2002 MAZDA 6 warning light

ELECTRONIC 4WD CONTROL SYSTEM
M–13
M
4WD CONTROL MODUREA6E632227100205Function
•The 4WD control modure (4WD CM) calculates the optimal amount of torque distribution for the rear wheels
and outputs a corresponding electric current to the electronic control coupling (4WD solenoid). This calculation
is based on the throttle angle, four-wheel speed, engine speed, selector lever position, and other related input
signals, matched with the vehicle driving and road surface conditions.
Functions
Construction
•The 4WD CM is installed to the left of the brake pedal (clutch pedal position).
Block diagram
.
Function name Contents
4WD system control
function•Based on each input signal, the electronic control current sent to the electronic control coupling
(4WD solenoid) is optimally controlled.
Diagnostic system•If the self-diagnostic system detects a malfunction, the 4WD warning light illuminates to alert
the driver, and at the same time the system suspends control or performs other measures to
prevent a loss of driving stability and protect the system.
•The detected malfunction is stored as a DTC in the 4WD CM.
987
5
43
10
19
18
17
15
16
14
131112
6
1
2
A6E63222008
1Front
2PCM
3TCM
4 DSC HU/CM
5 4WD control modure (4WD CM)
6 4WD solenoid
7Transaxle
8Transfer
9 Propeller shaft
10 Front drive shaft11 Pilot clutch/pilot cam
12 Ball/main cam
13 Main clutch
14 Electronic control coupling
15 Rear differential
16 Rear drive shaft
17 Torque transmission path
18 Electric signal path
19 Solenoid activation

ELECTRONIC 4WD CONTROL SYSTEM
M–15
M
Operation
Normal control
•When starting off or accelerating during straight-ahead driving, torque transmitted to the rear wheels is
optimally controlled to ensure sufficient acceleration performance. Due to this, standing-start and acceleration
performance is improved.
•Also, in order to improve fuel economy when driving at a stable, consistent speed, torque transmitted to the
rear wheels is damped, and rear-wheel drive is controlled to maintain it close to that of the front wheels.
Tight cornering control
•When the 4WD CM determines, based on the four-wheel speed signal, that the vehicle is in tight cornering, it
reduces the torque transmitted to the rear wheels to avoid tight corner braking characteristics.
Integrated DSC control
•If a signal from the DSC HU/CM input to the 4WD CM indicates that ABS control is activated, the module
controls the torque transmitted to the rear wheels to prevent undue influence on ABS control.
•Also, when a coupling torque request signal is received from the DSC HU/CM, the module controls the torque
transmitted to the rear wheels to match the amount of requested torque.
Other control
•In case the rear differential oil temperature exceeds the specified amount, or when there is an unusually large
variation in the rotation speed of the front and rear wheels (ex. when trying to get unstuck), control is
temporarily suspended in order to protect the 4WD system. When this occurs the 4WD warning light flashes to
indicate the situation to the driver.
End Of Sie
CONTROLLER AREA NETWORK (CAN)A6E632227100207Outline
•The 4WD CM transmits/receives information using the CAN system. See Section T for detailed information
regarding the CAN system.
Operation
Transmitted information
•Coupling torque
•4WD system operating condition (warning light information)
Received information
•Four-wheel speed
•Throttle opening angle
•Engine speed
•ABS/DSC operating condition
•Gear position
•Selector lever position
•Coupling torque request
End Of Sie

M–16
ELECTRONIC 4WD CONTROL SYSTEM
ON-BOARD DIAGNOSTICA6E632227100208Outline
•The on-board diagnostic function allows for detecting malfunctions in the input/output signals when the ignition
key is at the ON position.
•The DLC-2, which combines the failure detection and detection maintenance connectors, has been adopted to
improve serviceability. By connecting a WDS or equivalent to the DLC-2, malfunction diagnosis can be carried
out.
•Using a WDS or equivalent DTCs can be retrieved or erased, depending on the screen display, thus improving
serviceability.
Block diagram
.
Self-diagnostic function
Failure detection function
•The failure detection function detects malfunctions in the input/output signal systems of the 4WD CM and
displays them when the ignition key is at the ON position.
•When the ignition key is turned to the ON position, the 4WD CM system begins operation, and the 4WD
warning light illuminates for 3 seconds while the function checks for open circuits. At the same time the function
monitors the condition of the power supply voltage and checks for internal malfunctions.
•Then, once the system is running, the function checks the operating conditions of the 4WD solenoid and the
differential oil temperature sensor at regular intervals to determine whether there is any malfunction.
•If any malfunction is detected during these diagnostic tests, the warning light illuminates according to the
malfunction to alert the driver. Also, a DTC is output to DLC-2 via the CAN line. Also, at the same time the
failure detection result is sent to the memory and fail-safe functions.
9
87
5
4
3
10
13
11
12
6
12
A6E63222010
1 Input part
2 Regular control area
3 Output part
4 Fail-safe function
5 Failure detection function
6 Memory function
7 Failure display function8 External tester communication function
9 Failure diagnosis function
10 4WD warning light
11 DLC-2
12 CAN
13 WDS or equivalent

