: Checking HS-CAN Circuits Between TCM And DLC For An Open - 2.5L Hybrid Engine (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the TCM C1458a-7, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
  
  Fig 8: Checking HS-CAN Circuits Between TCM And DLC For An Open - 2.5L Hybrid Engine (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : CONNECT the negative battery cable. GO to G5.
- No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
G5 CHECK FOR CORRECT TCM OPERATION

Disconnect all the TCM connectors.
Check for:
- corrosion
- damaged pins
- pushed-out pins
Connect all the TCM 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 TCM. REFER to IN-VEHICLE REPAIR . 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.