INFINITI FX35 2007 Service Manual

TROUBLE DIAGNOSIS ATC-75
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Revision: 2006 July 2007 FX35/FX45
SYSTEM DESCRIPTION
Component Parts
Intake door control system components are:

Unified meter and A/C amp.

Intake door motor (LCU)

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
The intake door control determines intake door position based on the ambient temperature, the intake air tem-
perature and the in-vehicle temperature. When the DEF, or OFF switches are pressed or A/C switch is OFF,
the unified meter and A/C amp. sets the intake door at the FRE position.
Intake Door Control Specification
SJIA1588E
RJIA1787E

ATC-76
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
COMPONENT DESCRIPTION
Intake Door Motor
The intake door motor is attached to the blower unit. It rotates so that
air is drawn from inlets set by the unified meter and A/C amp. Motor
rotation is conveyed to a lever which activates the intake door.
DIAGNOSIS PROCEDURE FOR INTAKE DOOR MOTOR
SYMPTOM: Intake door motor does not operate normally.
Perform diagnosis procedure. Refer to AT C - 6 4 , "
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
RJIA0897E

TROUBLE DIAGNOSIS ATC-77
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Revision: 2006 July 2007 FX35/FX45
Blower Motor CircuitNJS000E8
SYMPTOM: Blower motor operation is malfunctioning.
INSPECTION FLOW
*1ATC-60, "Operational Check"*2AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4. *3
ATC-53, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 6.
*4 ATC-103, "
Ambient Sensor Circuit"*5ATC-106, "In-vehicle Sensor Circuit"*6ATC-109, "Sunload Sensor Circuit"
*7 ATC-112, "Intake Sensor Circuit"*8AT C - 4 1 , "SYMPTOM TABLE"*9ATC-53, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*10 ATC-79, "
DIAGNOSIS PROCE-
DURE FOR BLOWER MOTOR"
*11EC-209, "DTC P0117, P0118 ECT
SENSOR" (VQ35DE) or EC-880,
"DTC P0117, P0118 ECT SEN-
SOR" (VK45DE)
SJIA1808E

ATC-78
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
SYSTEM DESCRIPTION
Component Parts
Fan speed control system components are:

Unified meter and A/C amp.

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calculated by the unified meter and A/C amp. based on the
input from the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.
When the air flow is increased, the duty ratio of the blower fan motor’s drive signal is changed at 8%/sec. to
prevent a sudden increase in air flow.
In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low
water temperature starting control and high passenger compartment temperature starting control are avail-
able.
RJIA1995E

TROUBLE DIAGNOSIS ATC-79
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Revision: 2006 July 2007 FX35/FX45
Starting Fan Speed Control
Start up from COLD SOAK Condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 56 °C (133 °F), the blower will not
operate for a short period of time (up to 150 seconds). The exact start delay time varies depending on the
ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described
above. After this delay, the blower will operate at low speed until the engine coolant temperature rises above
56 °C (133 °F), and then the blower speed will increase to the objective speed.
Start up from usual or HOT SOAK Condition (Automatic mode)
The blower will begin operation momentarily after the AUTO switch is pressed. The blower speed will gradu-
ally rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
Blower Speed Compensation
Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. During conditions of low or no sunload, the blower
speed is at duty ratio 25%. During high sunload conditions, the unified meter and A/C amp. raise the blower
speed (duty ratio 49%).
Fan Speed Control Specification
COMPONENT DESCRIPTION
Brush-Less Motor
The blower motor utilizes a brush-less motor with a rotating magnet.
Quietness is improved over previous motors where the brush was
the point of contact and the coil rotated.
DIAGNOSIS PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning.
RJIA1996E
ZHA152H
SJIA0266E

ATC-80
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
1. CHECK POWER SUPPLY FOR BLOWER MOTOR
1. Disconnect blower motor connector.
2. Turn ignition switch ON.
3. Check voltage between blower motor harness connector M78 terminal 1 and ground.
OK or NG
OK >> GO TO 2.
NG >> Check power supply circuit and 15A fuses [Nos. 10 and 11, located in the fuse block (J/B)]. Refer to PG-80,
"FUSE BLOCK - JUNCTION BOX (J/B)" .

If fuses are OK, check harness for open circuit. Repair or replace if necessary.

