2002 MAZDA 6 Temperature control

K2–136
ON-BOARD DIAGNOSTIC
End Of Sie
4INSPECT TERMINAL COMPONENT NO.2 (8-
PIN) FOR POOR CONNECTION
•Turn ignition key to OFF.
•Inspect terminal component No.2 (8-pin)
connection.
•Disconnect terminal component No.2 (8-pin).
•Check for poor connection (damaged, pulled-
out terminals, corrosion etc.).
•Are connector and terminals okay?Yes Go to next step.
No Repair or replace connector and/or terminal, then go to
Step 11.
5INSPECT TFT SENSOR CIRCUIT
•Connect voltmeter to TCM terminal 1F.
•Turn ignition key to ON (engine OFF).
•Connect between terminal component No.2 (8-
pin) terminal H and G (harness-side) using
jumper wire.
•Verify if TCM terminal voltage changes to 0.2 V
or below.
•Does TCM terminal voltage change?Yes Go to next step.
No Go to Step 8.
6INSPECT COUPLER COMPONENT
CONNECTOR CONNECTION FOR POOR
CONNECTION
•Turn ignition key to OFF.
•Remove control valve body cover.
•Disconnect coupler component connector.
•Check for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Are terminals okay?Yes Go to next step.
No Repair or replace connector and/or terminal, then go to
Step 11.
7INSPECT COUPLER COMPONENT CIRCUIT
FOR OPEN CIRCUIT
•Check continuity between coupler component
(8-pin) terminals I and J (part-side).
•Is there continuity?Yes Repair or replace terminal component No.2 (8-pin).
No Replace TFT sensor, then go to Step 11.
(See K2–85 TRANSAXLE FLUID TEMPERATURE (TFT)
SENSOR REMOVAL/INSTALLATION.)
8INSPECT TCM CONNECTOR FOR POOR
CONNECTION
•Turn ignition key to OFF.
•Disconnect TCM connector.
•Check for poor connection (damaged, pulled-
out terminals, corrosion, etc.).
•Are terminals okay?Yes Go to next step.
No Repair terminals, then go to Step 11.
9INSPECT HARNESS FOR OPEN CIRCUIT
•Disconnect terminal component No.2 (8-pin)
•Connect the TCM connector.
•Turn ignition key to ON (engine OFF).
•Inspect voltage at terminal component No.2 (8-
pin) terminal G (harness-side).
•Is voltage 5 V?Yes Go to next step.
No Repair or replace harness, then go to Step 11.
10INSPECT TERMINAL COMPONENT NO.2 (8-
PIN) CIRCUIT FOR OPEN CIRCUIT
•Turn ignition key to OFF.
•Check continuity between terminal component
No.2 (8-pin) terminal H (harness-side) and
body ground.
•Is there continuity?Yes Go to next step.
No Repair or replace harness, then go to next step.
11VERIFY TROUBLESHOOTING OF DTC P0713
COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from memory using WDS or
equivalent.
•Drive vehicle for 150 seconds or more.
•Is same DTC present?Yes Replace TCM, then go to next step.
(See K2–96 TCM REMOVAL/INSTALLATION.)
No Go to next step.
12VERIFY AFTER REPAIR PROCEDURE
•Perform “After Repair Procedure”.
(See K2–124 AFTER REPAIR PROCEDURE.)
•Is there any DTC present?Yes Go to applicable DTC inspection.
No Troubleshooting completed. STEP INSPECTION ACTION

