Mazda 3 Service Manual: Body Control Module (Bcm) Inspection
1. Remove the following parts:
a. Front scuff plate (LH).
b. Front side trim (LH).
c. Upper panel.
d. Shift knob (MTX).
e. Selector lever knob (ATX).
f. Shift panel.
g. Side wall.
h. Console.
2. Set the hood release lever out of the way..
3. Remove the lower panel. (driver-side).
4. Set the starter cut relay out of the way. (with advanced keyless entry and push button start system) (MTX).
5. Measure the voltage at each terminal is as indicated in the Terminal Voltage Tables.
-
If the voltage or continuity is not as specified in the Terminal Voltage Table, inspect the parts under Inspection item (s).
-
If the system does not work properly even though the parts or related wiring harnesses do not have any malfunction, replace the BCM.
Terminal Voltage Table (Reference)
|
Terminal |
Signal |
Connected to |
Measurement condition |
Voltage (V) |
Inspection item (s) |
|
|
1A |
CAN_H |
CAN system related module |
Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. |
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|
1B |
CAN_L |
CAN system related module |
Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. |
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|
1C |
Horn control |
Horn relay |
Horn not sounded |
B+ |
|
|
|
Horn sounded |
1.0 or less |
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|
1D |
Rear window defroster relay control |
Rear window defroster relay |
Switch the ignition to ON |
Rear window defroster switch on |
1.0 or less |
|
|
Rear window defroster switch off |
B+ |
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|
1E |
|
|
|
|
|
|
|
1F |
|
|
|
|
|
|
|
1G |
TNS control |
TNS relay |
Light switch at OFF position |
B+ |
|
|
|
Light switch at TNS position |
1.0 or less |
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|
1H |
Ambient temperature ground |
Ambient temperature sensor |
Under any condition |
1.0 or less |
|
|
|
1I |
Headlight relay (HI) control |
Headlight relay (HI) |
Light switch at HEAD position |
Light switch at LO position |
B+ |
|
|
Light switch at HI or PASS position |
1.0 or less |
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|
1J*1 |
Hood latch switch signal |
Hood latch switch |
Hood open (Hood latch switch off) |
Wave pattern. |
|
|
|
Hood closed (Hood latch switch on) |
1.0 or less |
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|
1K |
Headlight relay (LO) control |
Headlight relay (LO) |
Light switch at OFF position |
B+ |
|
|
|
Light switch at HEAD position |
1.0 or less |
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|
1L |
|
|
|
|
|
|
|
1M |
Front fog light relay control |
Front fog light relay |
Light switch at HEAD position |
Front fog light switch at off position |
B+ |
|
|
Front fog light switch at on position |
1.0 or less |
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|
1N |
Brake fluid level signal |
Brake fluid level sensor |
Switch the ignition to ON |
Brake fluid level below MIN. |
B+ |
|
|
Brake fluid level above MIN. |
1.0 or less |
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|
1O |
|
|
|
|
|
|
|
1P |
DRL relay control |
DRL relay |
Under any condition |
B+ |
|
|
|
1Q |
Back-up light switch signal |
Back-up light switch |
Switch the ignition to ON |
The selector lever is in the R position |
B+ |
|
|
Other |
1.0 or less |
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|
1R |
|
|
|
|
|
|
|
1S |
|
|
|
|
|
|
|
1T |
Headlight (HI) indicator control |
Headlight relay (HI) |
Light switch at HEAD position |
Light switch at LO position and HI beam indicator not illuminated in instrument cluster |
1.0 or less |
|
|
Light switch at HI or PASS position and Hi beam indicator illuminated in instrument cluster |
B+ |
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|
1U |
|
|
|
|
|
|
|
1V |
|
|
|
|
|
|
|
1W |
|
|
|
|
|
|
|
1X |
Ambient temperature sensor signal |
Ambient temperature sensor |
Switch the ignition to ON |
approx. 2.2 |
|
|
|
Switch the ignition to Off |
1.0 or less |
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|
2A |
CAN_H |
CAN system related module |
Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. |
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|
2B |
CAN_L |
CAN system related module |
Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. |
