2002 MAZDA 6 torque

ELECTRONIC 4WD CONTROL SYSTEM
M–11
M
4WD solenoid control current is ON
•When the 4WD solenoid control current is ON, current flows from the 4WD CM to the 4WD solenoid, and the
coupling operates in the following manner.
1. Magnetic flux forms at the electromagnetic coil of the 4WD solenoid.
2. Due to the magnetic flux in the armature, the pilot clutch is suctioned towards the magnetic coil side and
made to engage. This causes frictional torque to generate in the pilot clutch.
3. The torque is transmitted to the pilot cam, which is engaged with the pilot clutch.
4. A rotational difference is created between the pilot cam and the main cam. Due to this relative torsion, the
cam mechanism operates, transmitting torque from the pilot cam to the ball and then to the main cam. In
this way, the push force exerted on the main clutch is amplified.
5. As the main clutch engages, the drive torque from the front wheels is transmitted to the rear wheels.
•The amount of push force exerted on the main clutch by the main cam (that is, the strength of the drive torque
transmitted to the rear wheels) changes in accordance with the proportion of the force acting upon the pilot
cam, engaged with the pilot clutch. Therefore, by changing the periodicity of the electric current from the 4WD
CM to the 4WD solenoid (ON/OFF rate of the 4WD solenoid = force acting on the pilot cam), the module
controls the transmission of drive torque to the rear wheels.
.
End Of Sie
98
75
4
3
10
11
6
12
56
7
12
A6E63222005
1 Main clutch
2Pilot clutch
3 4WD solenoid (Electromagnetic coil)
4 4WD control modure (4WD CM)
5Main cam
6Pilot cam7Ball
8Armature
9 Drive torque
10 Magnetic flux
11 Input
12 Output

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

M–14
ELECTRONIC 4WD CONTROL SYSTEM
End Of Sie4WD SYSTEM CONTROLA6E632227100206Outline
Features
•Based on the inputted signals listed below, the 4WD CM calculates the optimal amount of torque distribution for
the rear wheels and outputs a corresponding electric control current to the electronic control coupling (4WD
solenoid).
•The module controls the current outputted to the 4WD solenoid by changing the rate of the ON/OFF timing.
Construction
Block diagram
.
Signal output part Signal name Note
PCMThrottle opening angle
Engine speed
Transmitted as a CAN signal TCMSelector lever position
Gear position
DSC HU/CMFour-wheel speed
DSC operating condition
Coupling torque request (DSC equipped vehicles)
Differential oil temperature
sensorRear differential oil temperature—
9
87
5
4
310
1413
11
12
61
2
A6E63222009
1PCM
2TCM
3 DSC HU/CM
4 Differential oil temperature sensor
5 Throttle opening angle
6 Engine speed
7 Selector lever position8 Gear position
9 Four-wheel speed
10 DSC operating condition
11 Coupling torque request (DSC equipped vehicles)
12 Rear differential oil temperature
13 4WD control modure (4WD CM)
14 Electronic control coupling (4WD solenoid)

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

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

GENERAL PROCEDURES
M–21
M
PRECAUTION (FRONT AND REAR AXLE)A6E631001018201Wheel and Tire Removal/Installation
1. The removal and installation procedures for the wheels and tires are not mentioned in this section. When a
wheel is removed, tighten it to 88—118 N·m {9.0—12.0 kgf·m, 65.0—87.0 ft·lbf}
Brake Line Disconnection/Connection
Caution
•Brake fluid will damage painted surfaces. If brake fluid gets on a painted surface, wipe it off
immediately.
1. Tighten the brake pipe flare nut using the SST (49 0259 770B). Be sure to modify the brake pipe flare nut
tightening torque to allow for use of a torque wrench-SST combination.
2. If any brake line has been disconnected any time during the procedure, add brake fluid, bleed the brakes, and
inspect for leakage after the procedure has been completed.
Suspension Arm Removal/Installation
1. Tighten any part of the suspension that uses rubber bushings only after vehicle has been lowered and
unloaded.
Note
•Unloaded: Fuel tank is full. Engine coolant and engine oil are at specified level. Spare tire, jack, and tools
are in designated position.
Connector Disconnection
1. Disconnect the negative (-) battery cable before disconnecting connectors.
Electronic Control 4WD System Parts
1. After servicing the electronic control 4WD system parts, verify that no DTC has been stored. Clear any DTCs
remaining in the memory.
End Of Sie
GENERAL PROCEDURES