M–1
M
MFRONT AND REAR AXLES
OUTLINE............................................................... M-2
OUTLINE OF CONSTRUCTION ........................ M-2
FEATURES ......................................................... M-2
SPECIFICATIONS .............................................. M-2
REAR AXLE.......................................................... M-4
REAR AXLE OUTLINE ....................................... M-4
CROSS-SECTIONAL VIEW ............................... M-4
DRIVE SHAFT....................................................... M-5
DRIVE SHAFT OUTLINE.................................... M-5
STRUCTURAL VIEW.......................................... M-5
REAR DRIVE SHAFT ......................................... M-5
REAR DIFFERENTIAL.......................................... M-6
REAR DIFFERENTIAL OUTLINE ....................... M-6
CROSS-SECTIONAL VIEW ............................... M-6
ELECTRONIC 4WD CONTROL SYSTEM............ M-7
OUTLINE ............................................................ M-7
ELECTRONIC CONTROL COUPLING .............. M-9
DIFFERENTIAL OIL TEMPERATURE
SENSOR ........................................................ M-12
4WD WARNING LIGHT .................................... M-12
4WD CONTROL MODURE .............................. M-13
4WD SYSTEM CONTROL................................ M-14
CONTROLLER AREA NETWORK (CAN) ........ M-15
ON-BOARD DIAGNOSTIC ............................... M-16
OUTLINE............................................................. M-18
SUPPLEMENTAL SERVICE
INFORMATION .............................................. M-18
LOCATION INDEX.............................................. M-19
AXLE/DRIVE SHAFT LOCATION INDEX ......... M-19
REAR DIFFERENTIAL/ELECTRONIC
4WD CONTROL SYSTEM LOCATION
INDEX ............................................................ M-20
GENERAL PROCEDURES................................. M-21
PRECAUTION (FRONT AND REAR AXLE) ..... M-21
REAR AXLE........................................................ M-22
WHEEL HUB BOLT REPL
ACEMENT ..................................................... M-22
WHEEL HUB, KNUCKLE
REMOVAL/INSTALLATION ........................... M-22
FRONT DRIVE SHAFT........................................ M-29
JOINT SHAFT (MZR-CD (RF TURBO))
DISASSEMBLY/ASSEMBLY ......................... M-29
JOINT SHAFT (4WD)
DISASSEMBLY/ASSEMBLY ......................... M-31
FRONT DRIVE SHAFT
(MZR-CD (RF TURBO))
DISASSEMBLY/ASSEMBLY ......................... M-34
FRONT DRIVE SHAFT (4WD)
DISASSEMBLY/ASSEMBLY ......................... M-39REAR DRIVE SHAFT.......................................... M-42
REAR DRIVE SHAFT PRE-INSPECTION ........ M-42
REAR DRIVE SHAFT
REMOVAL/INSTALLATION ........................... M-43
REAR DRIVE SHAFT
DISASSEMBLY/ASSEMBLY ......................... M-45
REAR DIFFERENTIAL........................................ M-48
DIFFERENTIAL OIL INSPECTION ................... M-48
DIFFERENTIAL OIL REPLACEMENT .............. M-48
OIL SEAL (SIDE GEAR) REPLACEMENT ....... M-49
OIL SEAL (COMPANION FLANGE)
REPLACEMENT ............................................ M-49
REAR DIFFERENTIAL
REMOVAL/INSTALLATION ........................... M-51
REAR DIFFERENTIAL DISASSEMBLY ........... M-52
REAR DIFFERENTIAL ASSEMBLY ................. M-56
ELECTRONIC 4WD CONTROL SYSTEM.......... M-65
DIFFERENTIAL OIL TEMPERATURE
SENSOR INSPECTION ................................. M-65
DIFFERENTIAL OIL TEMPERATURE
SENSOR REMOVAL/INSTALLATION ........... M-65
4WD SOLENOID INSPECTION........................ M-66
4WD CONTROL MODURE INSPECTION ........ M-66
4WD CONTROL MODURE
REMOVAL/INSTALLATION ........................... M-67
COUPLING COMPONENT
REMOVAL/INSTALLATION ........................... M-68
COUPLING COMPONENT
DISASSEMBLY .............................................. M-69
COUPLING COMPONENT ASSEMBLY........... M-72
ON-BOARD DIAGNOSTIC.................................. M-75
WIRING DIAGRAM ........................................... M-75
ELECTRONIC 4WD CONTROL SYSTEM
ON-BOARD DIAGNOSIS ............................... M-76
DTC P1887 ....................................................... M-77
DTC P1888 ....................................................... M-79
DTC U0100 ....................................................... M-80
DTC U0101 ....................................................... M-80
DTC U0121 ....................................................... M-80
TROUBLESHOOTING......................................... M-81
SYSTEM WIRING DIAGRAM ........................... M-81
FOREWORD ..................................................... M-82
SYMPTOM TROUBLESHOOTING ................... M-82
NO.1 FREQUENT FRONT WHEEL SLIP ......... M-82
NO.2 TIGHT CORNER BRAKING .................... M-83
NO.3 ABNORMAL NOISE AND/OR
VIBRATION FROM COUPLING
COMPONENT ................................................ M-84 FEATURES
SERVICE

