Mazda 6. Manual - part 178

F–234

TROUBLESHOOTING

A/C Cut-off Control System Inspection

1. Start the engine.
2. Turn the A/C switch and fan switch on.
3. Verify that the A/C compressor magnetic clutch actuates.

• If it does not actuate, go to symptom troubleshooting “No.23 A/C does not work sufficiently“.

4. Fully open the throttle valve and verify that the A/C compressor magnetic clutch does not actuate for 2—5

seconds.

• If it actuates, inspect as follows.

(1) Connect WDS or equivalent to the DLC-2.
(2) Turn the A/C switch off.
(3) Turn the ignition switch to ON position.
(4) Select ACCS PID.
(5) Turn the A/C relay from off to on and inspect if the operation sound of the relay is heard.

• If the operation sound is heard, inspect TP PID.

• If the operation sound is not heard, inspect following.

— A/C relay
— Open or short to GND circuit in wiring harness and connectors (Ignition switch-A/C relay-PCM

terminal 4O)

— A/C related parts

Cooling Fan Control System Inspection
L8, LF (General area) engine model

Cooling fan system operation

Cooling fan relay No.1

1. Connect WDS or equivalent to DLC-2.
2. Verify that ECT PID is below cooling fan operating temperature.
3. Verify that A/C switch and fan switch are off.
4. Turn the ignition switch to ON position.
5. Verify that the cooling fan is not operating.

• If the cooling fan No.1 is operating:

(1) Select FAN3 PID.
(2) Send OFF and verify the cooling fan is off.

• If the cooling fan is on, inspect the following.

— Cooling fan relay stuck in closed position
— Short to GND circuit between cooling fan relay and PCM terminal 4L
— Short to power in circuit at cooling fan relay
— DTC for ECT sensor (P0117, P0118)

• If the cooling fan is off, inspect the following.

— Short to GND circuit between refrigerant pressure switch and PCM terminal 1AC
— DTC for ECT sensor (P0117, P0118)

6. Start the engine.
7. Verify that the cooling fan is operating when engine is hot.

• If the cooling fan does not operate, perform the following.

1. Connect WDS or equivalent to the DLC-2.
2. Select FAN3 PID.
3. Operate cooling fan by sending ON command.

Engine condition

Cooling fan

relay No.1

Cooling fan

relay No.2

ECT below 100

°C

{212

°F}

OFF

ECT above 100

°C

{212

°F} (until below

°C {207°F})

OFF

ECT above 108

°C

{228

°F} (until below

105

°C {230°F})

A/C and fan switches
are on.

ECT sensor
malfunction

TROUBLESHOOTING

F–235

4. Inspect if the operation sound is heard from the cooling fan relay.

• If the operation sound is heard, inspect the wiring harness, connectors and cooling fan motor.

• If the operation sound is not heard, inspect cooling fan relay and open circuit wiring harness and

connectors.

8. Turn the A/C switch and fan switch on.
9. Verify that cooling fan is operating.

• If fan does not operate, inspect A/C system.

Cooling fan relay No.2

1. Verify that A/C switch and fan switch are off.
2. Start the engine and let it idle.
3. Verify that the cooling fan No.2 is not operating.

• If condenser fan is operating, inspect for the following.

— Cooling fan relay No.2 is stuck in closed position.
— Short to power in circuit between condenser fan relay and condenser fan
— Short to GND in circuit between refrigerant pressure switch and PCM terminal 1AC
— Short to GND circuit between condenser fan relay and PCM terminal 4B

4. Turn the A/C switch and fan switch on.
5. Verify that the cooling fan No.2 is operating and operation sound of A/C compressor magnetic clutch is heard.
6. Turn the A/C switch and fan switch off.

• If the cooling fan No.2 does not operate but operation sound of A/C compressor magnetic clutch is heard,

inspect for the following.
— Open circuit between ignition switch and cooling fan relay No.2
— Open circuit between battery and cooling fan relay No.2
— Open circuit between cooling fan relay No.2 and PCM terminal 4B
— Open circuit between cooling fan relay No.2 and cooling fan motor No.2 or fan motor GND
— Cooling fan relay No.2 is stuck open.
— Cooling fan motor No.2

• If both cooling fan No.2 and A/C compressor do not operate, inspect the following.

— TP PID
— A/C system

L3 engine models
Cooling fan system operation (at idle)

1. Connect WDS or equivalent to DLC-2.
2. Verify that ECT PID is below cooling fan operating temperature.
3. Verify that the A/C switch and fan switch are off.
4. Start the engine and let it at idle.
5. Verify that the cooling fan and condenser fan are not operating.

• If the cooling fan and condenser fan are operating low speed, inspect for following:

— Short to GND circuit between PCM terminal 4L and cooling fan relay No.2
— Cooling fan relay No.2 stuck in closed position

• If the cooling fan and condenser fan are operating high speed, inspect for following:

— DTC for ECT sensor (P0117, P0118)

Engine condition

Cooling fan

relay No.1

Cooling fan

relay No.2

Cooling fan

relay No.3

Cooling fan

relay No.4

Cooling fan

motor No.1

Cooling fan

motor No.2

Engine coolant temperature below
100

°C {212°F}

OFF

Engine coolant temperature above
100

°C {212°F} (until below 97°C

{208

°F})

OFF

Low speed

Engine coolant temperature above
108

°C {233°F} (until below 105°C

{208

°F})

High speed

A/C and fan
switches are
on.

Refrigerant pressure
switch (middle
pressure) is off.

OFF

Low speed

High speed

Refrigerant pressure
switch (middle
pressure) is on.

