ATC-34
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSISPFP:00004
How to Perform Trouble Diagnoses for Quick and Accurate RepairEJS004GO
WORK FLOW
SYMPTOM TABLE
*1ATC-65, "Operational Check"
SHA900E
Symptom Reference Page
A/C system does not come on. Go to Trouble Diagnosis Procedure for A/C System.ATC-67, "
Power
Supply and
Ground Circuit for
Auto Amp."
Air outlet does not change.
Go to Trouble Diagnosis Procedure for Mode Door Motor. (LAN)ATC-73, "Mode
Door Motor Cir-
cuit"Mode door motor does not operate normally.
Discharge air temperature does not change.
Go to Trouble Diagnosis Procedure for Air Mix Door Motor. (LAN)AT C - 7 6 , "
Air Mix
Door Motor Cir-
cuit"Air mix door motor does not operate nor-
mally.
Intake door does not change.
Go to Trouble Diagnosis Procedure for Intake Door Motor. (LAN)AT C - 7 9 , "
Intake
Door Motor Cir-
cuit"Intake door motor does not operate normally.
Blower motor operation is malfunctioning.
Go to Trouble Diagnosis Procedure for Blower Motor.AT C - 8 2 , "
Blower
Motor Circuit"Blower motor operation is malfunctioning
under out of starting fan speed control.
Magnet clutch does not engage. Go to Trouble Diagnosis Procedure for Magnet Clutch.AT C - 8 8 , "
Magnet
Clutch Circuit"
Insufficient cooling Go to Trouble Diagnosis Procedure for Insufficient Cooling.ATC-96, "Insuffi-
cient Cooling"
Insufficient heating Go to Trouble Diagnosis Procedure for Insufficient Heating.ATC-105, "Insuffi-
cient Heating"
Noise Go to Trouble Diagnosis Procedure for Noise.ATC-107, "Noise"
Self-diagnosis cannot be performed. Go to Trouble Diagnosis Procedure for Self-diagnosis.ATC-108, "Self-
Diagnosis"
ATC-96
TROUBLE DIAGNOSIS
Insufficient CoolingEJS004H2
SYMPTOM: Insufficient cooling
INSPECTION FLOW
*1ATC-65, "Operational Check".*2ATC-59, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 1.*3AT C - 5 9 , "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 5 to 7.
*4 QR engine; EM-13, "
Checking Drive
Belts" or YD engine; EM-140,
"Checking Drive Belts" .*5ATC-76, "
Air Mix Door Motor Circuit".*6ATC-100, "Test Reading (QR
Engine)" or ATC-101, "Test Reading
(YD Engine)" .
*7ATC-63, "
AUXILIARY MECHA-
NISM: TEMPERATURE SETTING
TRIMMER".*8ATC-59, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 9.*9AT C - 6 9 , "
LAN System Circuit".
SJIA0408E
ATC-102
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE
Whenever system’s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air tempera-
ture-to-operating pressure table).
Both High- and Low-pressure Sides are Too High
High-pressure Side is Too High and Low-pressure Side is Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure
sides are too high.Pressure is reduced soon after
water is splashed on con-
denser.Excessive refrigerant charge in
refrigeration cycleReduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cooling
performance
↓
1. Condenser fins are clogged.
2. Improper fan rotation of cool-
ing fan
Clean condenser.
Check and repair cooling fan
as necessary.
Low-pressure pipe is not
cold.
When compressor is stopped
high-pressure value quickly
drops by approximately 196
kPa (1.96 bar, 2 kg/cm
2 , 28
psi). It then decreases gradu-
ally thereafter.Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure decreases
too slowly.)
↓
Air in refrigeration cycleEvacuate repeatedly and
recharge system.
Engine tends to overheat.Engine cooling systems mal-
function.Check and repair each engine
cooling system.
An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.
Plates are sometimes cov-
ered with frost.
Excessive liquid refrigerant
on low-pressure side
Excessive refrigerant dis-
charge flow
Expansion valve is open a lit-
tle compared with the specifi-
cation.
↓
Improper expansion valve
adjustmentReplace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts
located between compressor
and condenser are clogged or
crushed.
