2002 MAZDA 6 ABS

ELECTRONIC 4WD CONTROL SYSTEM
M–69
M
1. Apply sealant to the coupling case surface that contacts the rear differential case.
2. Install the coupling unit to the rear differential so
that the two tabs on the coupling unit engage the
rear differential grooves (two locations).
Tightening torque
22.6—26.4 N·m {2.4—2.6 kgf·m, 16.7—19.4
ft·lbf}
End Of Sie
COUPLING COMPONENT DISASSEMBLYA6E632227100215
Warning
•The engine stand is equipped with a self-lock mechanism, however, if the coupling unit is in a
tilted condition, the self-lock mechanism could become inoperative. If the coupling unit
unexpectedly rotates it could cause injury, therefore do not maintain the coupling unit in a tilted
condition. When turning the coupling unit, grasp the rotation handle firmly.
.
GROOVE
REAR DIFFERENTIAL COUPLING UNITTA B
A6E63222108
SST
SST
SST
SST
9
8
75
4
3
1
2
10
6
A6J63222109
1 Locknut
(See M–70 Locknut Disassembly Note)
2Washer
3 Companion flange
(See M–70 Companion Flange Disassembly Note)
4 Output shaft
(See M–71 Output Shaft Disassembly Note)5 Coupling component
6Oil seal
7Shim
8 Retaining ring
9 Bearing
(See M–71 Bearing Disassembly Note)
10 Coupling case

M–76
ON-BOARD DIAGNOSTIC
ELECTRONIC 4WD CONTROL SYSTEM ON-BOARD DIAGNOSISA6E637027100202Reading DTCs Procedure
1. Connect WDS or equivalent to the vehicle DLC-2
16-pin connector.
2. Retrieve DTC by WDS or equivalent.
•If a DTC is displayed, proceed with inspection
steps for that DTC.
3. After repair, clear DTCs stored in the 4WD CM by
referring to the Clearing DTCs Procedure.
Clearing DTCs Procedures
1. Connect WDS or equivalent to the vehicle DLC-2
16-pin connector.
2. Clear DTCs by WDS or equivalent.
3. Turn the ignition key to OFF.
4. Perform the DTC inspection again, and verify that
no DTC appears.
5. Disconnect the WDS or equivalent.
DTC Table
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DLC-2
DLC-2
L.H.D.
R.H.D.
A6E63702005
DLC-2
DLC-2
L.H.D.
R.H.D.
A6E63702005
DTC
Diagnosis system component Page
WDS or equivalent
P1887 System wiring (See M–77 DTC P1887)
P1888 Differential oil temperature sensor (See M–79 DTC P1888)
U0100 PCM communication (See M–80 DTC U0100)
U0101 TCM communication (See M–80 DTC U0101)
U0121 ABS/DSC communication (See M–80 DTC U0121)

