Pinpoint Test X : The BCMB (Body Control Module B) Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2020 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

Refer to Module Communications Network for schematic and connector information. Refer to Power Windows for schematic and connector information.
Normal Operation and Fault Conditions

The BCMB communicates on the MS-CAN.

Possible Sources
- Fuse
- Wiring, terminals and connector
- BCMB
Visual Inspection and Pre-checks
- Verify BCM fuses 25 (20A) and 22 (5A) are OK.

X1 CHECK THE BCMB (BODY CONTROL MODULE B) VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect: BCMB C4368A.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4368A-1	Courtesy of FORD MOTOR COMPANY	Ground
C4368A-7	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to X2

No	VERIFY BCM fuses 25 (20A) and 22 (5A) are OK. If OK, REPAIR the circuit. If not OK, REFER to the Introduction to identify the possible causes of the circuit short.

X2 CHECK THE BCMB (BODY CONTROL MODULE B) GROUND CIRCUIT FOR AN OPEN

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4368A-13	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to X3

No	REPAIR the circuit.

X3 CHECK THE MS-CAN (MEDIUM SPEED-CONTROLLER AREA NETWORK) CIRCUITS BETWEEN THE BCMB (BODY CONTROL MODULE B) AND THE GWM (GATEWAY MODULE A) FOR AN OPEN

Disconnect: GWM C2431.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4368A-11	Courtesy of FORD MOTOR COMPANY	C2431-23
C4368A-23	Courtesy of FORD MOTOR COMPANY	C2431-22

Are the resistances less than 3 ohms?

Yes

GO to X4

No	REPAIR the circuit in question.

X4 CHECK FOR CORRECT BCMB (BODY CONTROL MODULE B) OPERATION

Ignition OFF.

Disconnect and inspect the BCMB 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 BCMB 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 the service article instructions. If no service articles address this concern, INSTALL a new BCMB. REFER to: Body Control Module B (BCMB) .

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.