ELECTRONIC 4WD CONTROL SYSTEM
M–7
M
OUTLINEA6E632227100201Features
Improved off-road mobility, handling stability, operability, fuel economy and marketability
•An electronic 4WD control system, which automatically optimizes traction distribution to the front and rear
wheels, has been adopted.
Improved serviceability
•A self-diagnostic function has been adopted for the electronic 4WD control system.
Electronic 4WD control system outline
•The newly adopted electronic 4WD control system automatically and optimally controls drive torque distribution
for the front and rear wheels. Due to this off-road mobility, driving stability and fuel economy are improved.
•Based on the input signals from each sensor, the 4WD control modure (4WD CM) determines vehicle driving
and road conditions, and controls output current to the electronic control coupling (4WD solenoid) inside the
rear differential. This control allows for optimal distribution of the drive torque from the engine to the rear
wheels.
•Also, the 4WD CM automatically controls the 4WD, greatly reducing the load on the driver and improving
operability.
Structural view
.
ELECTRONIC 4WD CONTROL SYSTEM
87
5
4
3
6
9
8
7
5
4
3
10
6
1
2
9
10
A6E63222001
1L.H.D.
2 R.H.D.
3 4WD warning light
4 4WD control modure
5 DSC HU/CM6PCM
7TCM
8 Electronic control coupling (4WD solenoid)
9 Differential oil temperature sensor
10 Rear differential

M–8
ELECTRONIC 4WD CONTROL SYSTEM
Components and Functions
System Diagram
.
Part name Function
Electronic control coupling
(4WD solenoid)•Based on a signal from the 4WD CM, it operates the electromagnetic clutch and
transmits drive torque to the rear wheels.
Differential oil temperature
sensor•Informs the 4WD CM of the rear differential oil temperature.
4WD CM•Controls operation of the electronic control coupling (4WD solenoid) based on signals
input from the throttle opening angle, speed, differential oil temperature and other
sensors.
•Outputs coupling control condition and 4WD warning control information as a CAN
signal.
•Controls the on-board diagnostic system and the fail-safe system if there is a malfunction
in the 4WD system.
4WD warning light•Illuminates or flashes to alert driver of a malfunction or control failure in the 4WD system.
PCM•Sends the throttle opening angle and engine speed signals, as CAN signals, to the 4WD
CM.
TCM•Sends the selector lever position and gear position signals, as CAN signals, to the 4WD
CM.
DSC HU/CM•Sends the four-wheel speed and DSC operating condition signals, as CAN signals, to the
4WD CM.
•Sends the coupling torque request signal, as a CAN signal, to the 4WD CM.
KO
P I
A
C
NH G
9
8
7
5
4
3
10
13
11
12
6
1
2
A6E63222002
1 Battery
2 Ignition switch
3 Differential oil temperature sensor
4 4WD control modure (4WD CM)
5 Electronic control coupling
6 4WD solenoid
7 Instrument cluster8 DSC HU/CM
9TCM
10 PCM
11 CAN-H
12 CAN-L
13 CAN driver

M–12
ELECTRONIC 4WD CONTROL SYSTEM
DIFFERENTIAL OIL TEMPERATURE SENSORA6E632227100203Function
•The differential oil temperature sensor detects the rear differential oil temperature based on the resistance of
the thermistor, and inputs it to the 4WD control modure (4WD CM).
Construction/Operation
•The differential oil temperature sensor is installed in the rear differential carrier.
•The differential oil temperature sensor uses a thermistor whose resistance changes according to changes in
the rear differential oil temperature.
•The resistance grows smaller as the oil temperature rises and vice-versa, as shown.
.
End Of Sie
4WD WARNING LIGHTA6E632227100204Construction
•The 4WD warning light is built into the instrument cluster.
•If the self-diagnostic function stores a DTC, the warning light illuminates to alert the driver of the malfunction. If
system control is temporarily suspended due to the rear differential oil temperature becoming abnormally hot or
similar cause, the warning light flashes to alert the driver.
•The 4WD CM controls the operation of the warning light.
.
End Of Sie
5
4
3
1
2
A6E63222006
1 Differential oil temperature sensor characteristic
2 Resistance (ohm)
3 Temperature (°C {°F})4 Larger
5 Higher
1
A6E63222007
1 4WD warning light

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

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
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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