Mazda CX-5 Service & Repair Manual: Front Body Control Module (Fbcm) Inspection

Mazda CX-5 Service & Repair Manual / Electrical / Data Network / Front Body Control Module (Fbcm) Inspection

1. Remove the fuse box cover..

2. Remove the front body control module (FBCM) from the fuse box..

3. Verify that the voltages of each of the terminals are as indicated in the Terminal Voltage Table (Reference).

If the voltage is not as indicated in the table, inspect the parts under Inspection item(s).

If the system does not launch normally even though inspection items are normal, specify the location of the malfunction based on the instructions from the on-board diagnostic system and the symptom troubleshooting, and perform repairs.

Terminal Voltage Table (Reference)


Terminal	Signal	Connected to	Measurement conditions		Voltage (V)	Inspection item(s)
1A	Power supply	HAZARD 25 A fuse	Under any condition		B+	HAZARD 25 A fuse Related wiring harness
1B	Power supply	HAZARD 25 A fuse	Under any condition		B+	HAZARD 25 A fuse Related wiring harness
1C	Ignition power supply	Climate control unit A/C relay Seat warmer control unit	Ignition switched ON (engine off)		B+	Climate control unit A/C relay Seat warmer control unit Related wiring harness
1C	Ignition power supply	Climate control unit A/C relay Seat warmer control unit	Ignition switched OFF (LOCK)		1.0 or less
1D	Signal ground	Body ground	Under any condition		1.0 or less	Related wiring harness
1E	Rear turn light (RH) control	Rear turn light (RH)	Ignition switched ON (engine off)	Turn switch at right turn light position	1.0 or less ? B+	Rear turn light (RH) Related wiring harness
1E	Rear turn light (RH) control	Rear turn light (RH)	Ignition switched ON (engine off)	Turn switch is in position other than above	1.0 or less	Rear turn light (RH) Related wiring harness
1F	Side turn light (RH) control	Side turn light (RH)	Ignition switched ON (engine off)	Turn switch at right turn light position	1.0 or less ? B+	Side turn light (RH) Related wiring harness
1F	Side turn light (RH) control	Side turn light (RH)	Ignition switched ON (engine off)	Turn switch is in position other than above	1.0 or less	Side turn light (RH) Related wiring harness
1G	Front turn light (RH) control	Front turn light (RH)	Ignition switched ON (engine off)	Turn switch at right turn light position	1.0 or less ? B+	Front turn light (RH) Related wiring harness
1G	Front turn light (RH) control	Front turn light (RH)	Ignition switched ON (engine off)	Turn switch is in position other than above	1.0 or less	Front turn light (RH) Related wiring harness
1H	—	—	—		—	—
1I	License light control	TNS relay	Light switch at TNS position		B+	TNS relay Related wiring harness
1I	License light control	TNS relay	Light switch at OFF position		1.0 or less	TNS relay Related wiring harness
1J	Parking light control	Parking light (RH, LH)	Light switch at TNS position		B+	Parking light (RH, LH) Related wiring harness
1J	Parking light control	Parking light (RH, LH)	Light switch at OFF position		1.0 or less	Parking light (RH, LH) Related wiring harness
1K	—	—	—		—	—
1L	Horn relay control	Horn relay	Horn switch not pressed		B+	Horn relay Related wiring harness
1L	Horn relay control	Horn relay	Horn switch pressed		1.0 or less	Horn relay Related wiring harness
1M	Headlight relay (LO) control	Headlight relay (LO)	Light switch at HEAD position		1.0 or less	Headlight relay (LO) Related wiring harness
1M	Headlight relay (LO) control	Headlight relay (LO)	Light switch is in position other than above		B+	Headlight relay (LO) Related wiring harness
1N	—	—	—		—	—
1O*1	Theft-deterrent horn input signal	Rear body control module (RBCM)	Connect the M-MDS and turn on the "BG_HORN_RLY" using the rear body control module (RBCM) simulation function.		1.0 or less	Rear body control module (RBCM) Related wiring harness
1O*1	Theft-deterrent horn input signal	Rear body control module (RBCM)	Connect the M-MDS and turn off the "BG_HORN_RLY" using the rear body control module (RBCM) simulation function.		B+	Rear body control module (RBCM) Related wiring harness
1P	Rear window defroster relay control	Rear window defroster relay	Ignition switched ON (engine off)	Rear window defroster switch OFF	B+	Rear window defroster relay Related wiring harness
1P	Rear window defroster relay control	Rear window defroster relay	Ignition switched ON (engine off)	Rear window defroster switch ON	1.0 or less	Rear window defroster relay Related wiring harness
1Q	—	—	—		—	—
1R*1	Theft-deterrent horn power supply	R.WIPER 15 A fuse	Under any condition		B+	R.WIPER 15 A fuse Related wiring harness
1S	—	—	—		—	—
1T*1	Theft-deterrent horn output signal	Theft-deterrent horn	M-MDS is connected and theft-deterrent is sounded using data monitor function		B+	Theft-deterrent horn Related wiring harness