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|
2C*6 |
LIN signal |
Climate control unit |
Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. |
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|
2D |
Steering angle sensor ground |
Steering angle sensor |
Under any condition |
1.0 or less |
|
|
|
2E |
Steering angle sensor power supply |
Steering angle sensor |
Specified time elapsed since key removal and all doors closed |
Wave pattern. |
|
|
|
Other |
approx. 5 |
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|
2F |
Steering angle sensor signal (B) |
Steering angle sensor |
Turn the steering wheel to the left and right. |
Alternates between 4.004.75 and 0.250.75 |
|
|
|
2G |
Steering angle sensor signal (A) |
Steering angle sensor |
Turn the steering wheel to the left and right. |
Alternates between 4.004.75 and 0.250.75 |
|
|
|
2H |
Steering angle sensor signal (C) |
Steering angle sensor |
Turn the steering wheel to the left and right. |
Alternates between 4.004.75 and 0.250.75 |
|
|
|
2I |
Steering angle sensor signal (Z) |
Steering angle sensor |
Steering wheel is in center position |
0.250.75 |
|
|
|
Steering wheel is not in center position |
4.004.75 |
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|
2J |
Key reminder switch signal |
Key reminder switch |
Key inserted |
B+ |
|
|
|
Key removed |
1.0 or less |
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|
2K |
Rear wiper switch (INT) signal |
Windshield wiper and washer switch |
Switch the ignition to ON |
Rear wiper switch at INT position |
1.0 or less |
|
|
Rear wiper switch at OFF position |
B+ |
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|
2L |
Rear wiper switch (ON) signal |
Windshield wiper and washer switch |
Switch the ignition to ON |
Rear wiper switch at ON position |
1.0 or less |
|
|
Rear wiper switch at OFF position |
B+ |
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|
2M |
Hazard warning switch signal |
Hazard warning switch |
Hazard warning switch on |
1.0 or less |
|
|
|
Hazard warning switch off |
B+ |
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|
2N |
Signal ground |
Body ground |
Under any condition |
1.0 or less |
|
|
|
2O |
Turn switch input (RH) |
Turn switch |
Switch the ignition to ON |
Turn switch at right position |
1.0 or less |
|
|
Other |
B+ |
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|
2P |
Turn switch input (LH) |
Turn switch |
Switch the ignition to ON |
Turn switch at left position |
1.0 or less |
|
|
Other |
B+ |
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|
2Q |
Parking brake switch signal |
Parking brake switch |
Switch the ignition to ON |
Parking brake applied (Parking brake switch on) |
1.0 or less |
|
|
Parking brake not applied (Parking brake switch off) |
B+ |
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|
2R |
Rear window defroster switch signal |
Climate control unit |
Rear window defroster switch pressed |
1.0 or less |
|
|
|
Rear window defroster switch not pressed |
approx. 4.5 |
|||||
|
2S |
|
|
|
|
|
|
|
2T |
Headlight switch signal (HI) |
Light switch |
Light switch at HEAD position |
Light switch at LO position |
B+ |
|
|
Light switch at HI or PASS position |
1.0 or less |
|||||
|
2U |
Horn switch signal |
|
Horn switch is pressed |
1.0 or less |
|
|
|
Horn switch is not pressed |
B+ |
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|
2V |
Headlight switch signal (TNS) |
Light switch |
Light switch at TNS position |
1.0 or less |
|
|
|
Light switch at OFF position |
B+ |
|||||
|
2W |
Front fog light switch signal |
Front fog light switch |
Light switch at HEAD position |
Front fog Light switch at on position |
1.0 or less |
|
|
Front fog Light switch at off position |
B+ |
|||||
|
2X |
Headlight switch signal (LO) |
Light switch |
Light switch at HEAD position |
1.0 or less |
|
|
|
Light switch at OFF position |
B+ |
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|
3A |
Rear washer motor control |
Windshield washer motor |
Switch the ignition to ON |
Rear washer switch on |
B+ |
|
|
Rear washer switch off |
1.0 or less |
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|
3B |
|
|
|
|
|
|
|
3C |
Front washer motor control |
Windshield washer motor |
Switch the ignition to ON |
Windshield washer switch on |
B+ |
|
|
Windshield washer switch off |
