Mazda X-5. Manual — part 40

CONTROL SYSTEM

01–40–33

01–40

A/C CUT-OFF CONTROL OUTLINE [LF]

E5U014000000N43

• Through energization and non-energization to the A/C relay (magnetic clutch) according to engine operation

conditions, acceleration performance and engine reliability have been improved.

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A/C CUT-OFF CONTROL BLOCK DIAGRAM [LF]

E5U014000000N44

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A/C CUT-OFF CONTROL OPERATION [LF]

E5U014000000N45

• The PCM stops energization to the A/C relay when any of the following conditions are met:

A/C cut-off control operation conditions

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TR SWITCH (AT)

ECT SENSOR

CKP SENSOR

NEUTRAL SWITCH (MT)

CPP SWITCH (MT)

A/C RELAY

PCM

TP SENSOR NO.1, NO.2

APP SENSOR NO.1, NO.2

A/C AMPLIFER

REFRIGERANT PRESSURE

SWITCH (HIGH, LOW)

E5U140ZT5009

Operation condition

A/C relay non-energization period

Purpose

At engine start

Approx. 4 s

Improved startability

At drive-away

Approx. 3 s

Improved drive-away
performance

During acceleration (throttle valve opening angle 50%
or more)

Approx. 5 s

Improved acceleration
performance

When the engine coolant temperature is 113

°C {235

°F}

Repeatedly turns on and off every 10 s

until the engine coolant temperature is

less than approx. 110

°C {230 °F}

Improved engine reliability

When the engine coolant temperature is 118

°C {245

°F} or more

Until the engine coolant temperature

decreases to less than approx. 114

°C

{237

°F}

Improved engine reliability

At high engine speed (engine speed 6,600 rpm or
more)

Approx. 1 s

Improved engine speed
stability

CONTROL SYSTEM

01–40–34

ELECTRICAL FAN CONTROL OUTLINE [LF]

E5U014000000N46

• Through cooling of the radiator and condenser by operation of the cooling fan according to vehicle conditions,

engine reliability and cooling performance have been improved.

• The electrical fan control includes the regular-driving cooling function and the after-cooling function.

• The regular-driving cooling function operates according to the engine conditions during the engine operation.

• The after-cooling function operates when the vehicle has stopped at high engine temperature (ignition switch

off).

• After the ignition switch is turned off, a main relay on request is sent to operate the after-cooling function. (See

01–40–11 MAIN RELAY CONTROL OPERATION [LF].)

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ELECTRICAL FAN CONTROL BLOCK DIAGRAM [LF]

E5U014000000N47

• The PCM determines the engine operation conditions based on input signals from the sensors, and sends a

signal to the cooling fan relay No.1, No.2, No.3.

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ELECTRICAL FAN CONTROL OPERATION [LF]

E5U014000000N48

• When the operation conditions are met for each function, the PCM sends an operation signal to cooling fan

relay No.1 or No.2/No.3 to operate the cooling fan motors.

• The rotation speed of the cooling fan motor is switched between three levels according to a combination of the

cooling fan relays.

• The cooling fan motor operation switches in the order of stop, low speed, middle speed, and high speed, taking

3 s for each operation while regular-driving cooling.

ECT SENSOR

VEHICLE SPEED SIGNAL

IGNITION SWITCH

COOLING FAN RELAY NO.2

PCM

TP SENSOR NO.1, NO.2

COOLING FAN RELAY NO.3

COOLING FAN RELAY NO.1

IAT SENSOR

REFRIGERANT PRESSURE

SWITCH (MIDDLE)

A/C AMPLIFER

REFRIGERANT PRESSURE

SWITCH (HIGH, LOW)

E5U140ZT5010

CONTROL SYSTEM

01–40–35

01–40

Operation Conditions

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Function

Operation condition

Cooling fan

motor rotation

speed

Cooling fan relay

ECT

A/C

amplifier

(A/C switch)

Refrigerant

pressure

switch

(high, low)

Vehicle speed

No.1

No.2

No.3

Regular-
driving cooling

Less than 100

°C

{212

°F}

OFF

—

Stop

OFF

ON

OFF

More than 70

km/h {44 mph}

45 —70 km/h

{28—43 mph}

Low

ON

OFF

OFF

Less than 45

km/h {27 mph}

Middle

ON

OFF

ON

ON

—

High

ON

100—108

°C

{213—226.4

°F}

OFF

—

Middle

ON

OFF

ON

ON

High

ON

More than 108

°C

{227

°F}

—

After-cooling

• When all the following conditions are met:

— Ignition switch: OFF

— Estimated maximum engine coolant temperature is high after

engine stop

Low

ON

OFF

OFF

• When all the following conditions are met:

— Estimated maximum engine coolant temperature is the

specified value or more even when operating at low rotation
speed.

Middle

ON

OFF

ON

COOLING
FAN RELAY
NO.1

COOLING
FAN RELAY
NO.3

COOLING
FAN RELAY
NO.2

TO PCM

TO PCM

TO PCM

B+

E5U140ZN5855

CONTROL SYSTEM

01–40–36

STARTER CUT-OFF CONTROL OUTLINE [LF]

E5U014000000N49

• Theft deterrence has been improved by controlling energization to the starter relay according to an engine stop

request signal from the immobilizer system.

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STARTER CUT-OFF CONTROL BLOCK DIAGRAM [LF]

E5U014000000N50

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STARTER CUT-OFF CONTROL OPERATION [LF]

E5U014000000N51

• The PCM stops energization of the starter relay according to an engine stop request from the immobilizer

system.
When receiving engine stop request signal

— The PCM does not establish a ground to the starter circuit. Therefore, the starter motor does not rotate

because there is no energization of the starter relay even if the ignition switch is turned to the START
position, and the engine does not start.

When not receiving engine stop request signal

— The PCM establishes a ground to the starter circuit. Therefore, when the ignition switch is turned to the

START position, the starter relay is energized and the starter motor rotates. As a result, the engine starts
normally.

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INSTRUMENT CLUSTER

(IMMOBILIZER RELATED

INFORMATION)

STARTER RELAY

PCM

E5U140ZW5403

PCM

M

WHEN NOT RECEIVING ENGINE
STOP REQUEST SIGNAL

WHEN ENGINE STOP REQUEST
SIGNAL IS RECEIVED

IGNITION
SWITCH

START
SIGNAL

STARTER
RELAY

STARTER

AT

TR SWITCH

STARTER
SWITCH

MT

IG 1

B+

PCM

M

IGNITION

SWITCH

START
SIGNAL

STARTER
RELAY

STARTER

AT

TR SWITCH

STARTER
SWITCH

MT

IG 1

B+

E5U140ZT5200