ON-BOARD DIAGNOSTIC FUNCTION [BODY CONTROL MODULE (BCM)]

ON-BOARD DIAGNOSTIC FUNCTION [BODY CONTROL MODULE (BCM)]SM1935618

• The on-board diagnostic system consists of a malfunction detection system that detects abnormalities in input/output signals and a data monitor function that reads out specified input/output signals.

• The data link connector 2 (DLC-2), which groups together all the connectors used for malfunction diagnosis and detecting/repair into a single location, has been adopted, thereby improving serviceability. Diagnosis is performed by connecting the Mazda Modular Diagnostic System (M-MDS) to the DLC-2.

• In addition to DTC read-out, the Mazda Modular Diagnostic System (M-MDS) is used to clear DTCs using the display screen of the diagnostic tester, and to access the PID/data monitor function, providing enhanced malfunction diagnosis and improved serviceability.

• The malfunction detection function detects malfunctions in the input/output signal system of the BCM.

DTC No.	Description	Detection condition
B1317	Battery voltage high	Input voltage from the battery is excessively high.
B1318	Battery voltage low	Input voltage from the battery is excessively low.
B1322	Driver door ajar circuit short to ground	Short to ground in wiring harness between BCM and front door switch (driver-side)
B1330	Passenger door ajar circuit short to ground	Short to ground in wiring harness between BCM and front door switch (passenger-side)
B1342	ECU is faulted	BCM microcomputer malfunction
B1502	Turn signal left circuit short to ground	Short to ground in wiring harness between BCM and turn switch
B1506	Turn signal right circuit short to ground	Short to ground in wiring harness between BCM and turn switch
B1520 ^*1	Bonnet latch switch circuit open	Open circuit in wiring harness between BCM and bonnet latch switch
B1566	Door ajar circuit short to ground	Short to ground in wiring harness between BCM and rear door switches
B1614	Rear wiper interval switch input circuit short to ground	Short to ground in wiring harness between BCM and rear wiper and washer switch (INT)
B1873	Hazard warning switch input circuit short to ground	Short to ground in wiring harness between BCM and hazard warning switch
B2175 ^*2	A/C request switch circuit short to ground	Short to ground in wiring harness between BCM and climate control unit (A/C ON request)
B2177 ^*1	Intruder sensor circuit failure	Intruder sensor circuit malfunction
B2218	Door lock switch circuit short to ground	Short to ground in wiring harness between BCM and door lock switches
B2477 ^*3	Module configuration failure	BCM data configuration error
B2574	Driver-side door lock-link switch circuit (lock-side) short to ground	Short to ground in wiring harness between BCM and driver-side door lock-link switch
B2665 ^*1	Theft-deterrent siren circuit failure	BCM cannot receive the theft-deterrent siren signal 5 times consecutively.
B2721	Liftgate ajar output circuit short to ground	Short to ground in wiring harness between BCM and liftgate latch switch
B2982	Parking brake switch circuit open	Open circuit in wiring harness between BCM and parking brake switch
C1189	Brake fluid level sensor input circuit short to ground	Short to ground in wiring harness between BCM and brake fluid level sensor
C1284	Oil pressure switch circuit failure	Open circuit in wiring harness between BCM and oil pressure switch
C1295	Steering angle sensor internal fault	BCM detects the steering angle sensor internal abnormality (signal overflow).
C1307	Steering angle sensor encoder ring defective	BCM detects the steering angle sensor internal abnormality (signal jump).
C1441	Steering phase A circuit signal is not sensed	Open circuit in wiring harness between BCM and steering angle sensor
C1442	Steering phase B circuit signal is not sensed	Open circuit in wiring harness between BCM and steering angle sensor
C1443	Steering phase A circuit short to ground	Short to ground in wiring harness between BCM and steering angle sensor
C1444	Steering phase B circuit short to ground	Short to ground in wiring harness between BCM and steering angle sensor
C144A	Steering phase C circuit short to ground	Short to ground in wiring harness between BCM and steering angle sensor
C144C	Steering phase C circuit signal is not sensed	Open circuit in wiring harness between BCM and steering angle sensor
C1937	Steering angle sensor offset failure	BCM lost the steering angle initialization position.
U0028 ^*1	CAN system communication error	BCM or twisted pair malfunction
U0073	CAN system communication error	BCM or twisted pair malfunction
U0100	Communication error with PCM	BCM cannot receive the signal from PCM for 5 s or more.
U0121 ^*3	Communication error with DSC HU/CM	BCM cannot receive the signal from DSC HU/CM for 5 s or more.

