PINPOINT TEST Z : The Transfer Case Control Module (TCCM) Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. 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. Refer to Battery, Mounting and Cables .

Z1 CHECK THE TCCM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

Ignition OFF.

Disconnect: TCCM C2371A and C2371B .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371A-6	Courtesy of FORD MOTOR COMPANY	Ground
C2371A-7	Courtesy of FORD MOTOR COMPANY	Ground

Positive Lead	Measurement / Action	Negative Lead
C2371B-6 (Expedition only)	Courtesy of FORD MOTOR COMPANY	Ground
C2371B-7	Courtesy of FORD MOTOR COMPANY	Ground

Are the voltages greater than 11 volts?

Yes	GO to Z2.
No	VERIFY BJB fuse 20 (20A) (Expedition only), fuse 27 (20A), fuse 29 (10A) or BCM fuse 37 (10A) is OK. If OK, REPAIR the circuit in question. If not OK, REFER to the OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short.

Z2 CHECK THE TCCM GROUND CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect: Negative Battery Cable.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-3	Courtesy of FORD MOTOR COMPANY	Ground
C2371B-10 (Expedition only)	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms?

Yes	GO to Z3.
No	REPAIR the circuit in question.

Z3 CHECK THE HS-CAN CIRCUITS BETWEEN THE TCCM AND THE DLC FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371A-10	Courtesy of FORD MOTOR COMPANY	C251-6
C2371A-9	Courtesy of FORD MOTOR COMPANY	C251-14

Are the resistances less than 3 ohms?

Yes	CONNECT the negative battery cable. GO to Z4.
No	REPAIR the circuit in question. CONNECT the negative battery cable.

Z4 CHECK FOR CORRECT TCCM OPERATION

Ignition OFF.

Disconnect and inspect the TCCM connectors and related in-line connectors.

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

Reconnect the TCCM connectors and related in-line connectors. Make sure they seat and latch correctly.

Operate the system and verify the concern is still present.

Is the concern still present?

Yes	CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, discontinue this test and follow TSB instructions. If no TSBs address this concern, INSTALL a new TCCM. REFER to Four Wheel Drive (4WD) Systems .
No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.