Infiniti Q45. Manual - part 527

REFRIGERANT PRESSURE SENSOR

EC-747

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EC

2. 

CHECK GROUND CONNECTIONS

1.

Turn A/C switch and blower switch OFF.

2.

Stop engine.

3.

Turn ignition switch OFF.

4.

Loosen and retighten three ground screws on the body.
Refer to 

EC-154, "Ground Inspection"

 .

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace ground connections.

3. 

CHECK REFRIGERANT PRESSURE SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect refrigerant pressure sensor harness connector.

2.

Turn ignition switch ON.

3.

Check voltage between refrigerant pressure sensor terminal 1
and ground with CONSULT-II or tester.

OK or NG

OK

>> GO TO 5.

NG

>> GO TO 4.

4. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors E33, F33

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Harness for open or short between ECM and refrigerant pressure sensor

>> Repair open circuit or short to ground or short to power in harness or connectors.

PBIB2417E

PBIB0037E

Voltage: Approximately 5V

PBIB0188E

EC-748

REFRIGERANT PRESSURE SENSOR

5. 

CHECK REFRIGERANT PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between refrigerant pressure sensor terminal 3 and ECM terminal 67.
Refer to Wiring Diagram.

4.

Also check harness for short to ground or short to power.

OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

6. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors E33, F33

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Harness for open or short between ECM and refrigerant pressure sensor

>> Repair open circuit or short to ground or short to power in harness or connectors.

7. 

CHECK REFRIGERANT PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check harness continuity between ECM terminal 70 and refrigerant pressure sensor terminal 2.
Refer to Wiring Diagram.

2.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 9.

NG

>> GO TO 8.

8. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors E33, F33

●

Harness for open or short between ECM and refrigerant pressure sensor

>> Repair open circuit or short to ground or short to power in harness or connectors.

9. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

OK or NG

OK

>> Replace refrigerant pressure sensor.

NG

>> Repair or replace. 

Removal and Installation

NBS0027J

REFRIGERANT PRESSURE SENSOR

Refer to 

ATC-156, "Removal and Installation of Refrigerant Pressure Sensor"

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Continuity should exist.

Continuity should exist.

VARIABLE INDUCTION AIR CONTROL SYSTEM (VIAS)

EC-749

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EC

VARIABLE INDUCTION AIR CONTROL SYSTEM (VIAS)

PFP:14956

Description

NBS0026T

SYSTEM DESCRIPTION

*: ECM determines the start signal status by the signals of engine speed and battery voltage.

When the engine is running at low or medium speed, the power valve is fully closed. Under this condition, the
effective suction port length is equivalent to the total length of the intake manifold collector's suction port
including the intake valve. This long suction port provides increased air intake which results in improved suc-
tion efficiency and higher torque generation.
The surge tank and one-way valve are provided. When engine is running at high speed, the ECM sends the
signal to the VIAS control solenoid valve. This signal introduces the intake manifold vacuum into the power
valve actuator and therefore opens the power valve to two suction passages together in the collector.
Under this condition, the effective port length is equivalent to the length of the suction port provided indepen-
dently for each cylinder. This shortened port length results in enhanced engine output with reduced suction
resistance under high speeds.
The power valve is always open regardless of the engine speed when selector lever position is in N or P.

Sensor

Input Signal to ECM

ECM function

Actuator

Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)

Engine speed*

VIAS control

VIAS control solenoid valve

Mass air flow sensor

Amount of intake air

Engine coolant temperature sensor

Engine coolant temperature

Throttle position sensor

Throttle position

Accelerator pedal position sensor

Accelerator pedal position

Battery

Battery voltage*

PBIB1876E

EC-750

VARIABLE INDUCTION AIR CONTROL SYSTEM (VIAS)

COMPONENT DESCRIPTION
Power Valve

The power valve is installed in intake manifold collector and used to
control the suction passage of the variable induction air control sys-
tem. It is set in the fully closed or fully opened position by the power
valve actuator operated by the vacuum stored in the surge tank. The
vacuum in the surge tank is controlled by the VIAS control solenoid
valve.

VIAS Control Solenoid Valve

The VIAS control solenoid valve cuts the intake manifold vacuum
signal for power valve control. It responds to ON/OFF signals from
the ECM. When the solenoid is OFF, the vacuum signal from the
intake manifold is cut. When the ECM sends an ON signal the coil
pulls the plunger downward and feeds the vacuum signal to the
power valve actuator.

CONSULT-II Reference Value in Data Monitor Mode

NBS0026U

Specification data are reference values.

PBIB2421E

PBIB2421E

MONITOR ITEM

CONDITION

SPECIFICATION

VIAS S/V

●

Selector lever: P or N

ON

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Engine speed: More than 5,000 rpm

●

Selector lever: Except P or N

●

Engine speed: Less than 5,000 rpm

OFF