If fuses are NG, check harness for short circuit and replace fuse.
2. CHECK BLOWER MOTOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between blower motor harness connector M78 terminal 3 and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK CIRCUIT CONTINUITY BETWEEN BLOWER MOTOR AND UNIFIED METER AND A/C AMP.
1. Disconnect unified meter and A/C amp. connector.
2. Check continuity between blower motor harness connector M78 terminal 2 and unified meter and A/C amp. harness connector
M57 terminal 53.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector. 1 – Ground : Battery voltage
RJIA1997E
3 – Ground : Continuity should exist.
RJIA1998E
2 – 53 : Continuity should exist.
RJIA1999E

TROUBLE DIAGNOSIS ATC-81
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Revision: 2006 July 2007 FX35/FX45
4. CHECK UNIFIED METER AND A/C AMP. OUTPUT SIGNAL
1. Reconnect blower motor connector and unified meter and A/C amp. connector.
2. Turn ignition switch ON.
3. Change the fan speed from Lo to Hi, and check the duty ratios between blower motor harness connector M78 terminal 2 and ground using an oscilloscope. Normal terminal 2 drive signal duty ratios are shown in
the table below.
OK or NG
OK >> Replace blower motor after confirming the fan air flow does not change.
NG >> Replace unified meter and A/C amp.
COMPONENT INSPECTION
Blower Motor
Confirm smooth rotation of the blower motor.

Ensure that there are no foreign particles inside the blower unit.
RJIA2000E
SJIA1802E
RJIA0905E

ATC-82
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
Magnet Clutch CircuitNJS000E9
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1ATC-112, "Intake Sensor Circuit"*2 ATC-103, "Ambient Sensor Circuit"*3AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*4 ATC-83, "
DIAGNOSIS PROCE-
DURE FOR MAGNET CLUTCH"
*5 ATC-95, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"
*6AT C - 6 0 , "Operational Check"
*7ATC-53, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *8
ATC-41, "
SYMPTOM TABLE"
SJIA1590E

TROUBLE DIAGNOSIS ATC-83
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Revision: 2006 July 2007 FX35/FX45
SYSTEM DESCRIPTION
Unified meter and A/C amp. controls compressor operation by ambient temperature, intake air temperature
and signal from ECM.
Low Temperature Protection Control
Unified meter and A/C amp. will turn the compressor ON or OFF as determined by a signal detected by ambi-
ent sensor and intake sensor.
When ambient temperature is higher than −2 °C (28 °F), the compres-
sor turns ON. The compressor turns OFF when ambient temperature
is lower than −5 °C (23 °F).
When intake air temperature is higher than 1 °C (34 °F), the compres-
sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than −5°C (23 °F).
DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
RHA094GB
SJIA0267E
SJIA1608E

ATC-84
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
1. CHECK AMBIENT SENSOR AND INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to AT C - 5 3 , "
FUNCTION CONFIRMATION PROCEDURE" ,
see No. 9 and 11.
OK or NG
OK >> GO TO 2.
NG >>

Malfunctioning ambient sensor: Refer to ATC-103, "Ambient Sensor Circuit" .

Malfunctioning intake sensor: Refer to AT C - 11 2 , "Intake Sensor Circuit" .
2. PERFORM AUTO ACTIVE TEST
Refer to PG-21, "
Auto Active Test" .
Does the magnet clutch operate?
YES >>
WITH CONSULT-II: GO TO 5

WITHOUT CONSULT-II: GO TO 6.
NO >> Check 10A fuse (No. 79, located in IPDM E/R). Refer to PG-25, "
IPDM E/R Terminal Arrange-
ment" , and GO TO 3.
3. CHECK CIRCUIT CONTINUITY BETWEEN IPDM E/R AND COMPRESSOR
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R connector and compressor connector.
3. Check continuity between IPDM E/R harness connector E8 ter- minal 33 and compressor harness connector F2 terminal 1.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK MAGNET CLUTCH CIRCUIT
Check for operation sound when applying battery voltage direct cur-
rent to terminal.
OK or NG
OK >> 1. Replace IPDM E/R. 2. Go to self-diagnosis procedure AT C - 5 3 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-4. Confirm that magnet clutch opera-
tion normal.
NG >> 1. Replace magnet clutch. 2. Go to self-diagnosis procedure AT C - 5 3 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-4. Confirm that magnet clutch operation normal.
33 – 1 : Continuity should exist.
RJIA2004E
RJIA2005E