Pinpoint Test M : The TCM (Transmission Control Module) Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2018 Ford Fiesta. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.

M1 CHECK THE TCM (TRANSMISSION CONTROL MODULE) VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

Ignition OFF.

Disconnect TCM C1750A.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1750A-1	Courtesy of FORD MOTOR COMPANY	Ground
C1750A-2	Courtesy of FORD MOTOR COMPANY	Ground
C1750A-18	Courtesy of FORD MOTOR COMPANY	Ground
C1750A-31	Courtesy of FORD MOTOR COMPANY	Ground

Are the voltages greater than 11 volts?

Yes

GO to M2

No	VERIFY the BJB fuses 34 (40A), 42 (7.5A) and CJB fuse 23 (7.5A) are OK. If OK, REPAIR the circuit in question. If not OK, REFER to OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short.

M2 CHECK THE TCM (TRANSMISSION CONTROL MODULE) GROUND CIRCUITS FOR AN OPEN

Ignition OFF.

Disconnect negative battery cable.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1750A-3	Courtesy of FORD MOTOR COMPANY	Ground
C1750A-4	Courtesy of FORD MOTOR COMPANY	Ground
C1750A-5	Courtesy of FORD MOTOR COMPANY	Ground
C1750A-6	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms?

Yes

GO to M3

No	REPAIR the circuit in question. CONNECT the negative battery cable.

M3 CHECK THE HS-CAN (HIGH-SPEED CONTROLLER AREA NETWORK) CIRCUITS BETWEEN THE TCM (TRANSMISSION CONTROL MODULE) AND THE DLC (DATA LINK CONNECTOR) FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1750A-34	Courtesy of FORD MOTOR COMPANY	C251-6
C1750A-35	Courtesy of FORD MOTOR COMPANY	C251-14

Are the resistances less than 3 ohms?

Yes	CONNECT the negative battery cable. GO to M4

No	REPAIR the circuit in question. CONNECT the negative battery cable.

M4 CHECK FOR CORRECT TCM (TRANSMISSION CONTROL MODULE) OPERATION

Ignition OFF.

Disconnect and inspect the TCM connectors.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Reconnect the TCM connectors. Make sure they seat and latch correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes	CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new TCM. REFER to: Transmission Control Module (TCM) .

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.