1T*1	Theft-deterrent horn output signal	Theft-deterrent horn	M-MDS is connected and theft-deterrent is not sounded using data monitor function		1.0 or less	Theft-deterrent horn Related wiring harness
2A	Interior light power supply	ROOM 15 A fuse	Under any condition		B+	ROOM 15 A fuse Related wiring harness
2B	Front turn light (LH) control	Front turn light (LH)	Ignition switched ON (engine off)	Turn switch at left turn light position	1.0 or less ? B+	Front turn light (LH) Related wiring harness
2B	Front turn light (LH) control	Front turn light (LH)	Ignition switched ON (engine off)	Turn switch is in position other than above	1.0 or less	Front turn light (LH) Related wiring harness
2C*2	Daytime running light control	DRL relay	Ignition switched ON (engine off) and light switch OFF	Daytime running light illuminates	B+	DRL relay Related wiring harness
2C*2	Daytime running light control	DRL relay	Ignition switched ON (engine off) and light switch OFF	Daytime running light turns off	1.0 or less	DRL relay Related wiring harness
2D	Rear turn light (LH) control	Rear turn light (LH)	Ignition switched ON (engine off)	Turn switch at left turn light position	1.0 or less ? B+	Rear turn light (LH) Related wiring harness
2D	Rear turn light (LH) control	Rear turn light (LH)	Ignition switched ON (engine off)	Turn switch is in position other than above	1.0 or less	Rear turn light (LH) Related wiring harness
2E	—	—	—		—	—
2F	Side turn light (LH) control	Side turn light (LH)	Ignition switched ON (engine off)	Turn switch at left turn light position	1.0 or less ? B+	Side turn light (LH) Related wiring harness
2F	Side turn light (LH) control	Side turn light (LH)	Ignition switched ON (engine off)	Turn switch is in position other than above	1.0 or less	Side turn light (LH) Related wiring harness
2G*3	LIN communication	Rain sensor/auto-light sensor	Terminal used for communication therefore determination based on terminal voltage is not possible.
2H	—	—	—		—	—
2I	CAN_L	CAN system related module	Terminal used for communication therefore determination based on terminal voltage is not possible.
2J	LIN communication	Climate control unit	Terminal used for communication therefore determination based on terminal voltage is not possible.
2K	CAN_H	CAN system related module	Terminal used for communication therefore determination based on terminal voltage is not possible.
2L	CAN_L	AFS control module	Terminal used for communication therefore determination based on terminal voltage is not possible.
2M	Ignition power supply	C/U IG1 15 A fuse	Ignition switched ON (engine off)		B+	C/U IG1 15 A fuse Related wiring harness
2M	Ignition power supply	C/U IG1 15 A fuse	Ignition switched OFF (LOCK)		1.0 or less	C/U IG1 15 A fuse Related wiring harness
2N	CAN_L	CAN system related module	Terminal used for communication therefore determination based on terminal voltage is not possible.
2O	—	—	—		—	—
2P	CAN_H	CAN system related module	Terminal used for communication therefore determination based on terminal voltage is not possible.
2Q	Brake fluid level switch signal	Brake fluid level sensor	Ignition switched ON (engine off)	Brake fluid level is less than MIN (brake fluid level sensor ON)	1.0 or less	Brake fluid level sensor Related wiring harness
2Q	Brake fluid level switch signal	Brake fluid level sensor	Ignition switched ON (engine off)	Brake fluid level is MIN or more (brake fluid level sensor OFF)	Wave pattern.	Brake fluid level sensor Related wiring harness
2R	CAN_H	CAN system related module	Terminal used for communication therefore determination based on terminal voltage is not possible.
2S	Washer level switch signal	Washer fluid-level sensor	Ignition switched ON (engine off)	Washer level is less than MIN (washer fluid-level sensor ON)	1.0 or less	Washer fluid-level sensor Related wiring harness
2S	Washer level switch signal	Washer fluid-level sensor	Ignition switched ON (engine off)	Washer level is MIN or more (washer fluid-level sensor OFF)	Wave pattern.	Washer fluid-level sensor Related wiring harness
2T	—	—	—		—	—
2U	Ignition power supply	Start stop unit	Ignition switched ON (engine off)		B+	Start stop unit Related wiring harness
2U	Ignition power supply	Start stop unit	Ignition switched OFF (LOCK)		1.0 or less	Start stop unit Related wiring harness
2V	Headlight relay (LO) control (discharge type)	Headlight relay (LO)	Light switch at HEAD position		1.0 or less	Headlight relay (LO) Related wiring harness
2V	Headlight relay (LO) control (discharge type)	Headlight relay (LO)	Light switch is in position other than above		B+	Headlight relay (LO) Related wiring harness
2W	Headlight (LO) switch signal	Start stop unit	Light switch at HEAD position		1.0 or less	Start stop unit Related wiring harness
2W	Headlight (LO) switch signal	Start stop unit	Light switch at OFF position		B+	Start stop unit Related wiring harness
