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Mazda 6. Manual - part 179

F–238

TROUBLESHOOTING

3. Inspect the operation sound is heard from cooling fan relay No.1 and cooling fan relay No.4.

— If the operation sound is not heard from cooling fan relay No.4, inspect cooling fan relay No.4 and

open circuit between PCM 4F and cooling fan relay No.4 wiring harnesses and connectors.

— If the operation sound is not heard from cooling fan relay No.1, inspect cooling fan relay No.1 and

between PCM terminal 4F and cooling fan relay No.1 wiring harnesses and connector.

— If the operation sound is heard from cooling fan relay No.1 and cooling fan relay No.4, inspect

wiring harnesses and connectors.

• If the cooling fan motor No.2 does not operate, perform the following:

— Inspect cooling fan motor No.2 and related wiring harnesses and connectors

• If the cooling fan motor No.2 does not operate, perform the following:

1. Select FAN2 PID.
2. Operate cooling fan relay No.3 by sending ON command.
3. Inspect the operation sound is heard from cooling fan relay No.3.

— If the operation sound is heard, inspect wiring harnesses and connectors.
— If the operation sound is not heard, inspect cooling fan relay No.3 and open circuit wiring harnesses

and connectors between PCM terminal 4B and cooling fan relay No.3.

Variable Air Duct (VAD) Control System Operation Inspection (L3 Engine Models)

1. Connect WDS or equivalent to DLC-2.
2. Access ECT, TP and RPM PIDs.
3. Start the engine.
4. Verify ECT PID is 70

°C {158°F} or over.

5. Inspect shutter valve operation following condition.

VAD shutter valve operation

• If the shutter valve operation is not specified, inspect as follows.

(1) Verify that DTC P1410 is not displayed.

• If DTC P1410 is shown, carry out DTC inspection.

(See

F–67 DTC TABLE

(2) Turn ignition switch to ON.
(3) Turn the VAD control solenoid valve from on to off using the VAD PID and verify that operation sound of the

solenoid valve is heard.

• If the operation sound is heard, inspect the following.

— Vacuum hose looseness or damage
— Vacuum chamber crack or damage
— Shutter valve actuator.

(See

F–12 VARIABLE AIR DUCT (VAD) SHUTTER VALVE INSPECTION (L3)

• Shutter valve stuck open or close

— If the operation sound is not heard, inspect following.
— VAD control solenoid valve.

(See

F–13 VARIABLE AIR DUCT (VAD) CONTROL SOLENOID VALVE INSPECTION (L3)

Engine speed

5,800 rpm with TP PID 50% or over

Below

Above

Shutter valve

Open

TROUBLESHOOTING

F–239

Variable Valve Timing Control System Operation Inspection
When idling cannot be continued

1. Remove the oil control valve (OCV) and verify that the spool valve is at maximum retard position.
2. If the spool valve is stuck in advance direction, replace the oil control valve (OCV).
3. Connect the oil control valve (OCV).
4. Turn the ignition switch on.
5. Verify that the spool valve is at maximum retard position.
6. If the spool valve is stuck in advance direction, inspect for the following.

• Short circuit in harnesses or connectors between the oil control valve (OCV) and the PCM.

7. Inspect the variable valve timing actuator.

When idling can be continued

1. Warn up the engine.
2. Connect WDS or equivalent to DLC-2.
3. Idle the engine.
4. Select VT DUTY1 PID.
5. Set the oil control valve (OCV) duty valve to 100% and verify that the engine idles roughly or stalls.

• If as specified, inspect the timing belt component (valve timing deviation).

• If not as specified, go to next step.

6. Remove the oil control valve (OCV) and connect the oil control valve (OCV) connector to the oil control valve

(OCV).

7. Turn ignition switch to ON.
8. Select VT DUTY1 PID.
9. Set the oil control valve (OCV) duty value to 100% and verify that the spool valve operates in the advance

direction.

10. If not as specified, inspect the following.

• Oil control valve (OCV) operation.

• Harnesses and connectors between the oil control valve (OCV) and the PCM for open or short.

11. Inspect the following hydraulic passages for clogging and/or leakage.

• Oil pressure switch—oil control valve (OCV)

• Oil control valve (OCV)—camshaft

• Camshaft internal passage

12. If they are okay, replace the intake camshaft pulley (with a built-in variable valve timing actuator).

End Of Sie

G–1

ENGINE ELECTRICAL SYSTEM