DTC No.

Description

Detection condition

B1317

Battery voltage high

Input voltage from the battery is excessively high.

B1318

Battery voltage low

Input voltage from the battery is excessively low.

B1322

Driver door ajar circuit short to ground

Short to ground in wiring harness between BCM and front door switch (driver-side)

B1330

Passenger door ajar circuit short to ground

Short to ground in wiring harness between BCM and front door switch (passenger-side)

B1342

ECU is faulted

BCM microcomputer malfunction

B1502

Turn signal left circuit short to ground

Short to ground in wiring harness between BCM and turn switch

B1506

Turn signal right circuit short to ground

Short to ground in wiring harness between BCM and turn switch

B1520 ^*1

Bonnet latch switch circuit open

Open circuit in wiring harness between BCM and bonnet latch switch

B1566

Door ajar circuit short to ground

Short to ground in wiring harness between BCM and rear door switches

B1614

Rear wiper interval switch input circuit short to ground

Short to ground in wiring harness between BCM and rear wiper and washer switch (INT)

B1873

Hazard warning switch input circuit short to ground

Short to ground in wiring harness between BCM and hazard warning switch

B2175 ^*2

A/C request switch circuit short to ground

Short to ground in wiring harness between BCM and climate control unit (A/C ON request)

B2177 ^*1

Intruder sensor circuit failure

Intruder sensor circuit malfunction

B2218

Door lock switch circuit short to ground

Short to ground in wiring harness between BCM and door lock switches

B2477 ^*3

Module configuration failure

BCM data configuration error

B2574

Driver-side door lock-link switch circuit (lock-side) short to ground

Short to ground in wiring harness between BCM and driver-side door lock-link switch

B2665 ^*1

Theft-deterrent siren circuit failure

BCM cannot receive the theft-deterrent siren signal 5 times consecutively.

B2721

Liftgate ajar output circuit short to ground

Short to ground in wiring harness between BCM and liftgate latch switch

B2982

Parking brake switch circuit open

Open circuit in wiring harness between BCM and parking brake switch

C1189

Brake fluid level sensor input circuit short to ground

Short to ground in wiring harness between BCM and brake fluid level sensor

C1284

Oil pressure switch circuit failure

Open circuit in wiring harness between BCM and oil pressure switch

C1295

Steering angle sensor internal fault

BCM detects the steering angle sensor internal abnormality (signal overflow).

C1307

Steering angle sensor encoder ring defective

BCM detects the steering angle sensor internal abnormality (signal jump).

C1441

Steering phase A circuit signal is not sensed

Open circuit in wiring harness between BCM and steering angle sensor

C1442

Steering phase B circuit signal is not sensed

Open circuit in wiring harness between BCM and steering angle sensor

C1443

Steering phase A circuit short to ground

Short to ground in wiring harness between BCM and steering angle sensor

C1444

Steering phase B circuit short to ground

Short to ground in wiring harness between BCM and steering angle sensor

C144A

Steering phase C circuit short to ground

Short to ground in wiring harness between BCM and steering angle sensor

C144C

Steering phase C circuit signal is not sensed

Open circuit in wiring harness between BCM and steering angle sensor

C1937

Steering angle sensor offset failure

BCM lost the steering angle initialization position.

U0028 ^*1

CAN system communication error

BCM or twisted pair malfunction

U0073

CAN system communication error

BCM or twisted pair malfunction

U0100

Communication error with PCM

BCM cannot receive the signal from PCM for 5 s or more.

U0121 ^*3

Communication error with DSC HU/CM

BCM cannot receive the signal from DSC HU/CM for 5 s or more.

• The PID/data monitor function is used for optionally selecting input/output signal monitor items preset in the BCM and reading them out in real-time.

