INFINITI M35 2006 Factory Service Manual

ATC-84
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
SYSTEM DESCRIPTION
Component Parts
Air mix door control system components are:
Unified meter and A/C amp.
Air mix door motor (LCU)
A/C LAN system (PBR built-in mode door motor, upper ventilator door motor, air mix door motor and
intake door motor)
In-vehicle sensor
Ambient sensor
Sunload sensor
Intake sensor
System Operation
The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends air mix door, mode door, upper ventilator door and intake door opening angle data to the air mix door
motor LCUs, mode door motor LCUs, upper ventilator door motor LCU and intake door motor LCU.
The air mix door motors, mode door motors, upper ventilator door motor and intake door motor read their
respective signals according to the address signal. Opening angle indication signals received from the unified
meter and A/C amp. and each of the motor position sensors are compared by the LCUs in each door motor
with the existing decision and opening angles. Subsequently, HOT/COLD, DEF/VENT, OPEN/SHUT and FRE/
REC operation is selected. The new selection data are returned to the unified meter and A/C amp.
Air Mix Door Control Specification
RJIA4217E
RJIA1782E

TROUBLE DIAGNOSIS
ATC-85
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AT C
Revision: 2006 January2006 M35/M45
COMPONENT DESCRIPTION
Air Mix Door Motor
The air mix door motors are attached to the heater & cooling unit
assembly. It rotates so that the air mix door is opened or closed to a
position set by the unified meter and A/C amp. Motor rotation is then
conveyed through a shaft and the air mix door position feedback is
then sent to the unified meter and A/C amp. by PBR built-in air mix
door motor.
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR
SYMPTOM: Discharge air temperature does not change.
Perform diagnosis procedure. Refer to AT C - 7 0 , "
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
Air Mix Door Motor PBR CircuitNJS000GR
SYMPTOM:
Discharge air temperature does not change.
PBR circuit is open or shorted.
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR PBR
Perform diagnosis procedure. Refer to AT C - 7 0 , "DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
RJIA4064E
RJIA4065E

ATC-86
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
Intake Door Motor CircuitNJS000GS
SYMPTOM:
Intake door does not change.
Intake door motor does not operate normally.
INSPECTION FLOW
*1AT C - 5 6 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 2 to 6.*2ATC-113, "
Ambient Sensor Circuit"*3AT C - 11 6 , "In-Vehicle Sensor Circuit"
*4AT C - 11 9 , "Sunload Sensor Circuit"*5ATC-83, "Air Mix Door Motor Cir-
cuit"
*6AT C - 5 6 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*7AT C - 7 0 , "
LAN System Circuit"*8ATC-133, "INTAKE DOOR
MOTOR"
*9AT C - 6 4 , "Operational Check"
*10AT C - 4 1 , "SYMPTOM TABLE"*11ATC-122, "Intake Sensor Circuit"
RJIA4066E

TROUBLE DIAGNOSIS
ATC-87
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AT C
Revision: 2006 January2006 M35/M45
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, upper ventilator 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 shifting mode position D/F, when the DEF or OFF switches
are pressed, or when A/C switch is OFF, the unified meter and A/C amp. sets the intake door at the FRESH
position.
Intake Door Control Specification
RJIA4214E
RJIA4067E

ATC-88
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
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 - 7 0 , "
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
RJIA4068E

TROUBLE DIAGNOSIS
ATC-89
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AT C
Revision: 2006 January2006 M35/M45
Blower Motor CircuitNJS000GT
SYMPTOM: Blower motor operation is malfunctioning.
INSPECTION FLOW
*1ATC-64, "Operational Check"*2ATC-122, "Intake Sensor Circuit"*3ATC-56, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 2.
*4ATC-56, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 6.*5AT C - 5 6 , "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.*6ATC-91, "
DIAGNOSIS PROCE-
DURE FOR BLOWER MOTOR"
*7ATC-41, "SYMPTOM TABLE"*8AT C - 11 3 , "Ambient Sensor Circuit"*9ATC-116, "In-Vehicle Sensor Circuit"
*10ATC-119, "Sunload Sensor Circuit"*11EC-226, "DTC P0117, P0118 ECT
SENSOR" (VQ35DE) or EC-948,
"DTC P0117, P0118 ECT SEN-
SOR" (VK45DE)
RJIA4069E

ATC-90
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
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, upper ventilator 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.
RJIA4070E

TROUBLE DIAGNOSIS
ATC-91
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AT C
Revision: 2006 January2006 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 (133F), 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 (133F), at which time 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

ATC-92
TROUBLE DIAGNOSIS
Revision: 2006 January2006 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 P G - 111 ,
"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

TROUBLE DIAGNOSIS
ATC-93
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AT C
Revision: 2006 January2006 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. 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