M–80
ON-BOARD DIAGNOSTIC
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DTC U0100A6E637027100205
Diagnostic Procedure
•Inspect according to the diagnostic procedure in Section T. (See T–39 MULTIPLEX COMMUNICATION
SYSTEM.)
End Of Sie
DTC U0101A6E637027100206
Diagnostic Procedure
•Inspect according to the diagnostic procedure in Section T. (See T–39 MULTIPLEX COMMUNICATION
SYSTEM.)
End Of Sie
DTC U0121A6E637027100207
Diagnostic Procedure
•Inspect according to the diagnostic procedure in Section T. (See T–39 MULTIPLEX COMMUNICATION
SYSTEM.)
End Of Sie
4INSPECT 4WD CM TO DIFFERENTIAL OIL
TEMPERATURE SENSOR FOR SHORT TO
GROUND
•Inspect for continuity between 4WD CM
terminal A and ground.
•Is there continuity?Yes Repair or replace harness for short to ground between 4WD
CM and differential oil temperature sensor, then go to Step
7.
No Go to next step.
5INSPECT 4WD CM TO DIFFERENTIAL OIL
TEMPERATURE SENSOR FOR OPEN
CIRCUIT
•Inspect for continuity between 4WD CM
terminal C and differential oil temperature
sensor terminal B.
•Is there continuity?Yes Go to next step.
No Repair or replace harness for open circuit between 4WD CM
and differential oil temperature sensor, then go to Step 7.
6INSPECT 4WD CM TO DIFFERENTIAL OIL
TEMPERATURE SENSOR FOR SHORT TO
GROUND
•Inspect for continuity between 4WD CM
terminal C and ground.
•Is there continuity?Yes Repair or replace harness for short to ground between 4WD
CM and differential oil temperature sensor, then go to next
step.
No Replace 4WD CM, then go to next step.
7VERIFY TROUBLESHOOTING COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from memory.
(See M–76 Clearing DTCs Procedures)
•Drive vehicle.
•Is the same DTC present?Yes Replace 4WD CM, then go to next step.
No Go to next step.
8VERIFY AFTER REPAIR PROCEDURE
•Is there any other DTC present?Yes Go to applicable DTC inspection.
No Troubleshooting completed. STEP INSPECTION ACTION
DTC U0100 PCM communication
DETECTION
CONDITION•4WD CM detects that communication signals (throttle opening angle and engine speed signals) from
PCM are abnormal.
POSSIBLE
CAUSE•PCM signals have communication error.
DTC U0101 TCM communication
DETECTION
CONDITION•4WD CM detects that communication signals (selector lever position and gear position signals) from
TCM are abnormal.
POSSIBLE
CAUSE•TCM signals have communication error.
DTC U0121 ABS/DSC communication
DETECTION
CONDITION•4WD CM detects that communication signals (four-wheel speed, ABS/DSC operation condition, and
coupling torque request signals) from DSC HU/CM are abnormal.
POSSIBLE
CAUSE•DSC HU/CM signals have communication error.

TROUBLESHOOTING
M–83
M
Diagnostic procedure
End Of Sie
NO.2 TIGHT CORNER BRAKINGA6E638027100205
Diagnostic procedure
STEP INSPECTION ACTION
1VERIFY DSC, PCM, TCM, AND 4WD SYSTEM
DTCs
•Verify DSC, PCM, TCM, and 4WD system
DTCs using WDS or equivalent.
•Are there any DTCs present?Yes Go to applicable DTC inspection.
No Go to next step.
2VERIFY TIRE AIR PRESSURE
•Inspect tire air pressure.
•Is it within specification?Yes Go to next step.
No Adjust tire air pressure, then go to next step.
3COMPARE WITH SAME MODEL TIRES
•Install tires of the same model.
•Perform simulation driving.
•Does malfunction recur?Yes Go to next step.
No 4WD system is okay.
4COMPARE WITH SAME MODEL VEHICLE
•Install tires of malfunctioning vehicle to
another same model vehicle.
•Perform simulation driving.
•Does malfunction recur?Yes 4WD system is okay.
No Go to next step.
5INSPECT 4WD SOLENOID
•Inspect 4WD solenoid.
(See M–66 4WD SOLENOID INSPECTION)
•Is coupling component solenoid okay?Yes Inspect harness between 4WD solenoid and 4WD CM, then
go to next step.
No Replace coupling component.
6INSPECT WHEEL ALIGNMENT
•Inspect wheel alignment.
•Is it okay?Yes Replace coupling component.
No Inspect wheel alignment, and adjust it if necessary.
2 Tight corner braking
[TROUBLESHOOTING HINTS]
•Because the coupling component locks up easily (similar to direct 4WD), rotational difference between the front
and rear wheels cannot be absorbed and brake-like phenomenon occurs.
•Due to the coupling component construction, slight tight corner braking effect occurs during tight cornering on a
paved road. (4WD system is okay. Compare with another same model vehicle to determine malfunction.)
•Coupling component malfunction
•4WD solenoid malfunction
STEP INSPECTION ACTION
1VERIFY DSC, PCM, TCM, AND 4WD SYSTEM
DTCS
•Verify DSC, PCM, TCM, and 4WD system
DTCs using WDS or equivalent.
•Are there any DTCs present?Yes Go to applicable DTC inspection.
No Go to next step.
2VERIFY TIRE AIR PRESSURE
•Inspect tire air pressure.
•Is it within specification?Yes Go to next step.
No Adjust tire air pressure, then go to next step.
3INSPECT ABS WHEEL-SPEED SENSOR
•Inspect ABS wheel-speed sensor.
•Is it okay?Yes Go to next step.
No Repair or replace malfunctioning part.
4COMPARE WITH SAME MODEL VEHICLE
•Perform simulation driving with another
same model vehicle.
•Does malfunction recur on the same model
vehicle?Yes 4WD system is okay.
No Go to next step.
5PERFORM SIMULATION DRIVING WITH 4WD
SOLENOID CONNECTOR DISCONNECTED
•Turn ignition key OFF.
•Disconnect 4WD solenoid connector.
•Perform simulation driving. (Clear DTC after
simulation driving.)
•Does malfunction recur?Yes Replace coupling component.
No Go to next step.

