Home/Mazda/CX-5/Mazda CX-5 I (2011-2015)/Repair manual/Communication Devices/Control System -- Body Control Module: Diagnosis
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Control System -- Body Control Module: Diagnosis Mazda CX-5 I

Communication Devices 3 illustrations ~335 words

FRONT BODY CONTROL MODULE (FBCM) INSPECTION

  1. Remove the fuse box cover. (See «RELAY AND FUSE BLOCK REMOVAL/INSTALLATION»(ref-615398-S32369581092014051000000) ).
  2. Remove the front body control module (FBCM) from the fuse box. (See «FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION»(ref-615428-S26487100972014051000000) ).
  3. Verify that the voltages of each of the terminals are as indicated in the «TERMINAL VOLTAGE TABLE (REFERENCE)»(ref-615428-S30358371632014051000000) . 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.

Front Body Control Module Terminal Voltage Chart. Scheme 54

Scheme 54: Front Body Control Module Terminal Voltage Chart
TerminalSignalConnected toMeasurement conditionsVoltage (V)Inspection item(s)
1APower supplyHAZARD 25 A fuseUnder any conditionB+HAZARD 25 A fuse Related wiring harness
1BPower supplyHAZARD 25 A fuseUnder any conditionB+HAZARD 25 A fuse Related wiring harness
1CIgnition power supplyClimate control unit A/C relay Seat warmer control unitIgnition switched ON (engine off)B+Climate control unit A/C relay Seat warmer control unit Related wiring harness
Ignition switched OFF (LOCK)1.0 or less
1DSignal groundBody groundUnder any condition1.0 or lessRelated wiring harness
1ERear turn light (RH) controlRear turn light (RH)Ignition switched ON (engine off)Turn switch at right turn light position1.0 or less <==> B+Rear turn light (RH) Related wiring harness
Turn switch is in position other than above1.0 or less
1FSide turn light (RH) controlSide turn light (RH)Ignition switched ON (engine off)Turn switch at right turn light position1.0 or less <==> B+Side turn light (RH) Related wiring harness
Turn switch is in position other than above1.0 or less
1GFront turn light (RH) controlFront turn light (RH)Ignition switched ON (engine off)Turn switch at right turn light position1.0 or less <==> B+Front turn light (RH) Related wiring harness
Turn switch is in position other than above1.0 or less
1H
1ILicense light controlTNS relayLight switch at TNS positionB+TNS relay Related wiring harness
Light switch at OFF position1.0 or less
1JParking light controlParking light (RH, LH)Light switch at TNS positionB+Parking light (RH, LH) Related wiring harness
Light switch at OFF position1.0 or less
1K
1LHorn relay controlHorn relayHorn switch not pressedB+Horn relay Related wiring harness
Horn switch pressed1.0 or less
1MHeadlight relay (LO) controlHeadlight relay (LO)Light switch at HEAD position1.0 or lessHeadlight relay (LO) Related wiring harness
Light switch is in position other than aboveB+
1N
1O (1)Theft-deterrent horn input signalRear 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 lessRear body control module (RBCM) Related wiring harness
Connect the M-MDS and turn off the "BG_HORN_RLY" using the rear body control module (RBCM) simulation function.B+
1PRear window defroster relay controlRear window defroster relayIgnition switched ON (engine off)Rear window defroster switch OFFB+Rear window defroster relay Related wiring harness
Rear window defroster switch ON1.0 or less
1Q
1R (1)Theft-deterrent horn power supplyR.WIPER 15 A fuseUnder any conditionB+R.WIPER 15 A fuse Related wiring harness
1S
1T (1)Theft-deterrent horn output signalTheft-deterrent hornM-MDS is connected and theft-deterrent is sounded using data monitor functionB+Theft-deterrent horn Related wiring harness
M-MDS is connected and theft-deterrent is not sounded using data monitor function1.0 or less
2AInterior light power supplyROOM 15 A fuseUnder any conditionB+ROOM 15 A fuse Related wiring harness
2BFront turn light (LH) controlFront turn light (LH)Ignition switched ON (engine off)Turn switch at left turn light position1.0 or less <==> B+Front turn light (LH) Related wiring harness
Turn switch is in position other than above1.0 or less
2C (2)Daytime running light controlDRL relayIgnition switched ON (engine off) and light switch OFFDaytime running light illuminatesB+DRL relay Related wiring harness
Daytime running light turns off1.0 or less
2DRear turn light (LH) controlRear turn light (LH)Ignition switched ON (engine off)Turn switch at left turn light position1.0 or less <==> B+Rear turn light (LH) Related wiring harness
Turn switch is in position other than above1.0 or less
2E
2FSide turn light (LH) controlSide turn light (LH)Ignition switched ON (engine off)Turn switch at left turn light position1.0 or less <==> B+Side turn light (LH) Related wiring harness
Turn switch is in position other than above1.0 or less
2G (3)LIN communicationRain sensor/auto-light sensorTerminal used for communication therefore determination based on terminal voltage is not possible.
2H
2ICAN_LCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
2JLIN communicationClimate control unitTerminal used for communication therefore determination based on terminal voltage is not possible.
