Infiniti FX35, FX50 (S51). Manual - part 738

POSITIVE CRANKCASE VENTILATION

EC-493

< DTC/CIRCUIT DIAGNOSIS >

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With engine running at idle, remove PCV valve from rocker cover. A
properly working valve makes a hissing noise as air passes through
it. A strong vacuum should be felt immediately when a finger is
placed over valve inlet.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace PCV valve.

PBIB1589E

EC-494

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

REFRIGERANT PRESSURE SENSOR

REFRIGERANT PRESSURE SENSOR

Description

INFOID:0000000005237113

The refrigerant pressure sensor is installed at the condenser of the air conditioner system. The sensor uses an
electrostatic volume pressure transducer to convert refrigerant pressure to voltage. The voltage signal is sent
to ECM, and ECM controls cooling fan system.

Component Function Check

INFOID:0000000005237114

1.

CHECK REFRIGERANT PRESSURE SENSOR FUNCTION

1.

Start engine and warm it up to normal operating temperature.

2.

Turn A/C switch and blower fan switch ON.

3.

Check the voltage between ECM harness connector terminals under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-494, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005237115

1.

CHECK GROUND CONNECTION

1.

Turn A/C switch and blower fan switch OFF.

2.

Turn ignition switch OFF.

3.

Check ground connection M95. Refer to Ground Inspection in 

GI-39, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK REFRIGERANT PRESSURE SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect refrigerant pressure sensor harness connector.

2.

Turn ignition switch ON.

3.

Check the voltage between refrigerant pressure sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 3.

PBIB2657E

ECM

Voltage (V)

Connector

+

–

Terminal

Terminal

M107

105

(Refrigerant pressure sensor signal)

116

1.0 - 4.0

Refrigerant pressure sensor

Ground

Voltage (V)

Connector

Terminal

E77

3

Ground

Approx. 5

REFRIGERANT PRESSURE SENSOR

EC-495

< DTC/CIRCUIT DIAGNOSIS >

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3.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors M6, E106
• Harness for open or short between ECM and refrigerant pressure sensor

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

4.

CHECK REFRIGERANT PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between refrigerant pressure sensor harness connector and ECM harness connec-
tor.

4.

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

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 5.

5.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors M6, E106
• Harness for open or short between ECM and refrigerant pressure sensor

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

6.

CHECK REFRIGERANT PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check the continuity between refrigerant pressure sensor harness connector and ECM harness connec-
tor.

2.

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

Is the inspection result normal?

YES

>> GO TO 8.

NO

>> GO TO 7.

7.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors M6, E106
• Harness for open or short between ECM and refrigerant pressure sensor

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

8.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-36, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace refrigerant pressure sensor.

NO

>> Repair or replace malfunctioning part. 

Refrigerant pressure sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E77

1

M107

116

Existed

Refrigerant pressure sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E77

2

M107

105

Existed

EC-496

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

SNOW MODE SWITCH

SNOW MODE SWITCH

Description

INFOID:0000000005237116

The snow mode switch signal is sent to the “unified meter and A/C amp.” from the snow mode switch. The
“unified meter and A/C amp.” then sends the signal to the ECM by CAN communication line.
The snow mode is used for driving or starting the vehicle on snowy roads or slippery areas. If the snow mode
is activated, the vehicle speed will not accelerator as quickly as normal to avoid vehicle slip. In other words,
ECM controls rapid engine torque change by controlling the electric throttle control actuator operating speed.

Component Function Check

INFOID:0000000005237117

1.

CHECK SNOW MODE SWITCH FUNCTION

1.

Turn ignition switch ON.

2.

Select “SNOW MODE SW” in “DATA MONITOR” mode with CONSULT-III.

3.

Check “SNOW MODE SW” indication under the following conditions.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Go to 

EC-496, "Diagnosis Procedure"

.

2.

CHECK SNOW MODE INDICATOR FUNCTION

1.

Turn ignition switch ON.

2.

Check the snow mode indicator in the snow mode switch under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-496, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005237118

1.

CHECK SNOW MODE SWITCH OVERALL FUNCTION

Confirm the malfunctioning circuit (snow mode switch or snow mode indicator). Refer to 

EC-496, "Component

Function Check"

.

Which circuit is related to the incident?

Snow mode switch>>GO TO 2.
Snow mode indicator>>GO TO 6.

2.

CHECK DTC WITH “UNIFIED METER AND A/C AMP.”

Refer to 

MWI-45, "CONSULT-III Function (METER/M&A)"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Go to 

MWI-4, "Work flow"

.

3.

CHECK SNOW MODE SWITCH POWER SUPPLY CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect snow mode switch harness connector.

3.

Turn ignition switch ON.

4.

Check the voltage between snow mode switch harness connector and ground.

Monitor item

Condition

Indication

SNOW MODE SW

Snow mode switch

ON

ON

OFF

OFF

Condition

Snow mode indicator

Snow mode switch

ON

ON

OFF

OFF