M–84
TROUBLESHOOTING
End Of Sie
NO.3 ABNORMAL NOISE AND/OR VIBRATION FROM COUPLING COMPONENTA6E638027100206
Diagnostic procedure
End Of Sie
6INSPECT 4WD SOLENOID
•Inspect 4WD solenoid.
(See M–66 4WD SOLENOID INSPECTION)
•Is it okay?Yes Inspect harness between 4WD solenoid and 4WD CM, then
go to next step.
No Replace coupling component. STEP INSPECTION ACTION
3 Abnormal noise and/or vibration from coupling component
[TROUBLESHOOTING HINTS]
•Abnormal noise and/or vibration from coupling component during driving
•Propeller shaft is malfunctioning or attached improperly.
•Engine mount or differential mount malfunction
•Resonance of rotating parts on vehicle (engine, propeller shaft, rear differential, tire, etc.)
•Resonance with engine vibration (mainly with exhaust system parts)
•Rear differential malfunction
•Coupling component malfunction
STEP INSPECTION ACTION
1VERIFY DSC, PCM, TCM, AND 4WD SYSTEM
DTCS
•Verify DSC, PCM, TCM, and 4WD system
DTCs using WDS or equivalent.
•Are there any DTCs present?Yes Go to applicable DTC inspection.
No Go to next step.
2VERIFY INSTALLATION CONDITION OF
VEHICLE PARTS
•Verify installation condition for following:
—Propeller shaft (including bending and
joint operation)
—Center bearing
—Engine mount
—Differential mount
—Hub bearing
—Exhaust system parts
—ABS wheel-speed sensor
•Are they properly installed?Yes Go to next step.
No Repair or replace malfunctioning part.
3DETERMINE IF MALFUNCTION IS CAUSED
BY REAR DIFFERENTIAL
•Install tires of another brand.
Note
•When tires of another brand are
installed, the same malfunction can
occur due to conditions different from
customer explanation. Be careful not
to confuse it with customer complaint.
•Perform simulation driving at the same
engine speed, gear position, and vehicle
speed that customer vehicle had
malfunction.
•Does the same malfunction occur?Yes Reinstall customer’s vehicle tire. Go to next step.
No 4WD system is okay.
Reinstall customer’s vehicle tire.
4INSPECT REAR DIFFERENTIAL
•Inspect rear differential for following:
—Backlash
—Teeth contact
(See M–56 REAR DIFFERENTIAL
ASSEMBLY)
•Are they okay?Yes Replace coupling component.
No Inspect malfunctioning part and adjust it if necessary.

N–8
ENGINE SPEED SENSING POWER STEERING
8. Open the gauge valve fully and increase the
engine speed to 1,000—1,500 rpm.
9. Turn the steering wheel fully to the left and right,
then measure the fluid pressure generated at the
gear housing.
•If the pressure is not within the specification,
repair or replace the steering gear
component.
Caution
•If the steering wheel is kept in the fully
turned position for more than 5 seconds,
the fluid temperature will rise excessively
and adversely affect the oil pump.
Gear housing fluid pressure
(MPa {kgf/cm
2, psi})
10. Remove the SSTs. Install and tighten the pressure pipe to the specified torque.
Tightening torque
29.4—44.1 N·m {3.0—4.4 kgf·m, 22—32 ft·lbf}
11. Bleed the air from the system.
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STEERING GEAR AND LINKAGE (MZR-CD (RF TURBO)) REMOVAL/INSTALLATIONA6E661432960201
Caution
•Performing the following procedures without first removing the ABS wheel-speed sensor may
possibly cause an open circuit in the harness if it is pulled by mistake. Before performing the
following procedures, remove the ABS wheel-speed sensor (axle side) and fix it to an appropriate
place where the sensor will not be pulled by mistake while servicing the vehicle.
L.H.D.
1. Remove the under cover and mud guard. (Left side)
2. Remove the front auto leveling sensor.
3. Separate the stabilizer control link. (shock absorber side)
4. Separate the front lower arm (front and rear) ball joint.
5. Remove the shock absorber bolt. (lower side)
6. Remove in the order indicated in the table.
7. Install in the reverse order of removal.
8. Inspect the toe-in.
9. Adjust the headlight zeroset.
Type Oil pump fluid pressure
2WD
(Except MZR-CD
(RF Turbo))10.80—11.29
{110.2—115.1, 1,567—1637}
MZR-CD
(RF Turbo)11.31—11.80
{115.4—120.3, 1,641—1,711}
4WD10.30—10.79
{105.1—110.0, 1,490—1,564}
THERMOMETER50—60
{122—140 }°
°F
GAUGE
OPEN VALVE
COMPLETELY
A6E0612W080