2KCAN_HCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
2LCAN_LAFS control moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
2MIgnition power supplyC/U IG1 15 A fuseIgnition switched ON (engine off)B+C/U IG1 15 A fuse Related wiring harness
Ignition switched OFF (LOCK)1.0 or less
2NCAN_LCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
2O
2PCAN_HCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
2QBrake fluid level switch signalBrake fluid level sensorIgnition switched ON (engine off)Brake fluid level is less than MIN (brake fluid level sensor ON)1.0 or lessBrake fluid level sensor Related wiring harness
Brake fluid level is MIN or more (brake fluid level sensor OFF)Wave pattern (See PATTERN 1 ).
2RCAN_HCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
2SWasher level switch signalWasher fluid-level sensorIgnition switched ON (engine off)Washer level is less than MIN (washer fluid-level sensor ON)1.0 or lessWasher fluid-level sensor Related wiring harness
Washer level is MIN or more (washer fluid-level sensor OFF)Wave pattern (See PATTERN 1 ).
2T
2UIgnition power supplyStart stop unitIgnition switched ON (engine off)B+Start stop unit Related wiring harness
Ignition switched OFF (LOCK)1.0 or less
2VHeadlight relay (LO) control (discharge type)Headlight relay (LO)Light switch at HEAD position1.0 or lessHeadlight relay (LO) Related wiring harness
Light switch is in position other than aboveB+
2WHeadlight (LO) switch signalStart stop unitLight switch at HEAD position1.0 or lessStart stop unit Related wiring harness
Light switch at OFF positionB+
2XHeadlight relay (HI) controlHeadlight relay (HI)Headlight at HEAD position and dimmer switch at LO positionB+Headlight relay (HI) Related wiring harness
Headlight at HEAD position and dimmer switch at HIGH or passing position1.0 or less
2YWindshield wiper (LO) switch signalStart stop unitWindshield wiper switch at ON position1.0 or lessStart stop unit Related wiring harness
Windshield wiper switch at OFF positionB+
2ZBlower motor relay controlBlower relayIgnition switched ON (engine off)Operate blower motor using fan switch1.0 or lessBlower relay Related wiring harness
Press climate control unit OFF button to stop blower motorB+
2AAAutostop switch signalWindshield wiper motorIgnition switched ON (engine off)Turn windshield wiper switch ON and wiper is operatedB+Windshield wiper motor Related wiring harness
Windshield wiper switch OFF1.0 or less
2AB (4)Front fog light relay controlFront fog light relayLight switch at HEAD positionFront fog light switch OFFB+Front fog light relay Related wiring harness
Front fog light switch ON1.0 or less
3AWiper power supplyWIPER 20 A fuseUnder any conditionB+WIPER 20 A fuse Related wiring harness
3BWiper power supplyWIPER 20 A fuseUnder any conditionB+WIPER 20 A fuse Related wiring harness
3CWindshield wiper motor (HI) controlWindshield wiper motorIgnition switched ON (engine off)Windshield wiper switch at HI positionB+Windshield wiper motor Related wiring harness
Windshield wiper switch at OFF position1.0 or less
3DPower groundBody groundUnder any condition1.0 or lessRelated wiring harness
3EWindshield wiper motor (HI) controlWindshield wiper motorIgnition switched ON (engine off)Windshield wiper switch at HI positionB+Windshield wiper motor Related wiring harness
Windshield wiper switch at OFF position1.0 or less
3FWindshield washer motor controlWasher motorIgnition switched ON (engine off)Windshield washer switch ONB+Washer motor Related wiring harness
Windshield washer switch OFF1.0 or less
3GWindshield wiper motor (LOW) controlWindshield wiper motorIgnition switched ON (engine off)Windshield wiper switch at LOW positionB+Windshield wiper motor Related wiring harness
Windshield wiper switch at OFF position1.0 or less
3HRear window washer motor controlWasher motorIgnition switched ON (engine off)Rear window washer switch ONB+Washer motor Related wiring harness
Rear washer switch OFF1.0 or less
3IWindshield wiper motor (LOW) controlWindshield wiper motorIgnition switched ON (engine off)Windshield wiper switch at LOW positionB+Windshield wiper motor Related wiring harness
Windshield wiper switch at OFF position1.0 or less
3JInterior illumination power supplySelector illumination Climate control unit (vehicles with manual air conditioner system) Audio unit Clock springLight switch at TNS positionB+Selector illumination Climate control unit (vehicles with manual air conditioner) Audio unit Clock spring Related wiring harness
Light switch at OFF position___ (5)
3KPower supplyHAZARD 25 A fuseUnder any conditionB+HAZARD 25 A fuse Related wiring harness
3LPower supplyHAZARD 25 A fuseUnder any conditionB+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 (5) The measured voltage changes according to the tester specification, therefore determination based on terminal voltage is not possible.
(1)Vehicles with theft-deterrent system
(2)Vehicles with DRL system
(3)Vehicles with auto wiper system
(4)Vehicles with front fog light system
(5)The measured voltage changes according to the tester specification, therefore determination based on terminal voltage is not possible.

