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

id094000104300

• 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.

Malfunction Detection Function

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

DTC table

DTC No. | Description | Detection condition
--- | --- | ---
B1317 | • BCM power supply voltage from the battery is 16 V or more. | BCM power supply voltage high input
B1318 | • BCM power supply voltage from the battery is less than 9 V. | BCM power supply voltage low input
B1322 | • Short to ground in front door switch (driver-side) circuit with the front door (driver-side) closed (front door switch (driver-side) off). | Front door switch (driver-side) circuit malfunction
B1330 | • Short to ground in front door switch (passenger-side) circuit with the front door (passenger-side) closed (front door switch (passenger-side) off). | Front door switch (passenger-side) circuit malfunction
B1342 | • BCM detects the internal ECU malfunction. | BCM internal ECU malfunction
B1502 | • Short to ground in turn switch (LH) circuit with the turn switch off. | Turn switch (LH) circuit malfunction
B1506 | • Short to ground in turn switch (RH) circuit with the turn switch off. | Turn switch (RH) circuit malfunction
B1520 | • Open circuit in bonnet latch switch circuit with the bonnet closed (bonnet latch switch on). | Bonnet latch switch circuit malfunction
B1566 | • Short to ground in rear door switch (LH) or (RH) circuit with the rear doors closed (rear door switches off). | Rear door switch (LH)/(RH) circuit malfunction
B1614 | • Short to ground in rear wiper INT switch circuit with the rear wiper switch off. | Rear wiper INT switch circuit malfunction
B1873 | • Short to ground in hazard warning switch circuit with the hazard warning switch off. | Hazard warning switch circuit malfunction
B2218 | • Door lock switch (driver-side) or (passenger-side) circuit voltage is less than 3.75 V with the door lock switches off. | Door lock switch (driver-side)/(passenger-side) circuit malfunction
B2574 | • Short to ground in front door lock-link switch (driver-side) lock-side circuit with the front door lock-link switch (driver-side) unlocked. | Front door lock-link switch (driver-side) lock-side circuit malfunction
B257C | • Open circuit in front door lock-link switch (passenger-side), rear door lock-link switch (LH) or (RH) circuit with the door lock-link switches unlocked. | Front door lock-link switch (passenger-side)/rear door lock-link switch (LH)/(RH) circuit malfunction
B2721 | • Short to ground in liftgate latch switch circuit with the liftgate closed (liftgate latch switch off). | Liftgate latch switch circuit malfunction
B2982 | • Open circuit in parking brake switch circuit with the parking brake lever pulled (parking brake switch on). | Parking brake switch circuit malfunction
C1189 | • Short to ground in brake fluid level sensor circuit with the brake fluid level on the upper side of the MIN. | Brake fluid level sensor circuit malfunction
C1295 | • BCM detects the steering angle sensor internal abnormality (signal overflow). | Steering angle sensor internal malfunction
C1307 | • BCM detects the steering angle sensor internal abnormality (signal jump). | Steering angle sensor encoder ring defective
C1441 | • Open circuit in steering angle sensor A signal circuit. | Steering angle sensor A signal circuit malfunction
C1442 | • Open circuit in steering angle sensor B signal circuit. | Steering angle sensor B signal circuit malfunction
C1443 | • Short to ground in steering angle sensor A signal circuit. | Steering angle sensor A signal circuit malfunction
C1444 | • Short to ground in steering angle sensor B signal circuit. | Steering angle sensor B signal circuit malfunction
C144A | • Short to ground in steering angle sensor C signal circuit. | Steering angle sensor C signal circuit malfunction
C144B | • Short to ground in steering angle sensor Z signal circuit. | Steering angle sensor Z signal circuit malfunction
C144C | • Open circuit in steering angle sensor C signal circuit. | Steering angle sensor C signal circuit malfunction
C144D | • Open circuit in steering angle sensor Z signal circuit. | Steering angle sensor Z signal circuit malfunction
C1937 | • BCM lost the steering angle initialization position. | Steering angle sensor offset failure
U0073 | • BCM detects a CAN bus communication line (HS-CAN) malfunction. | Module communication error (HS-CAN)
U0100 | • BCM cannot receive the CAN signal from the PCM for 5 s or more. | Communication error with PCM
U0101 | • BCM cannot receive the CAN signal from the TCM for 5 s or more. | Communication error with TCM
U0121 | • BCM cannot receive the CAN signal from the DSC/RSC HU/CM for 5 s or more. | Communication error with DSC/RSC HU/CM
U0401 | • BCM receives the invalid data from the PCM for 5 s or more. | Error signal from PCM

PID/Data Monitor Function

• 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 above MIN: Normal • Brake fluid level below MIN: Low
CCNT_GEM | — | • DTCs detected: 1—255 • No DTCs detected: 0
CLS_LOCK | Off/Lock | • Any door open: Off • All doors closed: Lock
DRSW_D | Close/OPEN | • Front door (driver-side) closed: Close • Front door (driver-side) open: OPEN
DRSW_P | Close/OPEN | • Front door (passenger-side) closed: Close • Front door (passenger-side) open: OPEN
DRSW_REAR | Close/OPEN | • Rear door closed: Close • Rear door open: OPEN
HAZARD | Off/On | • Hazard warning switch turned off: Off • Hazard warning switch turned on: On
HOOD_SW | Close/OPEN | • Bonnet closed: Close • Bonnet open: OPEN Note • “CLOSE” is displayed on vehicles with the theft-deterrent system.
LLSW_D | Unlock/Lock | • Driver-side lock knob unlocked: Unlock • Driver-side lock knob locked: Lock
PRK_BRK | Off/On | • Parking brake not depressed (Parking brake switch in the off position): Off • Parking brake depressed (Parking brake switch in the on position): On
RWASH_SW | Off/On | • Rear washer switch in the off position: Off • Rear washer switch in the on position: On
T_GATE_SW | Close/OPEN | • Liftgate closed: Close • Liftgate open: OPEN
TURN_SW_L | Off/On | • Turn switch is in the off position: Off • Turn switch is in the LEFT position: On
TURN_SW_R | Off/On | • Turn switch is in the off position: Off • Turn switch is in the RIGHT position: On
WPINT_REAR | Off/On | • Rear wiper switch is in the OFF position: Off • Rear wiper switch is in the INT position: On