1.0 or less |
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|
3D |
|
|
|
|
|
|
|
3E |
Front wiper motor (HI) control |
Windshield wiper motor |
Switch the ignition to ON |
Windshield wiper switch in HI position |
B+ |
|
|
Windshield wiper switch in off position |
1.0 or less |
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|
3F |
|
|
|
|
|
|
|
3G |
Auto stop switch signal |
Windshield washer motor |
Switch the ignition to ON |
Windshield wiper operating |
B+ |
|
|
Windshield wiper not operating |
1.0 or less |
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|
3H |
|
|
|
|
|
|
|
3I |
Front wiper motor (LO) control |
Windshield wiper motor |
Switch the ignition to ON |
Windshield wiper switch in LO position |
B+ |
|
|
Windshield wiper switch in off position |
1.0 or less |
|||||
|
3J |
Interior light power supply |
ROOM 15 A fuse |
Under any condition |
B+ |
|
|
|
3K |
Front turn light (LH) control |
Front turn light (LH) |
Front turn light (LH) flashes |
Alternates between 1.0 or less and B+ |
|
|
|
Front turn light (LH) not illuminated |
1.0 or less |
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|
3L |
Front turn light (RH) control |
Front turn light (RH) |
Front turn light (RH) flashes |
Alternates between 1.0 or less and B+ |
|
|
|
Front turn light (RH) not illuminated |
1.0 or less |
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|
4A |
Power door lock power supply |
D.LOCK 25 A fuse |
Under any condition |
B+ |
|
|
|
4B |
Power ground |
Body ground |
Under any condition |
1.0 or less |
|
|
|
4C |
IG2 |
F.WIPER 25 A fuse |
Switch the ignition to ON |
B+ |
|
|
|
Switch the ignition to Off |
1.0 or less |
|||||
|
4D |
Power ground |
Body ground |
Under any condition |
1.0 or less |
|
|
|
4E |
Ignition key illumination control |
Push button start illumination (with advanced keyless entry and push button start system) |
Switch the ignition to off and driver-side door opened or TNS ON. |
1.0 or less |
|
|
|
15 s or more after all doors closed and TNS off. |
B+ |
|||||
|
Ignition key illumination (with keyless entry system) |
Switch the ignition to off and driver-side door opened. |
1.0 or less |
|
|||
|
15 s or more after all doors closed. |
B+ |
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|
4F |
|
|
|
|
|
|
|
4G |
Rear window defroster indicator light control |
Climate control unit |
Switch the ignition to ON |
Rear window defroster switch pressed and rear window defroster indicator light illuminated |
1.0 or less |
|
|
Rear window defroster switch pressed and rear window defroster indicator light not illuminated |
B+ |
|||||
|
4H |
|
|
|
|
|
|
|
4I |
Front wiper switch (AUTO) signal (with auto wiper system) |
Windshield wiper and washer switch |
Switch the ignition to ON |
Windshield wiper switch in AUTO position |
1.0 or less |
|
|
Windshield wiper switch in off position |
B+ |
|||||
|
Front wiper switch (INT) signal (without auto wiper system) |
Switch the ignition to ON |
Windshield wiper switch in INT position |
1.0 or less |
|||
|
Windshield wiper switch in off position |
B+ |
|||||
|
4J |
Front wiper switch (LO) signal |
Windshield wiper and wash | ||||
Body Control Module (Bcm) Configuration
1. Connect the M-MDS to DLC-2.
2. After the vehicle is identified, select the following items from the initial
screen of the M-MDS.
When using the IDS (laptop PC)
Select ...
Body Control Module (Bcm) Removal/Installation
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Hot engines and engine oil can cause severe burns. Turn off the engine and
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A vehicle that is lifted but not securely supported on safety stands is dangerous.
It can slip or fall, causing death or serious injury. Never work ...
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49 0180 510B
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49 B034 001
Guide
49 B034 002
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...
Battery Inspection [Skyactiv G 2.0]
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Since battery acid is toxic, be careful when handling the battery.
Since battery acid is highly corrosive, be careful not to allow it to contact
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In case battery acid contacts skin, eyes, or clothing, flush it immediately
with running wa ...