Scheme 55

Scheme 55: Pattern 1
  1. Terminal: Brake fluid level signal: 2Q (+) <==> ground (-) Washer level signal: 2S (+) <==> ground (-)
  2. Oscilloscope setting: 2 V/DIV (Y), 1 ms/DIV (X), DC range (Scheme 55): Brake And Washer Fluid Level Signal Voltage Waveform

REAR BODY CONTROL MODULE (RBCM) INSPECTION

  1. Disconnect the negative battery cable. (See «NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0]»(ref-615412-S04991947062014051000000) ).
  2. Remove the following parts: Trunk board (See «TRUNK BOARD REMOVAL/INSTALLATION»(ref-615455-S29131302172014051000000) ). Trunk end trim (See «TRUNK END TRIM REMOVAL/INSTALLATION»(ref-615455-S40973116952014051000000) ). Rear scuff plate (LH) (See «REAR SCUFF PLATE REMOVAL/INSTALLATION»(ref-615455-S30956965972014051000000) ). Trunk side trim (LH) (See «TRUNK SIDE TRIM REMOVAL/INSTALLATION»(ref-615455-S22359050062014051000000) ).
  3. Remove the rear body control module (RBCM) from the body with the connector connected. (See «REAR BODY CONTROL MODULE (RBCM) REMOVAL/INSTALLATION»(ref-615428-S18318289172014051000000) ).
  4. Connect the negative battery cable. (See «NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0]»(ref-615412-S04991947062014051000000) ).
  5. Verify that the voltages of each of the terminals are as indicated in the «TERMINAL VOLTAGE TABLE (REFERENCE)»(ref-615428-S02026829992014051000000) . 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.