OFF

High speed

Low speed

ECT sensor malfunction

High speed

F–236

TROUBLESHOOTING

• If the cooling fan is not operating and condenser fan is operating, inspect for following:

— Short to GND circuit between PCM terminal 4F and transfer relay
— Transfer relay stuck ON position
— Short to GND circuit between PCM terminal 4B and cooling fan relay No.3
— Condenser fan relay stuck ON

6. Start the engine.
7. Verify that the cooling fan and condenser fan are operating low speed when ECT PID is above 100

°C {212°F}.

• If the cooling fans does not operate, perform the following:

1. Select FAN3 PID.
2. Operate cooling fan relay No.2 by sending ON command.
3. Inspect the operation sound is heard from cooling fan relay No.2.

— If the operation sound is heard, inspect wiring harnesses, connectors, transfer relay and cooling

and condenser fan motor.

— If the operation sound is not heard, inspect cooling fan relay No.2 and open circuit between PCM

terminal 4L and cooling fan relay No.2 wiring harness and connectors.

• Inspect the cooling fan is operating high speed, inspect the following:

— Short to GND circuit between PCM terminal 4F and cooling fan relay No.4/cooling fan relay No.1.
— Cooling fan relay stuck closed position

• If the condenser fan is operating high speed, inspect the following:

— Short to GND circuit between PCM terminal 4F and cooling fan relay No.4/cooling fan relay No.1
— cooling fan relay No.1 stuck ON position

8. Turn A/C switch and fan switch are on.
9. Verify that the ACCS PID is ON.

• If the ACCS PID is not ON, inspect for following:

— A/C switch
— Fan switch
— Refrigerant pressure switch
— Open circuit PCM 1AC related harnesses and connectors

10. Access the COLP PID.
11. Verify that the cooling fan is operating high speed an condenser fan is operating low speed, while the COLP

PID is ON.

• If the cooling fan and condenser fan are operating low speed, perform the following:

1. Select FAN1 PID.
2. Operate cooling fan relay No.4 and transfer relay by sending ON command.
3. Inspect the operation sound is heard from cooling fan relay No.4 and cooling fan relay No.1.

— 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.4 and cooling fan relay No.1, inspect

wiring harnesses and connectors.

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

— Cooling fan motor No.2 and related wiring harnesses and connectors

12. Verify that the cooling fan motor No.1 is operating low speed and the cooling fan motor No.1 is operating high

speed, while the COLP PID is OFF.

• If the cooling fan motor No.1 and cooling fan motor No.2 are operating low seed, perform the following:

1. Select FAN1 PID.
2. Operate cooling fan relay 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 coooling fan relay No.3 and open circuit wiring

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

TROUBLESHOOTING

F–237

L8, LF (Intensely hot area) engine models
Cooling fan system operation (at idle)

• If the cooling fan is operating low speed, inspect for following:

— Short to GND circuit between PCM terminal 4L and cooling fan relay No.2
— Cooling fan relay No.2 stuck in closed position

• If the cooling fans are operating high speed, inspect for following:

— DTC for ECT sensor (P0117, P0118)

• If the cooling fan motor No.1 is not operating and cooling fan motor No.2 is operating, inspect for following:

— Short to GND circuit between PCM terminal 4F and cooling fan relay No.1
— Cooling fan relay No.1 stuck ON
— Short to GND circuit between PCM terminal 4B and cooling fan relay No.3
— Cooling fan relay No.3 stuck ON

6. Start the engine.
7. Verify that the cooling fans are operating low speed when ECT PID is above 100

°C {212°F}.

• If the cooling fan motor No.1 does not operate, perform the following:

1. Select FAN3 PID.
2. Operate cooling fan relay No.2 by sending ON command.
3. Inspect the operation sound is heard from cooling fan relay No.2.

— If the operation sound is heard, inspect wiring harnesses, connectors and cooling fan motor No.1.
— If the operation sound is not heard, inspect cooling fan relay No.2 and open circuit between PCM

terminal 4L and cooling fan relay No.2 wiring harness and connectors.

• Inspect the cooling fan is operating high speed, inspect the following:

— Short to GND circuit between PCM terminal 4F and cooling fan relay No.1/cooling fan relay No.4.

8. Turn A/C switch and fan switch are on.
9. Verify that the ACCS PID is ON.

• If the ACCS PID is not ON, inspect for following:

— A/C switch
— Fan switch
— Refrigerant pressure switch
— Open circuit PCM 1AC related harnesses and connectors

10. Access the COLP PID.
11. Verify that the cooling fan motor No.1 is operating high speed and cooling fan motor No.2 is operating low

speed, while the COLP PID is ON.

• If the cooling fan motor No.1 does not operate high speed, perform the following:

1. Select FAN1 PID.
2. Operate cooling fan relay No.1 and cooling fan relay No.4 by sending ON command.

Engine condition

Cooling fan

relay No.2

Cooling fan

relay No.4

Cooling fan

relay No.1

Cooling fan

relay No.3

Cooling fan

motor No.1

Cooling fan

motor No.2

Engine coolant temperature below
100

°C {212°F}

OFF

Engine coolant temperature above
100

°C {212°F} (until below 97°C

{208

°F})

OFF

Low speed

OFF

Engine coolant temperature above
108

°C {233°F} (until below 105°C

{208

°F})

High speed

A/C and fan
switches are
on.

Refrigerant pressure
switch (middle
pressure) is off.

OFF

Low speed

OFF

Refrigerant pressure
switch (middle
pressure) is on.

OFF

High speed

Low speed

ECT sensor malfunction

High speed

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