Check and repair or replace
malfunctioning parts.
Check lubricant for contami-
nation.
AC360A
ATC-104
TROUBLE DIAGNOSIS
Low-pressure Side Sometimes Becomes Negative
Low-pressure Side Becomes Negative
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side sometimes
becomes negative.
Air conditioning system
does not function and does
not cyclically cool the com-
partment air.
The system constantly func-
tions for a certain period of
time after compressor is
stopped and restarted.Refrigerant does not dis-
charge cyclically.
↓
Moisture is frozen at expan-
sion valve outlet and inlet.
↓
Water is mixed with refriger-
ant.
Drain water from refrigerant
or replace refrigerant.
Replace liquid tank.
AC354A
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes nega-
tive.
Liquid tank or front/rear side of
expansion valve′s pipe is
frosted or dewed.High-pressure side is closed
and refrigerant does not flow.
↓
Expansion valve or liquid tank
is frosted.Leave the system at rest until
no frost is present. Start it
again to check whether or not
the malfunction is caused by
water or foreign particles.
If water is the cause, initially
cooling is okay. Then the
water freezes causing a
blockage. Drain water from
refrigerant or replace refrig-
erant.
If due to foreign particles,
remove expansion valve
and remove the particles
with dry and compressed air
(not shop air).
If either of the above meth-
ods cannot correct the mal-
function, replace expansion
valve.
Replace liquid tank.
Check lubricant for contami-
nation.
AC362A
HEATER & COOLING UNIT ASSEMBLY
ATC-131
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HEATER & COOLING UNIT ASSEMBLYPFP:27110
Removal and InstallationEJS000UT
REMOVAL
1. Use a refrigerant collecting equipment (for HFC-134a) to discharge refrigerant.
2. Drain coolant from cooling system. Refer to CO-9, "
Changing Engine Coolant" for QR engine or CO-32,
"Changing Engine Coolant" for YD engine.
3. Disconnect two heater hoses from heater core pipe.
4. Remove mounting bolt from low-pressure flexible hose.
CAUTION:
Cap or wrap the joint of the pipe with suitable material such
as vinyl tape to avoid the entry of air.
5. Remove the blower unit. Refer to ATC-125, "
BLOWER UNIT" .
6. Remove clips of vehicle harness from steering member.
7. Remove mounting nuts, and then remove instrument stay.
8. Remove mounting bolts from heater & cooling unit.
RJIA0060E
RJIA0061E
RJIA2444E
ATC-162
REFRIGERANT LINES
3. Check if the A/C refrigerant pressure is at least 345 kPa (3.45 bar, 3.52 kg/cm2 , 50 psi) above 16°C
(61°F). If less than specification, recover/evacuate and recharge the system with the specified amount of
refrigerant.
NOTE:
At temperatures below 16°C (61°F), leaks may not be detected since the system may not reach 345 kPa (3.45
bar, 3.52 kg/cm
2 , 50 psi).
4. Perform the leak test from the high-pressure side (compressor discharge a to evaporator inlet g) to the
low-pressure side (evaporator drain hose h to shaft seal k). Refer to ATC-143, "
Components" . Perform a
leak check for the following areas carefully. Clean the component to be checked and move the leak
detected probe completely around the connection/component.
Compressor
Check the fitting of high- and low- pressure hoses, relief valve and shaft seal.
Liquid tank
Check the refrigerant pressure sensor or dual pressure switch.
Service valves
Check all around the service valves. Ensure service valve caps are secured on the service valves (to pre-
vent leaks).
NOTE:
After removing A/C manifold gauge set from service valves, wipe any residue from valves to prevent any
false readings by leak detector.
Cooling unit (Evaporator)
With engine OFF, turn blower fan on “High” for at least 15 seconds to dissipate any refrigerant trace in the
cooling unit. Wait a minimum of 10 minutes accumulation time (refer to the manufacturer’s recommended
procedure for actual wait time) before inserting the leak detector probe into the drain hose.
Keep the probe inserted for at least 10 seconds. Use caution not to contaminate the probe tip with water
or dirt that may be in the drain hose.
5. If a leak detector detects a leak, verify at least once by blowing compressed air into area of suspected
leak, then repeat check as outlined above.
