Page 536 of 5621
TROUBLE DIAGNOSIS
ATC-89
C
D
E
F
G
H
I
K
L
MA
B
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
Page 537 of 5621
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
Page 541 of 5621
ATC-94
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
Magnet Clutch CircuitNJS000GU
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1ATC-122, "Intake Sensor Circuit"*2ATC-113, "Ambient Sensor Circuit"*3AT C - 5 6 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*4ATC-95, "
DIAGNOSIS PROCE-
DURE FOR MAGNET CLUTCH"
*5ATC-105, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"
*6AT C - 6 4 , "Operational Check"
*7ATC-56, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 2 to 6.*8ATC-41, "
SYMPTOM TABLE"
RJIA4077E
Page 542 of 5621
TROUBLE DIAGNOSIS
ATC-95
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2006 January2006 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
2C (28F), the compres-
sor turns ON. The compressor turns OFF when ambient temperature
is lower than
5C (23F).
When intake air temperature is higher than 1
C (34F), the compres-
sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than
5C (23F).
DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
RHA094GB
SJIA0267E
RJIA4078E
Page 543 of 5621

ATC-96
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
1. CHECK AMBIENT SENSOR AND INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to AT C - 5 6 , "
FUNCTION CONFIRMATION PROCEDURE" ,
see No. 9 and 11.
OK or NG
OK >> GO TO 2.
NG >>
Malfunctioning ambient sensor: Refer to AT C - 11 3 , "Ambient Sensor Circuit" .
Malfunctioning intake sensor: Refer to ATC-122, "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 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 6 , "
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 6 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-4. Confirm that magnet clutch operation normal.
34 – 1 : Continuity should exist.
RJIA4079E
RJIA2005E
Page 544 of 5621

TROUBLE DIAGNOSIS
ATC-97
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2006 January2006 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-149, "
CONSULT-II Reference Value in Data
Monitor" (VQ35DE) or EC-862, "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-692, "
REFRIGERANT PRESSURE SENSOR" (VQ35DE) or EC-1434, "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
Page 545 of 5621
ATC-98
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
8. CHECK CAN COMMUNICATION
Check CAN communication. Refer to EC-173, "
DTC U1000, U1001 CAN COMMUNICATION LINE"
(VQ35DE) or EC-886, "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-692, "
REFRIGERANT PRESSURE
SENSOR" (VQ35DE) or EC-1434, "REFRIGERANT PRESSURE
SENSOR" (VK45DE).
RJIA4080E
RJIA2954E
Page 553 of 5621

ATC-106
TROUBLE DIAGNOSIS
Revision: 2006 January2006 M35/M45
High-pressure Side is Too Low and Low-pressure Side is Too High
Both High- and Low-pressure Sides are Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low and
low-pressure side is too high.High- and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure opera-
tion is improper.
Damaged inside compressor
packings.Replace compressor.
No temperature difference
between high- and low-pres-
sure sides.Compressor pressure opera-
tion is improper.
Damaged inside compressor
packings.Replace compressor.AC356A
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low.
There is a big temperature
difference between liquid
tank outlet and inlet. Outlet
temperature is extremely
low.
Liquid tank inlet and expan-
sion valve are frosted.Liquid tank inside is slightly
clogged.
Replace liquid tank.
Check lubricant for contami-
nation.
Temperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.
Expansion valve inlet may
be frosted.
Temperature difference
occurs somewhere in high-
pressure side.High-pressure pipe located
between liquid tank and
expansion valve is clogged.
Check and repair malfunc-
tioning parts.
Check lubricant for contami-
nation.
Expansion valve and liquid
tank are warm or slightly cool
when touched.Low refrigerant charge.
Leaking fittings or compo-
nents.Check refrigerant for leaks.
Refer to ATC-170, "Checking
for Refrigerant Leaks" .
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.Expansion valve closes a little
compared with the specifica-
tion.
1. Improper expansion valve
adjustment.
2. Malfunctioning expansion
valve.
3. Outlet and inlet may be
clogged.
Remove foreign particles by
using compressed air.
Replace expansion valve.
Check lubricant for contami-
nation.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.Low-pressure pipe is clogged
or crushed.
Check and repair malfunc-
tioning parts.
Check lubricant for contami-
nation.
Air flow volume is not enough
or is too low.Evaporator is frozen.
Check intake sensor circuit.
Refer to ATC-122, "
Intake
Sensor Circuit" .
Replace compressor.
Repair evaporator fins.
Replace evaporator.
Refer to AT C - 8 9 , "Blower
Motor Circuit" .
AC353A