air INFINITI FX35 2004 Service Manual

ATC-80
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 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
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.
*7AT C - 4 2 , "SYMPTOM TABLE".*8ATC-104, "Ambient Sensor Circuit".*9ATC-107, "In-vehicle Sensor Cir-
cuit".
*10AT C - 11 0 , "
Sunload Sensor Circuit".*11EC-185, "DTC P0117, P0118 ECT
SENSOR" (VQ35DE) or EC-842,
"DTC P0117, P0118 ECT SEN-
SOR" (VK45DE).
RJIA1995E

ATC-82
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 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 (L/W) 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-83,
"FUSE BLOCK - JUNCTION BOX (J/B)" .

If OK, check for open circuit in wiring harness. Repair or replace if necessary.

If NG, replace fuse and check wiring harness for short circuit. Repair or replace if necessary.
2. CHECK BLOWER MOTOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between blower motor harness connector M78
terminal 3 (B) 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 (G) and unified meter and A/C amp. harness connec-
tor M57 terminal 53 (G).
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
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. Vary the fan speed between Lo and Hi and confirm the duty
ratios between blower motor harness connector M78 terminal 21 – Ground : Battery voltage
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3 – Ground : Continuity should exist.
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2 – 53 : Continuity should exist.
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TROUBLE DIAGNOSIS
ATC-83
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Revision: 2004 November 2004 FX35/FX45
(G) and ground using an oscilloscope. Usual No. 2 terminal drive signal duty ratios are shown in the table
below.
OK or NG
OK >> GO TO 5.
NG >> Replace unified meter and A/C amp.
5. CHECK BLOWER MOTOR DRIVE SIGNAL
If the fan air flow does not change, usual No. 2 (G) terminal drive signal duty ratios are shown in the table
above.
OK or NG
OK >> Replace blower motor.
NG >> INSPECTION END
COMPONENT INSPECTION
Blower Motor
Confirm smooth rotation of the blower motor.

Ensure that there are no foreign particles inside the blower unit.
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ATC-85
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AT C
Revision: 2004 November 2004 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).
DIAGNOSTIC PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
RHA094GB
SJIA0267E
RJIA2003E

ATC-86
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
1. CHECK INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to AT C - 5 4 , "
FUNCTION CONFIRMATION PROCEDURE" ,
see No. 9 and 11.
OK or NG
OK >> GO TO 2.
NG >>

Malfunctioning ambient sensor: Refer to ATC-104, "Ambient Sensor Circuit" .

Malfunctioning intake sensor: Refer to AT C - 11 3 , "Intake Sensor Circuit" .
2. PERFORM AUTO ACTIVE TEST
Refer to PG-24, "
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), 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 (magnet
clutch) connector.
3. Check continuity between IPDM E/R harness connector E8 ter-
minal 33 (L) and compressor harness connector F2 terminal 1
(L).
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 >> Replace IPDM E/R.
NG >> Replace magnet clutch. Refer to ATC-143, "
Removal
and Installation of Compressor Clutch" .
33 – 1 : Continuity should exist.
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TROUBLE DIAGNOSIS
ATC-87
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Revision: 2004 November 2004 FX35/FX45
5. CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to AT C - 4 0 , "
CONSULT-II" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
6. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect BCM connector and unified meter and A/C amp.
connector.
3. Check continuity between BCM harness connector M3 terminal
27 (R/Y) and unified meter and A/C amp. harness connector
M57 terminal 42 (R/Y).
OK or NG
OK >> GO TO 7.
NG >> Repair harness or connector.
7. CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (COMPRESSOR ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp.
connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness
connector M57 terminal 42 (R/Y) and ground.
OK or NG
OK >> GO TO 8.
NG-1 >> If the voltage is approx. 5V when A/C switch is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0V when A/C switch is OFF: Replace BCM.A/C SW ON : AIR COND SW ON
A/C SW OFF : AIR COND SW OFF
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27 – 42 : Continuity should exist.
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Terminals
Condition Voltage (+)
(−) Unified meter
and A/C amp.
connectorTerminal No.
(wire color)
M57 42 (R/Y) GroundA/C switch: ON Approx. 0V
A/C switch: OFF Approx. 5V
RJIA2007E

ATC-88
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
8. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start the engine.
2. Check voltage of refrigerant pressure sensor. Refer to EC-125, "
CONSULT-II Reference Value in Data
Monitor" (VQ35DE) or EC-775, "CONSULT-II Reference Value in Data Monitor" (VK45DE).
WITHOUT CONSULT-II
1. Start the engine.
2. Check voltage between ECM harness connector F101 terminal
70 (L/R) and ground.
OK or NG
OK >>
WITH CONSULT-II
GO TO 9.

