ON-BOARD DIAGNOSTIC SYSTEM [ELECTRONIC 4WD CONTROL SYSTEM]

id0302a6108100


Outline

•  The on-board diagnostic system consists of the following functions:
―  A malfunction detection function that detects abnormalities in input/output signals when the ignition switch is at the ON position.
―  PID/data monitor function that reads out specified input/output signals.
―  A simulation function that allows for override operation of output parts.
•  The data link connector 2 (DLC-2), which groups together all the connectors used for malfunction diagnosis 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) has following functions:
―  PID/data monitor access
―  DTC clear using the display screen of the diagnostic tester

Block diagram

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Function


Malfunction detection function

•  The malfunction detection function detects malfunctions in the input/output signal system of the 4WD control module when the ignition switched ON or driving the vehicle.
•  The 4WD control module performs that the 4WD warning light illuminate for approx. 3.0 s when the ignition is switched ON. At the same time, the input/output signals of each part are monitored for malfunction diagnosis.


Malfunction indication function

•  When the malfunction detection function detects a malfunction, the 4WD warning light illuminates or flashes to alert the driver.
•  Using the external tester communication function, DTCs can be output to the DLC-2 via the CAN line. At the same time, malfunction detection results are sent to the memory function and fail-safe function.


Memory function

•  The memory function stores DTCs of malfunctions in input/output signal systems. With this function, once a DTC is stored it is not cleared after the ignition switch has been switched OFF, even if the malfunctioning signal system has returned to normal.
•  Since the 4WD control module has a built-in non-volatile memory, DTCs are not cleared even if the battery is removed. Therefore, it is necessary to clear the memory after performing repairs. Refer to the Workshop Manual for the DTC clearing procedure.


DTC table

X: Applicable
—: Not applicable

DTC

4WD warning light

Description

Fail-safe

Drive cycle

Self test type*1

Memory function
P164D:00
Illuminates
4WD control module configuration
X
—
C
X
P182F:00
flashes
4WD control module
X
—
C
X
P187B:00
Illuminates
4WD control module
X
—
C
X
P1886:00
Illuminates
4WD control module
X
—
C
X
P1887:11
Illuminates
System wiring
X
—
C
X
P1887:12
Illuminates
System wiring
X
—
C
X
P1887:13
Illuminates
System wiring
X
—
C
X
P1887:14
Illuminates
System wiring
X
—
C
X
P1888:11
Illuminates
Differential oil temperature sensor
X
—
C
X
P1888:15
Illuminates
Differential oil temperature sensor
X
—
C
X
P188A:00
flashes
4WD control module
X
—
C
X
U0001:88
Not illuminate
CAN line
X
—
C
X
U0100:00
Not illuminate
CAN line
X
—
C
X
U0101:00
Not illuminate
CAN line
X
—
C
X
U0121:00
Not illuminate
CAN line
X
—
C
X
U0401:68
Not illuminate
Signal error from PCM
X
—
C
X
U0402:68
Not illuminate
Signal error from TCM
X
—
C
X
U0415:68
Not illuminate
Signal error from DSC HU/CM
X
—
C
X
U2100:00
Illuminates
4WD control module configuration
X
—
C
X

*1  :C: CMDTC self test


Status byte for DTC

•  The status byte is the two-digit code (two digits after hyphen (-)) after the seven-digit DTC.
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•  The status byte is a code which indicates the pending code, current/past malfunction status, or warning illumination status.
•  The status byte can be read by performing a CMDTC self test using the Mazda Modular Diagnostic System (M-MDS).
•  For details on the status byte, refer to the explanation on the M-MDS when reading the DTC.


Fail-safe function

•  When the malfunction detection function determines a malfunction, the 4WD warning light illuminates or flashes to alert the driver. At this time, the fail-safe function controls as indicated in the fail-safe function table.

Fail-safe function table

DTC

4WD control
P164D:00
Control maintained by the specified data
P182F:00
Control paused (4WD protection condition)
P187B:00
Control paused (4WD protection condition)
P1886:00
Control disabled
P1887:11
Control disabled
P1887:12
Control disabled
P1887:13
Control disabled
P1887:14
Control disabled
P1888:11
Control disabled
P1888:15
Control disabled
P188A:00
Control paused (4WD protection condition)
U0001:88
Control disabled
U0100:00
Control disabled
U0101:00
Lost gear position signal: Control maintained by the specified data
Except above: Control disabled
U0121:00
Control disabled
U0401:68
Control disabled
U0402:68
Control maintained by the specified data
U0415:68
Control disabled
U2100:00
Control maintained by the specified data


Snapshot data

•  The snapshot data stores the currently detected DTC data.