ENGINE SPEED SENSING POWER STEERING
N–13
N
STEERING GEAR AND LINKAGE (4WD) REMOVAL/INSTALLATIONA6E661432960202
Caution
•Performing the following procedures without first removing the ABS wheel-speed sensor may
possibly cause an open circuit in the harness if it is pulled by mistake. Before performing the
following procedures, remove the ABS wheel-speed sensor (axle side) and fix it to an appropriate
place where the sensor will not be pulled by mistake while servicing the vehicle.
1. Remove the under cover and mud guard. (Left side)
2. Remove the front auto leveling sensor.
3. Separate the stabilizer control link. (shock absorber side)
4. Separate the front lower arm (front and rear) ball joint.
5. Remove the shock absorber bolt. (lower side)
6. Remove in the order indicated in the table.
7. Install in the reverse order of removal.
8. Inspect the toe-in.
9. Adjust the headlight zeroset.

P–1
P
PBRAKING SYSTEM
OUTLINE................................................................ P-2
OUTLINE OF CONSTRUCTION.......................... P-2
FEATURES .......................................................... P-2
SPECIFICATIONS ............................................... P-2
STRUCTURAL VIEW ........................................... P-3
ABS/TCS................................................................ P-4
OUTLINE.............................................................. P-4
DYNAMIC STABILITY CONTROL......................... P-6
OUTLINE.............................................................. P-6
COMBINE SENSOR
(FORWARD-G SENSOR) ................................. P-8
CONTROLLER AREA NETWORK (CAN) ........... P-8
ON-BOARD DIAGNOSTIC..................................... P-9
OUTLINE.............................................................. P-9
OUTLINE.............................................................. P-10
SUPPLEMENTAL SERVICE INFORMATION ... P-10
GENERAL PROCEDURES.................................. P-10
PRECAUTION (BRAKES).................................. P-10
CONVENTIONAL BRAKE SYSTEM.................... P-11
POWER BRAKE UNIT
REMOVAL/INSTALLATION ............................ P-11
VACUUM SWITCH INSPECTION
(MZR-CD (RF TURBO)) .................................. P-11
VACUUM SWITCH
REMOVAL/INSTALLATION
(MZR-CD (RF TURBO)) .................................. P-12
VACUUM PUMP INSPECTION
(MZR-CD (RF TURBO)) .................................. P-12
VACUUM PUMP REMOVAL/INSTALLATION
(MZR-CD (RF TURBO)) .................................. P-13
FRONT BRAKE (DISC) INSPECTION............... P-13
FRONT BRAKE (DISC)
REMOVAL/INSTALLATION ............................ P-14
DISC PAD (FRONT) REPLACEMENT .............. P-16
PARKING BRAKE SYSTEM................................ P-17
PARKING BRAKE (LEVER TYPE)
ADJUSTMENT ................................................ P-17
DYNAMIC STABILITY CONTROL....................... P-17
DSC HU/CM INSPECTION ................................ P-17
COMBINE SENSOR
(FORWARD-G SENSOR) INSPECTION ........ P-20
ON-BOARD DIAGNOSTIC................................... P-21
DSC ON-BOARD DIAGNOSIS .......................... P-21
DTC C1119 ........................................................ P-26
DTC C1949, C1950............................................ P-27
DTC U2511 ........................................................ P-29 FEATURES
SERVICE