2X	Headlight relay (HI) control	Headlight relay (HI)	Headlight at HEAD position and dimmer switch at LO position		B+	Headlight relay (HI) Related wiring harness
2X	Headlight relay (HI) control	Headlight relay (HI)	Headlight at HEAD position and dimmer switch at HIGH or passing position		1.0 or less	Headlight relay (HI) Related wiring harness
2Y	Windshield wiper (LO) switch signal	Start stop unit	Windshield wiper switch at ON position		1.0 or less	Start stop unit Related wiring harness
2Y	Windshield wiper (LO) switch signal	Start stop unit	Windshield wiper switch at OFF position		B+	Start stop unit Related wiring harness
2Z	Blower motor relay control	Blower relay	Ignition switched ON (engine off)	Operate blower motor using fan switch	1.0 or less	Blower relay Related wiring harness
2Z	Blower motor relay control	Blower relay	Ignition switched ON (engine off)	Press climate control unit OFF button to stop blower motor	B+	Blower relay Related wiring harness
2AA	Autostop switch signal	Windshield wiper motor	Ignition switched ON (engine off)	Turn windshield wiper switch ON and wiper is operated	B+	Windshield wiper motor Related wiring harness
2AA	Autostop switch signal	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch OFF	1.0 or less	Windshield wiper motor Related wiring harness
2AB*4	Front fog light relay control	Front fog light relay	Light switch at HEAD position	Front fog light switch OFF	B+	Front fog light relay Related wiring harness
2AB*4	Front fog light relay control	Front fog light relay	Light switch at HEAD position	Front fog light switch ON	1.0 or less	Front fog light relay Related wiring harness
3A	Wiper power supply	WIPER 20 A fuse	Under any condition		B+	WIPER 20 A fuse Related wiring harness
3B	Wiper power supply	WIPER 20 A fuse	Under any condition		B+	WIPER 20 A fuse Related wiring harness
3C	Windshield wiper motor (HI) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at HI position	B+	Windshield wiper motor Related wiring harness
3C	Windshield wiper motor (HI) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at OFF position	1.0 or less	Windshield wiper motor Related wiring harness
3D	Power ground	Body ground	Under any condition		1.0 or less	Related wiring harness
3E	Windshield wiper motor (HI) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at HI position	B+	Windshield wiper motor Related wiring harness
3E	Windshield wiper motor (HI) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at OFF position	1.0 or less	Windshield wiper motor Related wiring harness
3F	Windshield washer motor control	Washer motor	Ignition switched ON (engine off)	Windshield washer switch ON	B+	Washer motor Related wiring harness
3F	Windshield washer motor control	Washer motor	Ignition switched ON (engine off)	Windshield washer switch OFF	1.0 or less	Washer motor Related wiring harness
3G	Windshield wiper motor (LOW) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at LOW position	B+	Windshield wiper motor Related wiring harness
3G	Windshield wiper motor (LOW) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at OFF position	1.0 or less	Windshield wiper motor Related wiring harness
3H	Rear window washer motor control	Washer motor	Ignition switched ON (engine off)	Rear window washer switch ON	B+	Washer motor Related wiring harness
3H	Rear window washer motor control	Washer motor	Ignition switched ON (engine off)	Rear washer switch OFF	1.0 or less	Washer motor Related wiring harness
3I	Windshield wiper motor (LOW) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at LOW position	B+	Windshield wiper motor Related wiring harness
3I	Windshield wiper motor (LOW) control	Windshield wiper motor	Ignition switched ON (engine off)	Windshield wiper switch at OFF position	1.0 or less	Windshield wiper motor Related wiring harness
3J	Interior illumination power supply	Selector illumination Climate control unit (vehicles with manual air conditioner system) Audio unit Clock spring	Light switch at TNS position		B+	Selector illumination Climate control unit (vehicles with manual air conditioner) Audio unit Clock spring Related wiring harness
3J	Interior illumination power supply		Light switch at OFF position		1.0 or less
3K	Power supply	HAZARD 25 A fuse	Under any condition		B+	HAZARD 25 A fuse Related wiring harness
3L	Power supply	HAZARD 25 A fuse	Under any condition		B+	HAZARD 25 A fuse Related wiring harness

*1 Vehicles with theft-deterrent system

*2 Vehicles with DRL system

*3 Vehicles with auto wiper system

*4 Vehicles with front fog light system

Inspection Using an Oscilloscope (Reference)

Pattern 1

Terminal:

Brake fluid level signal: 2Q (+) ? ground (-)
Washer level signal: 2S (+) ? ground (-)

Oscilloscope setting: 2 V/DIV (Y), 1 ms/DIV (X), DC range

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