PINPOINT TEST P : The DSM Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2016 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 .

P1 CHECK THE DSM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

Ignition OFF.

Disconnect: DSM C341A and C341B .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C341A-1	Courtesy of FORD MOTOR COMPANY	Ground

Positive Lead	Measurement / Action	Negative Lead
C341B-1	Courtesy of FORD MOTOR COMPANY	Ground

Are the voltages greater than 11 volts?

Yes	GO to P2.
No	VERIFY the BCM fuse 7 (7.5) or BJB fuse 74 (30A) 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.

P2 CHECK THE DSM GROUND CIRCUIT FOR AN OPEN

Disconnect: Negative Battery Cable.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C341A-2	Courtesy of FORD MOTOR COMPANY	Ground

Positive Lead	Measurement / Action	Negative Lead
C341B-24	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances less than 3 ohms?

Yes	GO to P3.
No	REPAIR the circuit in question.

P3 CHECK THE MS-CAN CIRCUITS BETWEEN THE DSM AND THE DLC FOR AN OPEN

Disconnect: DSM C341D .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C341D-10	Courtesy of FORD MOTOR COMPANY	C251-3
C341D-9	Courtesy of FORD MOTOR COMPANY	C251-11

Are the resistances less than 3 ohms?

Yes	CONNECT the negative battery cable. GO to P4.
No	REPAIR the circuit in question. CONNECT the negative battery cable.

P4 CHECK FOR CORRECT DSM OPERATION

Ignition OFF.

Disconnect and inspect the DSM 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 DSM 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 DSM. REFER to Seating .
No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.