Identifying Rear Body Control Module Connectors. Scheme 56

Scheme 56: Identifying Rear Body Control Module Connectors
TerminalSignalConnected toMeasurement conditionsVoltage (V)Inspection item(s)
1A
1BInterior light groundMap light Vanity mirror illuminationUnder any condition1.0 or lessMap light Vanity mirror illumination Related wiring harness
1C
1D
1EInterior light controlMap lightUnder any condition1.0 or lessMap light Related wiring harness
1F
1G
1HInterior light power supplyMap lightUnder any conditionB+Map light Related wiring harness
2A
2BPower supplyD.LOCK 25 A fuseUnder any conditionB+D.LOCK 25 A fuse Related wiring harness
2CDoor lock controlDoor lock actuatorLock driver-side door lock switch from unlock1.0 or less --> B+ --> 1.0 or lessDoor lock actuator Related wiring harness
Unlock driver-side door lock switch from lock1.0 or less
2D
2EDoor unlock controlDoor lock actuatorUnlock driver-side door lock switch from lock1.0 or less --> B+ --> 1.0 or lessDoor lock actuator Related wiring harness
Lock driver-side door lock switch from unlock1.0 or less
2F (1)Theft-deterrent horn relay controlFront body control module (FBCM)Connected to M-MDS and using data monitor function, theft-deterrent sound activates1.0 or lessFront body control module (FBCM) Related wiring harness
Connected to M-MDS and using data monitor function, theft-deterrent sound does not activateB+
2G (2)2-stage unlock system controlDoor lock actuatorPress transmitter unlock button two times (2-stage unlock system operation condition)B+ --> 1.0 or lessDoor lock actuator Related wiring harness
Except above1.0 or less
2H
2IIgnition power supplyMETER 1 10 A fuseIgnition switched ON (engine off)B+METER 1 10 A fuse Related wiring harness
Ignition switched OFF (LOCK)1.0 or less
2J
2K
2L
2MPower supplyR.WIPER 15 A fuseUnder any conditionB+R.WIPER 15 A fuse Related wiring harness
2N
2O
2PPower supplyROOM 15 A fuseUnder any conditionB+ROOM 15 A fuse Related wiring harness
3A
3BSerial communicationStart stop unitTerminal used for communication therefore determination based on terminal voltage is not possible.
3CFuel sensor groundFuel gauge sender unitUnder any condition1.0 or lessFuel gauge sender unit Related wiring harness
3DSerial communicationPower window main switchTerminal used for communication therefore determination based on terminal voltage is not possible.
3E
3FDoor lock switch signalDoor lock switchDoor lock switch unlocked1.0 or lessDoor lock switch Related wiring harness
Other4.5
Door lock switch locked2.2
3G
3HDriver-side door key cylinder switch signalDoor key cylinder switchDoor key cylinder is turned to unlock side1.0 or lessDoor key cylinder switch Related wiring harness
Other4.5
Door key cylinder is turned to lock side2.2
3IFuel sensor signalFuel gauge sender unitInspect the fuel gauge sender unit and related wiring harnesses because the terminal voltage at this terminal cannot be examined. (See FUEL GAUGE SENDER UNIT INSPECTION [2WD] ). (See FUEL GAUGE SENDER UNIT INSPECTION [AWD] ).
3JLock input (lock-link switch (passenger's side, rear door))Door lock-link switchThe passenger-side and rear doors are all locked4.6Door lock-link switch Related wiring harness
Among the passenger-side and rear doors, at least one door is unlocked1.0 or less
3K (3)Fuel sensor signal (sub)Fuel gauge sender unit (sub)Inspect the fuel gauge sender unit and related wiring harnesses because the terminal voltage at this terminal cannot be examined. (See FUEL GAUGE SENDER UNIT INSPECTION [AWD] ).
