ON-BOARD DIAGNOSTIC FUNCTION

• The on-board diagnostic system consists of a malfunction detection system that detects abnormalities in input/output signals, 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 GND in wiring harness between BCM and front door switch (driver side)
B1330	Passenger door ajar circuit short to ground	Short to GND in wiring harness between BCM and front door latch switch (passenger side)
B1342	BCM internal malfunction	BCM microcomputer malfunction
B1502	Turn signal left circuit short to ground	Short to GND in wiring harness between BCM and turn switch (LH)
B1506	Turn signal right circuit short to ground	Short to GND in wiring harness between BCM and turn switch (RH)
B1520	Bonnet switch circuit open	Open circuit in wiring harness between BCM and bonnet latch switch
B1566	Door ajar circuit short to ground	Short to GND in wiring harness between BCM and rear door switches
B1614	Rear wiper interval switch input circuit short to ground	Short to GND in wiring harness between BCM and rear wiper and washer switch (INT)
B1873	Hazard switch input circuit short to ground	Short to GND in wiring harness between BCM and hazard warning switch
B2218	Door lock switch circuit short to ground	Short to GND in wiring harness between BCM and door lock switches
B2574	Driver door lock switch short to ground	Short to GND in wiring harness between BCM and driver-side door lock-link switch
B2721	Liftgate ajar output short to ground	Short to GND 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 short to ground	Short to GND in wiring harness between BCM and brake fluid level sensor
C1295	Steering wheel angle sensor internal fault	BCM detects steering angle sensor internal abnormality (signal overflow)
C1307	Steering wheel angle sensor encoder ring defective	BCM detects 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 GND in wiring harness between BCM and steering angle sensor
C1444	Steering phase B circuit short to ground	Short to GND in wiring harness between BCM and steering angle sensor
C144A	Steering phase C circuit short to ground	Short to GND in wiring harness between BCM and steering angle sensor
C144B	Steering phase Z circuit short to ground	Short to GND 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
C144D	Steering phase Z circuit signal is not sensed	Open circuit in wiring harness between BCM and steering angle sensor
C1937	Steering wheel angle sensor offset failure	BCM lost steering angle initialization position
U0073	CAN system communication error	BCM or twisted pair malfunction

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 GND in wiring harness between BCM and front door switch (driver side)

B1330

Passenger door ajar circuit short to ground

Short to GND in wiring harness between BCM and front door latch switch (passenger side)

B1342

BCM internal malfunction

BCM microcomputer malfunction

B1502

Turn signal left circuit short to ground

Short to GND in wiring harness between BCM and turn switch (LH)

B1506

Turn signal right circuit short to ground

Short to GND in wiring harness between BCM and turn switch (RH)

B1520

Bonnet switch circuit open

Open circuit in wiring harness between BCM and bonnet latch switch

B1566

Door ajar circuit short to ground

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

B1614

Rear wiper interval switch input circuit short to ground

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

B1873

Hazard switch input circuit short to ground

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

B2218

Door lock switch circuit short to ground

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

B2574

Driver door lock switch short to ground

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

B2721

Liftgate ajar output short to ground

Short to GND 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 short to ground

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

C1295

Steering wheel angle sensor internal fault

BCM detects steering angle sensor internal abnormality (signal overflow)

C1307

Steering wheel angle sensor encoder ring defective

BCM detects 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 GND in wiring harness between BCM and steering angle sensor

C1444

Steering phase B circuit short to ground

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

C144A

Steering phase C circuit short to ground

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

C144B

Steering phase Z circuit short to ground

Short to GND 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

C144D

Steering phase Z circuit signal is not sensed

Open circuit in wiring harness between BCM and steering angle sensor

C1937

Steering wheel angle sensor offset failure

BCM lost steering angle initialization position

U0073

CAN system communication error

BCM or twisted pair malfunction

• 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)	Input/output part	BCM terminal
CCNT_GE	—	Perform the DTC inspection.	—
BONNET_SW	OPEN/CLOSE	Bonnet latch switch Note • “CLOSE” is displayed on vehicles with the theft-deterrent system.	1B
T_GATE_SW	OPEN/CLOSE	Liftgate latch switch	6S
DRSW_REAR	OPEN/CLOSE	Rear door switch	6Q, 6R
DRSW_RF	OPEN/CLOSE	Front door latch switch (RH)	6M
DRSW_LF	OPEN/CLOSE	Front door latch switch (LH)	6O
HAZARD	On/Off	Hazard warning switch	5M
RWASH_SW	On/Off	Rear washer switch	5O
PRK_BRK	On/Off	Parking brake switch	1K
WPINT_REAR	On/Off	Rear wiper and washer switch (INT)	3Q
TURN_SW_R	On/Off	Turn switch (RH)	3G
TURN_SW_L	On/Off	Turn switch (LH)	3D
LLSW_D	LOCK/UNLOCK	Driver-side door lock-link switch	5K, 5N
CLS_LOCK	LOCK/Off	Door lock switches (lock)	1H, 3R
BRK_FLUID	Low/Normal	Brake fluid level sensor	1D