M–48
REAR DRIVE SHAFT, REAR DIFFERENTIAL
5. Release any trapped air from the boots by
carefully lifting up the small end of each boot with
a cloth wrapped screwdriver.
Caution
•Do not let grease leak.
•Do not damage the boot.
6. Set the drive shaft to the standard length.
Standard length
mm {in}
7. Verify that the drive shaft length is within the standard.
•If not, repeat from Step 5.
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DIFFERENTIAL OIL INSPECTIONA6E6319271002031. Place the vehicle on level ground.
2. Remove the filler plug and washer.
3. Verify that the oil is at the brim of the filler plug
hole.
4. If it is low, add the specified oil.
5. Install a new washer and the filler plug, and
tighten.
Tightening torque
39.2—53.9 N·m {4.0—5.4 kgf·m, 29.0—39.7
ft·lbf}
End Of SieDIFFERENTIAL OIL REPLACEMENTA6E6319271002041. Place the vehicle on level ground.
2. Remove the filler plug.
3. Remove the drain plug and drain the differential
oil into a container.
4. Install a new washer and the drain plug, and
tighten.
Tightening torque
39—53 N·m {4.0—5.4 kgf·m, 29—39 ft·lbf}
5. Add the specified differential oil from the filler plug
until the level reaches the brim of the plug hole.
Specified oil
Type (API service GL-5)
Above -18°C {0°F}: SAE 90
Below -18°C {0°F}: SAE 80
Capacity (Approximate quantity):
1.00 L {1.06 US qt, 0.88 Imp qt}
6. After filling with differential oil, perform oil level inspection.
7. Install a new washer and the drain plug, and tighten.
Tightening torque
39.2—53.9 N·m {4.0—5.4 kgf·m, 29.0—39.7 ft·lbf}
Left side Right side
805.4—815.4
{31.71—32.10}852.4—862.4
{33.56—33.95}A6E6316W007
REAR DIFFERENTIAL
FILLER PLUG
A6E63192101
FILLER PLUG
DRAIN PLUG
A6E63192102

REAR DIFFERENTIAL
M–49
M
End Of SieOIL SEAL (SIDE GEAR) REPLACEMENTA6E6319271002051. Remove the drain plug and the drain differential oil into a container.
2. Install a new washer and the drain plug, and tighten.
3. Remove the rear drive shaft. (See M–43 REAR DRIVE SHAFT REMOVAL/INSTALLATION.)
4. Remove the clip from the drive shaft.
Caution
•Wrap the end of a screwdriver with cloth to prevent scratches to the inside of the differential
casing.
5. Remove the oil seal from the differential casing
using a screwdriver.
6. Apply differential oil to the new oil seal lip.
7. Install the new oil seal to the differential carrier
using the SSTs.
8. After installing the new clip onto the drive shaft,
insert the drive shaft into the differential. (See M–
43 REAR DRIVE SHAFT REMOVAL/
INSTALLATION.)
9. Verify that the drive shaft cannot be pulled out.
10. Add the specified differential oil.
11. fter adding the oil, perform an oil level inspection.
(See M–48 DIFFERENTIAL OIL INSPECTION.)
12. Install a new washer and the oil filler plug, and
tighten.
Tightening torque
39.2—53.9 N·m {4.0—5.4 kgf·m, 29.0—39.7 ft·lbf}
End Of Sie
OIL SEAL (COMPANION FLANGE) REPLACEMENTA6E6319271002061. Drain the differential oil into a container.
2. Remove the propeller shaft. (See L–5 PROPELLER SHAFT REMOVAL/INSTALLATION.)
3. Remove the locknut using the SST.
4. Support the differential using a jack.
A6A63192003
49 G030 79649 G030 797
A6A63192004
49 S120 710
A6A63192005