Pinpoint Test L: The TELEMATIC Control Unit (TCU) Module Does Not Respond To The Diagnostic Scan Tool

Refer to Module Communications Network for schematic and connector information. Refer to Audio System/Navigation for schematic and connector information.
Normal Operation and Fault Conditions

The TCU communicates on the HS-CAN4.

Possible Sources
- Fuse
- Wiring, terminals and connector
- TCU
Visual Inspection and Pre-checks
- Verify BCM fuse 10 (5A) is OK.

L1 CHECK THE TCU (TELEMATIC CONTROL UNIT MODULE) VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect: TCU C4803.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4803-1	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to L2

No	VERIFY the BCM fuse 10 (5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short.

L2 CHECK THE TCU (TELEMATIC CONTROL UNIT MODULE) GROUND CIRCUIT FOR AN OPEN

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4803-13	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to L3

No	REPAIR the circuit.

L3 CHECK THE HS-CAN4 (HIGH-SPEED CONTROLLER AREA NETWORK 4) CIRCUITS BETWEEN THE TCU (TELEMATIC CONTROL UNIT MODULE) AND THE GWM (GATEWAY MODULE A) FOR AN OPEN

Disconnect GWM C2431.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4803-8	Courtesy of FORD MOTOR COMPANY	C2431-7
C4803-16	Courtesy of FORD MOTOR COMPANY	C2431-6

Are the resistances less than 3 ohms?

Yes	CONNECT the GWM, GO to L4

No	REPAIR the circuit in question.

L4 CHECK FOR CORRECT TCU (TELEMATIC CONTROL UNIT MODULE) OPERATION

Ignition OFF.

Disconnect and inspect all the TCU connector.

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 TCU connector. Make sure it seats and latches correctly.

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

Is the concern still present?

Yes	CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA If a service article exists for this concern, DISCONTINUE this test and FOLLOW service article instructions. If no service articles address this concern, INSTALL a new TCU. REFER to: Telematics Control Unit (TCU) Module

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.