3LBonnet latch switch signalHood latch switchHood open (bonnet latch switch OFF)4.6Hood latch switch Related wiring harness
Hood is closed (bonnet latch switch ON)1.0 or less
3MUnlock input (front door lock-link switch (driver's door))Door lock-link switch (driver's door)Driver's door locked4.6Door lock-link switch (driver's door) Related wiring harness
Driver's door unlocked1.0 or less
3N
3OLock input (front door lock-link switch (driver's door))Door lock-link switch (driver's door)Driver's door locked1.0 or lessDoor lock-link switch (driver's door) Related wiring harness
Driver's door unlocked4.6
3P
3QRear door switch (RH) signalRear door switch (RH)Rear door (RH) open1.0 or lessRear door switch (RH) Related wiring harness
Rear door (RH) closedB+
3R
3SRear door switch (LH) signalRear door switch (LH)Rear door (LH) open1.0 or lessRear door switch (LH) Related wiring harness
Rear door (LH) closedB+
3T
3UFront door switch (passenger's door) signalFront door switch (passenger's door)Front door (passenger's door) open1.0 or lessFront door switch (passenger's door) Related wiring harness
Front door (passenger's door) closedB+
3V
3WFront door switch (driver's door) signalFront door switch (driver's door)Front door (driver's door) open1.0 or lessFront door switch (driver's door) Related wiring harness
Front door (driver's door) closedB+
3X
4ARear window wiper motor power supplyRear wiper motorIgnition switched ON (engine off)B+Rear wiper motor Related wiring harness
Ignition switched OFF (LOCK)1.0 or less
4BPower groundBody groundUnder any condition1.0 or lessRelated wiring harness
4CLiftgate lock actuator controlLiftgate lock actuatorPress liftgate opener switchB+ --> 1.0 or lessLiftgate lock actuator Related wiring harness
Except above1.0 or less
4DBrake light controlBrake light High-mount brake lightBrake pedal depressedB+Brake light High-mount brake light Related wiring harness
Brake pedal not depressed1.0 or less
4E
4FCargo compartment light power supplyCargo compartment lightUnder any conditionB+Cargo compartment light Related wiring harness
4GCAN_HCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
4H
4ICAN_HCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
4JCAN_LCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
4KLiftgate latch switch signalCargo compartment light switchLiftgate open1.0 or lessCargo compartment light switch Related wiring harness
Liftgate closedB+
4LCAN_LCAN system related moduleTerminal used for communication therefore determination based on terminal voltage is not possible.
4MLiftgate opener switch signalLiftgate opener switchLiftgate opener switch pressed1.0 or lessLiftgate opener switch Related wiring harness
Liftgate opener switch not pressed4.5
4N
4O
4PCargo compartment light controlCargo compartment lightCargo compartment light switched ONLiftgate open1.0 or lessCargo compartment light Related wiring harness
Liftgate closedB+
4Q
4RSignal groundBody groundUnder any condition1.0 or lessRelated wiring harness
4SBack-up light controlBack-up light (LH, RH) Auto dimming mirrorIgnition switched ON (engine off)Selector lever at R position (AT vehicle) Shift lever at R position (MT vehicle)B+Back-up light (LH, RH) Auto dimming mirror Related wiring harness
Other1.0 or less
4TRear wiper motor control (LO)Rear wiper motorRear wiper switch at ON1.0 or lessRear wiper motor Related wiring harness
Rear wiper switch at OFFB+
(1) Vehicles with theft-deterrent system (2) Vehicles with 2-stage unlock system (3) AWD vehicles
(1)Vehicles with theft-deterrent system
(2)Vehicles with 2-stage unlock system
(3)AWD vehicles