ELECTRONIC 4WD CONTROL SYSTEM
M–17
M
Memory function
•This function stores DTCs for malfunctions of the input/output signal systems as determined by the failure
detection function. Once a DTC is stored, it is not cleared even if the input/output signal system malfunction
returns to normal when the ignition key is turned to the LOCK position (engine OFF).
•Since DTCs are stored in the non-volatile memory inside the 4WD CM, they are not cleared even if the battery
is disconnected. Therefore, it is necessary to clear the memory when maintenance has been completed. For
clearing DTCs, refer to the procedures in the Workshop Manual.
•When inspecting DTCs using a WDS or equivalent, only one memory stored DTC at a time can be displayed.
Therefore, when multiple DTCs have been stored, it is necessary to inspect for DTCs again after repairing and
clearing the present DTC to ensure that there are no more DTCs present in the memory.
Fail-safe function
•When the failure detection function determines that there is a malfunction, the 4WD warning light illuminates to
alert the driver. At this time, the fail-safe function suspends control or takes other measures to ensure that
driving stability is not lost.
X:Available
*1: Does not illuminate when only the coupling torque request signal from the DSC HU/CM cannot be received.*2: Only integrated DSC control is prohibited when only the coupling torque request signal from the DSC HU/CM
cannot be received.
External tester communication function
•This function allows for the storing and clearing of DTCs due to a communication link between the 4WD CM
and an external tester.
End Of Sie
DTC Malfunction location4WD warning
lightconditionDTC stored in
memoryControl condition
P1887 System wiring Illuminated X Stop
P1888 Differential oil temperature sensor Illuminated X Stop
U0100 PCM communication system Illuminated X Stop
U0101 TCM communication system Illuminated X Stop
U0121 DSC communication system
Illuminated
*1X
Stop*2

P–4
ABS/TCS
OUTLINEA6E692146444201•The construction and operation of ABS (ABS/TCS) is the same as that of the current Mazda6 (GG) L8, LF, L3
engine 2WD model, except for the following. (See Mazda6 Training Manual 3359-1*-02C.)
—Due to adoption of TCM, ABS (ABS/TCS) HU/CM sends 4-wheel speed signal to the TCM through CAN.
Structural View
.
ABS/TCS
5
3
1
2
6
7
5
3
6
8
4
4
7
9
10TCS
OFF
11
12
A6E6916W201
1 L.H.D.
2 R.H.D.
3 ABS wheel-speed sensor (front)
4 ABS sensor rotor (front)
5 ABS wheel-speed sensor (rear)
6 ABS sensor rotor (rear)7 TCS OFF switch
8 Instrument cluster
9 ABS warning light
10 Brake system warning light
11 TCS indicator light
12 TCS OFF light

ABS/TCS
P–5
P
System Diagram
.
End Of Sie
9
9
8
7
5
43
12
6
18
17
15
16
14
13
11
12
RF
FL
RR
RL
PCMG
E
FI Z
U
D
A
B
C
Y
AC
X
V O
R ADAB AA
ABS/TCS HU/CM
pP
9
10
19
920
A6E6921W201
1 IG switch
2SUS 15 A fuse
3 ABS 60 A fuse
4 Meter
5 ABS warning light
6 Brake system warning light
7 TCS OFF light
8 TCS indicator light
9CAN driver
10 Brake light11 Cruise actuator
12 TCS OFF switch
13 DLC-2
14 CAN-H
15 CAN-L
16 ABS Wheel-speed sensor
17 Battery
18 Brake switch
19 Audio unit, Wiper and washer switch, Car-navigation
unit, Auto leveling control unit
20 TCM, 4WD CM

P–6
DYNAMIC STABILITY CONTROL
OUTLINEA6E692067650201•The construction and operation of DSC is the same as that of the current Mazada6 2WD model, except for the
following:
— Due to the addition the 4WD model, DSC HU/CM uses the foward-G signal from the combine sensor to
control DSC.
—Due to adoption of the 4WD CM, DSC HU/CM sends a coupling torque request, a 4-wheel speed, and DSC
operation condition signal to the 4WD CM through CAN.
—Due to the adoption of TCM, DSC HU/CM sends a 4-wheel speed signal to the TCM through CAN.
Structural view
.
DYNAMIC STABILITY CONTROL
7
5
4
3
1
2
14
13
6
13
12
5
4
3
7
6
1011
9
14
8
8
15
A6E6920T004
1 L.H.D.
2 R.H.D.
3 DSC HU/CM
4 Wheel-speed sensor (front)
5 Sensor rotor (front)
6 Wheel-speed sensor (rear)
7 Sensor rotor (rear)
8 DSC OFF switch9 Instrument cluster
10 ABS warning light
11 DSC indicator light
12 DSC OFF light
13 Steering angle sensor
14 Combine sensor
15 Brake system warning light

DYNAMIC STABILITY CONTROL
P–7
P
Wiring Diagram
.
9
RF
FL
RR
RL
PCM
G
E
M
I
F
K
H
Q
NJ
P
S
T
V
O
Y
X
W
U
R
L
Z
AC
D
B
AG
AF
AE
AC
AA
AB
C
F
D
A
B
EDSC HU/CM
A
B
C
D
F
1
3
2
8
7
5
4
6
9
9
9
10
11
13
12
15
14
18
17
16
1920
2122
24
23
A6E6921W203
1 IG switch
2SUS 15A fuse
3 ABS 60 A fuse
4 Meter
5 ABS warning light
6 Brake system warning light
7 DSC OFF light
8 DSC indicator light
9CAN driver
10 Battery
11 Cruise actuator
12 DSC OFF switch13 DLC-2
14 CAN-H
15 CAN-L
16 Wheel-speed sensor
17 Combine sensor
18 Steering angle sensor
19 Brake switch
20 Brake light
21 Back-up light switch (MTX only)
22 Back-up light (MTX only)
23 Audio unit, Wiper and washer switch, Car-navigation
unit, Auto leveling control unit
24 TCM, 4WD CM