—: Not applicable

Snapshot data item

Unit

Definition

Data read/use method

Corresponding data monitor items
AAT
°C, °F
Ambient air temperature
—
AAT
IC_VPWR
V
Instrument cluster power supply
•  The 4WD control module constantly receives the power supply voltage value of the instrument cluster sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the 4WD control module records the power supply voltage of the instrument cluster when the DTC was detected, and it is displayed in the M-MDS.
—
IG-ON_TIMER
hh:mm:ss*1
Elapsed time since ignition was switched ON
Note
•  The instrument cluster records the elapsed time since the ignition was switched ON.
•  The 4WD control module constantly receives the elapsed time since the ignition was switched ON sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the 4WD control module records the elapsed time since the ignition was switched ON when the DTC was detected, and it is displayed in the M-MDS.
—
PWR_MODE_KEY
Key Out/Key Recently Out/Key Approved (Position 0)/Post Accessory (Position 0)/Accessory (Position 1)/Post Ignition (Position 1)/Ignition On (Position 2)/Running (Position 2)/Running - Starting In Progress (Position 2)/Crank (Position 3)
•  Key Out: Ignition switched off
•  Key Recently Out (Position 0): Elapsed time within 3 s since ignition was switched off
•  Accessory (Position 1): Ignition is switched to ACC
•  Post Ignition (Position 2): Elapsed time within 3 s since ignition was switched ON
•  Ignition On (Position 2): Ignition switched ON (engine off)
•  Running (Position 2): Ignition switched ON (engine on)
•  Running - Starting: Cranking condition
•  The 4WD control module constantly receives the ignition switch status sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the 4WD control module records the ignition switch status when the DTC was detected, and it is displayed in the M-MDS.
—
RPM_STATUS
Engine Stop/
Under 1500 rpm/
Over 1500 rpm/
FAIL
Engine RPM status
•  The EPS control module constantly receives the ignition switch status sent via CAN signal from the instrument cluster.
•  If a DTC is detected, the EPS control module records the ignition switch status when the DTC was detected, and it is displayed in the M-MDS.
—
TOTAL_DIST
km, ft, mi
Accumulated total traveled distance from completion of vehicle until 4WD control module detects DTC (Odometer value in instrument cluster)
The distance traveled when the 4WD control module detected a DTC can be calculated by performing the following procedure.
1.  Verify the odometer value in the instrument cluster.
2.  Verify the snap shot data item TOTAL_DIST.
3.  Subtract 2 from 1.
—
TOTAL_TIME
hh:mm:ss*1
Accumulated total elapsed time since vehicle completion until 4WD control module detects a DTC
Note
•  When the ROOM fuse is removed, and the ignition is switched off, the time is not included in the elapsed time.
The elapsed time when the 4WD control module detected a DTC can be calculated by performing the following procedure.
1.  Verify the PID item TOTAL_TIME of the instrument cluster.
2.  Verify the snap shot data item TOTAL_TIME.
3.  Subtract 2 from 1.
—

*1  :Fractions of seconds may be indicated after the decimal point


PID/data monitor function

•  The PID/data monitor function is used for optionally selecting input/output signal monitor items preset in the 4WD control module and reading them out in real-time.

—: Not applicable

Monitor item (Mazda Modular Diagnostic System (M-MDS) display)

Definition

Unit/operation
AAT
Ambient air temperature
°C, °F
APP
Accelerator pedal position
%
CAL_TABLE
4WD calibration table
—
CUP_SOL
4WD solenoid duty cycle
%
GEAR
Gear position
1st/2nd/3rd/4th/5th/6th/7th/Park/Neutral/Drive/Reverse
OIL_TEMP
Differential oil temperature
°C, °F
RPM
Engine speed
RPM
SHIFT
Selector lever position
P/R/N/D/S/L
TORQUE
Total wheel torque
Nm
VPWR
Power supply
V
WARN_LAMP
4WD warning light status
OFF/ON/Blinking
WSPD_LF
LF ABS wheel-speed sensor
KPH, MPH
WSPD_LR
LR ABS wheel-speed sensor
WSPD_RF
RF ABS wheel-speed sensor
WSPD_RR
RR ABS wheel-speed sensor


Simulation function

•  The simulation function is used for optionally selecting simulation items of input/output parts preset in the 4WD control module, and to operate them regardless of control.

Simulation item

Output part

Operation

Operating condition
CUP_SOL
4WD solenoid
OFF/ON
Switch the ignition to ON (engine off or on)


External tester communication function

•  The external tester communication function enables communication of diagnostic data (DTC read-outs, input/output signal read-outs, operation of input/output parts) between the 4WD control module and an external tester.
•  By connecting the Mazda modular diagnostic system (M-MDS) to the DLC-2, diagnostic data can be sent and received between the Mazda modular diagnostic system (M-MDS) and the 4WD control module via CAN lines.
•  The 4WD control module receives the command signals of the malfunction detection function and PID/data monitor function from the Mazda modular diagnostic system (M-MDS), and sends DTCs and data regarding the operating status of each input/output part to the Mazda modular diagnostic system (M-MDS).

Diagnostic function name

Signal received

Signal sent
Malfunction detection function
DTC verification signal
DTC(s)
PID/data monitor function
Command signal to read selected monitor item
Monitored data for requested monitor item
Simulation function
Operation command signal for selected simulation item
Output part drive signal