6. Do not stop when one leak is found. Continue to check for additional leaks at all system components.
If no leaks are found, perform steps 7-10.
7. Start engine.
8. Set the heater A/C control as follows;
a. A/C switch: ON
b. Mode control dial: VENT (Ventilation)
c. Intake position: Recirculation
d. Max. cold temperature
e. Fan speed: High
9. Run engine at 1,500 rpm for at least 2 minutes.
10. Turn engine off and perform leak check again following steps 4 through 6 above.
Refrigerant leaks should be checked immediately after stopping the
engine. Begin with the leak detector at the compressor. The pres-
sure on the high-pressure side will gradually drop after refrigerant
circulation stops and pressure on the low-pressure side will gradually
rise, as shown in the graph. Some leaks are more easily detected
when pressure is high.
11. Discharge A/C system using approved refrigerant recovery equipment. Repair the leaking fitting or com-
ponent if necessary.
12. Evacuate and recharge A/C system and perform the leak test to confirm no refrigerant leaks.
SHA839E
HEATER UNIT
MTC-27
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MTC
HEATER UNITPFP:27100
Removal and InstallationEJS001F9
REMOVAL
1. Drain coolant from cooling system. Refer to CO-9, "Changing Engine Coolant" for QR engine or CO-32,
"Changing Engine Coolant" for YD engine.
2. Disconnect two heater hoses from heater core pipe.
3. Remove instrument panel. Refer to IP-11, "
Removal and Installation" .
4. Remove blower unit. Refer to MTC-22, "
BLOWER UNIT" .
5. Remove clips of vehicle harness from steering member.
6. Remove mounting nuts, and then remove instrument stay.
7. Remove mounting bolts from heater (& cooling) unit.
RJIA0060E
RJIA0061E
RJIA2444E
HARNESS
PG-65
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Wiring Diagram Codes (Cell Codes) EKS0032J
Use the chart below to find out what each wiring diagram code stands for.
Refer to the wiring diagram code in the alphabetical index to find the location (page number) of each wiring
diagram.
Code Section Wiring Diagram Name
1STSIG AT A/T 1st Signal
2NDSIG AT A/T 2nd Signal
3RDSIG AT A/T 3rd Signal
4THSIG AT A/T 4th Signal
4WD TF 4WD Control system
A/C ATC Air Conditioner
ABS BRC Anti-Lock Brake System
APP1PW EC Accelerator Pedal Position Sensor 1 Power Supply
APP2PW EC Accelerator Pedal Position Sensor 2 Power Supply
APPS1 EC Accelerator Pedal Position Sensor
APPS2 EC Accelerator Pedal Position Sensor
APPS3 EC Accelerator Pedal Position Sensor
ASC/BS EC Automatic Speed Control Device (ASCD) Brake Switch
ASC/SW EC Automatic Speed Control Device (ASCD) Steering Switch
ASCBOF EC Automatic Speed Control Device (ASCD) Brake Switch
ASCIND EC Automatic Speed Control Device (ASCD) Indicator
AT/IND DI A/T Indicator Lamp
AUDIO AV Audio
BA/FTS AT A/T Fluid Temperature Sensor and TCM Power Supply
BACK/L LT Back-Up Lamp
BOOST EC Turbocharger Boost Sensor
BRK/SW EC Brake Switch
CAN AT CAN Communication Line
CAN EC CAN Communication Line
CAN LAN CAN System
CHARGE SC Charging System
CHIME DI Warning Chime
CIGAR WW Cigarette Lighter
CKPS EC Crankshaft Position Sensor
CLOCK DI Clock
CMPS EC Camshaft Position Sensor
COOL/F EC Cooling Fan Control
D/LOCK BL Power Door Lock
DEF GW Rear Window Defogger
DTRL LT Headlamp - With Daytime Light System
ECM/PW EC ECM Power Supply for Back-Up
ECMRLY EC ECM Relay
ECTS EC Engine Coolant Temperature Sensor
EGRVLV EC EGR Volume Control Valve
EGVC/V EC EGR Volume Control Valve
ENGSS AT Engine Speed Signal