INFINITI M35 2007 Factory Service Manual

ATC-90
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
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.
SJIA0942E
ZHA152H
RJIA4071E

TROUBLE DIAGNOSIS
ATC-91
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Revision: 2007 April2007 M35/M45
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 M91
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-114,
"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 M91
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 M91
terminal 2 and unified meter and A/C amp. harness connector
M64 terminal 38.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.1 – Ground : Battery voltage
RJIA1997E
3 – Ground : Continuity should exist.
RJIA4072E
2 – 38 : Continuity should exist.
RJIA4073E

ATC-92
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
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. Set MODE switch to VENT position.
4. Change the fan speed from Lo to Hi, and check the duty ratios
between blower motor harness connector M91 terminal 2 and
ground by 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.
RJIA4074E
RJIA4075E
RJIA4076E

TROUBLE DIAGNOSIS
ATC-93
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AT C
Revision: 2007 April2007 M35/M45
Magnet Clutch CircuitNJS000GU
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1ATC-121, "Intake Sensor Circuit"*2ATC-112, "Ambient Sensor Circuit"*3AT C - 5 7 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*4AT C - 9 4 , "
DIAGNOSIS PROCE-
DURE FOR MAGNET CLUTCH"
*5ATC-104, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"
*6AT C - 6 5 , "Operational Check"
*7AT C - 5 7 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 2 to 6.*8ATC-41, "
SYMPTOM TABLE"
RJIA4077E

ATC-94
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
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 compressor ON or OFF as determined by a signal detected by ambient
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
RJIA4078E

TROUBLE DIAGNOSIS
ATC-95
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Revision: 2007 April2007 M35/M45
1. CHECK AMBIENT SENSOR AND INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to AT C - 5 7 , "
FUNCTION CONFIRMATION PROCEDURE" ,
see No. 9 and 11.
OK or NG
OK >> GO TO 2.
NG >>

Malfunctioning ambient sensor: Refer to AT C - 11 2 , "Ambient Sensor Circuit" .

Malfunctioning intake sensor: Refer to ATC-121, "Intake Sensor Circuit" .
2. PERFORM AUTO ACTIVE TEST
Refer to PG-23, "
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-28, "
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 34 and compressor harness connector F24 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 7 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-4. Confirm that magnet clutch opera-
tion normal.
NG >> 1. Replace compressor.
2. Go to self-diagnosis procedure AT C - 5 7 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-4. Confirm that magnet clutch operation normal.
34 – 1 : Continuity should exist.
RJIA4079E
RJIA2005E

ATC-96
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
5. CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to AT C - 4 0 , "
CONSULT-II
Function (ECM)" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
6. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start the engine.
2. Check voltage of refrigerant pressure sensor. Refer to EC-138, "
CONSULT-II Reference Value in Data
Monitor" (VQ35DE) or EC-841, "CONSULT-II Reference Value in Data Monitor" (VK45DE).
WITHOUT CONSULT-II
1. Start the engine.
2. Check voltage between ECM harness connector F108 terminal
70 and ground.
OK or NG
OK >>
WITH CONSULT-II: GO TO 7.

WITHOUT CONSULT-II: Repair harness or connector.
NG >> Refer to EC-704, "
REFRIGERANT PRESSURE SENSOR" (VQ35DE) or EC-1424, "REFRIGER-
ANT PRESSURE SENSOR" (VK45DE).
7. CHECK ECM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to AT C - 4 0 , "
CONSULT-II Function
(ECM)" .
OK or NG
OK >> GO TO 8.
NG >> Repair harness or connector.A/C SW ON : AIR COND SIG ON
A/C SW OFF : AIR COND SIG OFF
RJIA3646E
Terminals
Condition Voltage (+)
(−)
ECM
connectorTerminal
No.
F108 70 GroundA/C switch: ON
(Blower motor operates.)Approx. 1.0 -
4.0 V
PBIB1188E
FAN SW ON : HEATER FAN SW ON
FAN SW OFF : HEATER FAN SW OFF
RJIA3646E

TROUBLE DIAGNOSIS
ATC-97
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AT C
Revision: 2007 April2007 M35/M45
8. CHECK CAN COMMUNICATION
Check CAN communication. Refer to EC-161, "
DTC U1000, U1001 CAN COMMUNICATION LINE"
(VQ35DE) or EC-865, "DTC U1000, U1001 CAN COMMUNICATION LINE" (VK45DE).

ECM – IPDM E/R

ECM – Unified meter and A/C amp.
OK or NG
OK >> Replace ECM.
NG >> Repair or replace malfunctioning part(s).
COMPONENT INSPECTION
Refrigerant Pressure Sensor
The refrigerant pressure sensor is attached to the liquid tank.
Make sure that the A/C refrigerant pressure and the sensor output
voltage are within the specified range as shown in the A/C operating
condition figure. Refer to EC-704, "
REFRIGERANT PRESSURE
SENSOR" (VQ35DE) or EC-1424, "REFRIGERANT PRESSURE
SENSOR" (VK45DE).
RJIA4080E
RJIA2954E

ATC-98
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
Insufficient CoolingNJS000GV
SYMPTOM: Insufficient cooling
INSPECTION FLOW
SJIA1777E

TROUBLE DIAGNOSIS
ATC-99
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Revision: 2007 April2007 M35/M45
*1ATC-57, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 2 to 6.*2ATC-82, "
Air Mix Door Motor Circuit"*3ATC-102, "Test Reading
(VQ35DE)" or ATC-103, "Test
Reading (VK45DE)"
*4ATC-63, "AUXILIARY MECHA-
NISM: TEMPERATURE SETTING
TRIMMER"
*5ATC-57, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.*6ATC-71, "
LAN System Circuit"
*7ATC-88, "Blower Motor Circuit"*8ATC-93, "Magnet Clutch Circuit"*9ATC-100, "PERFORMANCE TEST
DIAGNOSIS"
*10ATC-65, "Operational Check"*11AT C - 7 , "CONTAMINATED REFRIG-
ERANT"
*12EM-16, "Checking Drive Belts"
(VQ35DE) or EM-174, "
Checking
Drive Belts" (VK45DE)
*13EC-499, "
SYSTEM DESCRIPTION"
(VQ35DE) or EC-1214, "
SYSTEM
DESCRIPTION" (VK45DE)