WITHOUT CONSULT-II
GO TO 10.
NG >> Refer to EC-609, "
REFRIGERANT PRESSURE SENSOR" (VQ35DE) or EC-1287, "REFRIGER-
ANT PRESSURE SENSOR" (VK45DE).
9. CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to AT C - 4 0 , "
CONSULT-II" .
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect BCM connector and unified meter and A/C amp.
connector.
3. Check continuity between BCM harness connector M3 terminal
28 (BR/Y) and unified meter and A/C amp. harness connector
M57 terminal 57 (BR/Y).
OK or NG
OK >> GO TO 11.
NG >> Repair harness or connector.
Te r m i n a l s
Condition Voltage (+)
(−)
ECM con-
nectorTerminal No.
(wire color)
F101 70 (L/R) Ground A/C switch: ON Approx. 1 - 4V
PBIB1188E
FAN SW ON :FAN ON SIG ON
FAN SW OFF :FAN ON SIG OFF
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28 – 57 : Continuity should exist.
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TROUBLE DIAGNOSIS
ATC-89
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Revision: 2004 November 2004 FX35/FX45
11 . CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (FAN ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp.
connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness
connector M57 terminal 57 (BR/Y) and ground.
OK or NG
OK >> GO TO 12.
NG-1 >> If the voltage is approx. 5V when blower motor is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0V when blower motor is OFF: Replace BCM. Refer to BCS-15, "
Removal
and Installation of BCM" .
12. CHECK CAN COMMUNICATION
Check CAN communication. Refer to BCS-14, "
CAN Communication Inspection Using CONSULT-II (Self-
Diagnosis)" .

BCM – ECM

ECM – IPDM E/R

ECM – Unified meter and A/C amp.
OK or NG
OK >> INSPECTION END
NG >> Repair or replace malfunctioning part(s).
Terminals
Condition Voltage (+)
(-) Unified meter
and A/C amp.
connectorTerminal No.
(wire color)
M57 57 (BR/Y) GroundA/C switch: ON
(Blower motor
operates)Approx. 0V
OFF switch: ON
(A/C system:
OFF)Approx. 5V
RJIA2010E

ATC-92
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
*1ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6.*2ATC-73, "
Air Mix Door Motor Circuit".*3ATC-95, "Test Reading".
*4ATC-59, "
AUXILIARY MECHA-
NISM: TEMPERATURE SETTING
TRIMMER".*5ATC-54, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.*6ATC-66, "
LAN System Circuit".
*7ATC-79, "
Blower Motor Circuit".*8ATC-84, "Magnet Clutch Circuit".*9ATC-93, "PERFORMANCE TEST
DIAGNOSIS".
*10ATC-61, "
Operational Check".*11AT C - 5 , "CONTAMINATED REFRIG-
ERANT".*12EM-15, "
Checking Drive Belts"
(VQ35DE) or EM-169, "
Checking
Drive Belts" (VK45DE).
*13EC-472, "
SYSTEM DESCRIPTION"
(VQ35DE) or EC-1142, "
SYSTEM
DESCRIPTION" (VK45DE).

TROUBLE DIAGNOSIS
ATC-93
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Revision: 2004 November 2004 FX35/FX45
PERFORMANCE TEST DIAGNOSIS
*1AT C - 9 5 , "PERFORMANCE
CHART".*2ATC-95, "
PERFORMANCE
CHART".*3AT C - 9 6 , "
TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE".
*4AT C - 7 3 , "
Air Mix Door Motor Circuit".
RJIA1601E