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

• 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 latch 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 warning 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-link switch short to ground	Short to GND in wiring harness between BCM and driver-side door lock-link switch
B257C	Front (passenger-side)/rear door lock-link switch circuit open	Open circuit in wiring harness between BCM and front (passenger-side)/rear 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
C1284	Oil pressure switch circuit failure	Open circuit in wiring harness between BCM and oil pressure switch
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
U0100	Communication error to PCM
U0101	Communication error to TCM
U0121	Communication error to DSC/RSC HU/CM
U0401	Receive erratic data from PCM	BCM receives the erratic data from PCM for 5 s or more, while the ignition is ON

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 latch 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 warning 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-link switch short to ground

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

B257C

Front (passenger-side)/rear door lock-link switch circuit open

Open circuit in wiring harness between BCM and front (passenger-side)/rear 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

C1284

Oil pressure switch circuit failure

Open circuit in wiring harness between BCM and oil pressure switch

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

U0100

Communication error to PCM

U0101

Communication error to TCM

U0121

Communication error to DSC/RSC HU/CM

U0401

Receive erratic data from PCM

BCM receives the erratic data from PCM for 5 s or more, while the ignition is ON

• 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
BRK_FLUID	Normal/Low	Brake fluid level sensor
CCNT_GE	—	Perform the DTC inspection.
CLS_LOCK	Off/LOCK	Door lock switches (lock)
DRSW_D	CLOSE/OPEN	Front door latch switch (driver-side)
DRSW_REAR	CLOSE/OPEN	Rear door switch
DRSW_P	CLOSE/OPEN	Front door latch switch (passenger-side)
HAZARD	Off/On	Hazard warning switch
HOOD_SW	CLOSE/OPEN	Bonnet latch switch Note • “CLOSE” is displayed on vehicles with the theft-deterrent system.
LLSW_D	UNLOCK/LOCK	Driver-side door lock-link switch
OIL_PRS_SW	Off/On	Oil pressure switch
PRK_BRK	Off/On	Parking brake switch
RWASH_SW	Off/On	Rear washer switch
T_GATE_SW	CLOSE/OPEN	Liftgate latch switch
TURN_SW_L	Off/On	Turn switch (LH)
TURN_SW_R	Off/On	Turn switch (RH)
WPINT_REAR	Off/On	Rear wiper and washer switch (INT)