Page 505 of 4449
ATC-76
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
Intake Door Motor CircuitAJS0014W
SYMPTOM:
Intake door does not change.
Intake door motor does not operate normally.
INSPECTION FLOW
*1AT C - 5 4 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6.*2ATC-104, "
Ambient Sensor Circuit".*3ATC-107, "In-vehicle Sensor Circuit".
*4AT C - 11 0 , "
Sunload Sensor Circuit".*5AT C - 7 3 , "Air Mix Door Motor Cir-
cuit".*6AT C - 5 4 , "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*7AT C - 6 6 , "
LAN System Circuit".*8ATC-124, "INTAKE DOOR
MOTOR".*9AT C - 6 1 , "
Operational Check".
*10AT C - 4 2 , "
SYMPTOM TABLE".*11AT C - 11 3 , "Intake Sensor Circuit".
RJIA1993E
Page 506 of 4449
TROUBLE DIAGNOSIS
ATC-77
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 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 DEFROST, or OFF switches are pushed or A/C switch is
OFF, the unified meter and A/C amp. sets the intake door at the FRESH position.
Intake Door Control Specification
RJIA1786E
RJIA1787E
Page 507 of 4449
ATC-78
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
COMPONENT DESCRIPTION
Intake Door Motor
The intake door motor is attached to the intake 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.
DIAGNOSTIC PROCEDURE FOR INTAKE DOOR MOTOR
SYMPTOM: Intake door motor does not operate normally.
Perform diagnostic procedure for AT C - 6 6 , "
DIAGNOSTIC PROCEDURE FOR LAN CIRCUIT" .
RJIA0897E
Page 508 of 4449
TROUBLE DIAGNOSIS
ATC-79
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 FX35/FX45
Blower Motor CircuitAJS0014X
SYMPTOM:
Blower motor operation is malfunctioning.
Blower motor operation is malfunctioning under out of starting fan speed control.
INSPECTION FLOW
*1ATC-61, "Operational Check".*2AT C - 11 3 , "Intake Sensor Circuit".*3ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No.4.
*4ATC-54, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No.6.*5AT C - 5 4 , "
FUNCTION CONFIRMA-
TION PROCEDURE", see No.13.*6ATC-81, "
DIAGNOSTIC PROCE-
DURE FOR BLOWER MOTOR".
RJIA1994E
Page 509 of 4449

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
Page 510 of 4449

TROUBLE DIAGNOSIS
ATC-81
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 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), 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 pushed. The blower speed will gradually
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
low speed is usual low speed (duty ratio 25%). During high sunload conditions, the unified meter and A/C
amp. causes the blower speed to increase (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.
DIAGNOSTIC PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning under starting
fan speed control.
RJIA1996E
ZHA152H
SJIA0266E
Page 511 of 4449

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
RJIA1997E
3 – Ground : Continuity should exist.
RJIA1998E
2 – 53 : Continuity should exist.
RJIA1999E
RJIA2000E
Page 512 of 4449
TROUBLE DIAGNOSIS
ATC-83
C
D
E
F
G
H
I
K
L
MA
B
AT C
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.
RJIA2001E
RJIA0905E