PID/data monitor item	Unit/Condition (Tester display)	Operation Condition	Inspection item(s)	BCM terminal
ACSW	Off/On	• A/C switch turned on: On • A/C switch turned off: Off	Climate control unit (A/C switch)	3L
BRK_FLUID	Normal/Low	• Brake fluid level above MIN: Normal • Brake fluid level below MIN: Low	Brake fluid level sensor	1C
CCNT_GE	—	• DTCs detected: 1-255 • No DTCs detected: 0	Perform the DTC inspection.	—
CLS_LOCK	Off/LOCK	• All doors closed: LOCK • Any door open: Off	Door lock switches (lock)	5K, 5N
DRSW_REAR	OPEN/CLOSE	• Rear door open: OPEN • Rear door closed: CLOSE	Rear door lock-link switch	5E, 5D
HAZARD	Off/On	• Hazard warning switch turned on: On • Hazard warning switch turned off: Off	Hazard warning switch	3T
HOOD_SW ^*1	CLOSE/OPEN	• Bonnet open: OPEN • Bonnet closed: CLOSE	Bonnet latch switch	1B
LLSW_D	UNLOCK/LOCK	• Driver-side lock knob locked: LOCK • Driver-side lock knob unlocked: UNLOCK	Driver-side door lock-link switch	5G, 5J
OIL_PRS_SW	Off/On	• Oil pressure warning light illuminates: On • Oil pressure warning light goes out: Off	Oil pressure switch	1E
PRK_BRK	Off/On	• Parking brake depressed (Parking brake switch in the on position): On • Parking brake not depressed (Parking brake switch in the off position): Off	Parking brake switch	1A
T_GATE_SW	CLOSE/OPEN	• Liftgate open: OPEN • Liftgate closed: CLOSE	Liftgate latch switch	5T
TURN_SW_L	Off/On	• Turn switch is in the left position: On • Turn switch is in the off position: Off	Turn switch (LH)	3R
TURN_SW_R	Off/On	• Turn switch is in the right position: On • Turn switch is in the off position: Off	Turn switch (RH)	3P
WPINT_REAR	Off/On	• Rear wiper switch is in the INT position: On • Rear wiper switch is in the OFF position: Off	Rear wiper and washer switch (INT)	3X

PID/data monitor item

Unit/Condition

(Tester display)

Operation Condition

Inspection item(s)

BCM terminal

ACSW

Off/On

• A/C switch turned on: On

• A/C switch turned off: Off

Climate control unit (A/C switch)

BRK_FLUID

Normal/Low

• Brake fluid level above MIN: Normal

• Brake fluid level below MIN: Low

Brake fluid level sensor

CCNT_GE

—

• DTCs detected: 1-255

• No DTCs detected: 0

Perform the DTC inspection.

—

CLS_LOCK

Off/LOCK

• All doors closed: LOCK

• Any door open: Off

Door lock switches (lock)

5K, 5N

DRSW_REAR

OPEN/CLOSE

• Rear door open: OPEN

• Rear door closed: CLOSE

Rear door lock-link switch

5E, 5D

HAZARD

Off/On

• Hazard warning switch turned on: On

• Hazard warning switch turned off: Off

Hazard warning switch

HOOD_SW ^*1

CLOSE/OPEN

• Bonnet open: OPEN

• Bonnet closed: CLOSE

Bonnet latch switch

LLSW_D

UNLOCK/LOCK

• Driver-side lock knob locked: LOCK

• Driver-side lock knob unlocked: UNLOCK

Driver-side door lock-link switch

5G, 5J

OIL_PRS_SW

Off/On

• Oil pressure warning light illuminates: On

• Oil pressure warning light goes out: Off

Oil pressure switch

PRK_BRK

Off/On

• Parking brake depressed (Parking brake switch in the on position): On

• Parking brake not depressed (Parking brake switch in the off position): Off

Parking brake switch

T_GATE_SW

CLOSE/OPEN

• Liftgate open: OPEN

• Liftgate closed: CLOSE

Liftgate latch switch

TURN_SW_L

Off/On

• Turn switch is in the left position: On

• Turn switch is in the off position: Off

Turn switch (LH)

TURN_SW_R

Off/On

• Turn switch is in the right position: On

• Turn switch is in the off position: Off

Turn switch (RH)

WPINT_REAR

Off/On

• Rear wiper switch is in the INT position: On

• Rear wiper switch is in the OFF position: Off

Rear wiper and washer switch (INT)