1996 TOYOTA LAND CRUISER cooling

 DTC No.
Indicates the diagnostic trouble code.
 Page or Instructions
Indicates the page where the inspection procedure
for each circuit is to be found, or gives instructions
for checking and repairs. Detection Item
Indicates the system of the problem or
contents of the problem.  Trouble Area
Indicates the suspect area of the
problem.
Mass
Air Flow Circuit MalfunctionDetection Item
 Open or short in mass air flow meter circuit
 Mass air flow meter
 ECM
DTC No.
(See page)
Trouble Area
MIL* MemoryP0100
(DI−24)
P0101
(DI−28)
P0115
(DI−33)  Open or short in intake air temp. sensor
circuit
 Intake air temp. sensor
 ECM
Intake Air Temp. Circuit
Malfunction
P0110
(DI−29)
 Open or short in engine coolant temp. sensor circuit
 Engine coolant temp. sensor
 ECM
Throttle/ Pedal Position Sensor/Switch
”A” Circuit MalfunctionEngine Coolant Temp.
Circuit Malfunction
 Open or short in throttle position sensor circuit
 Throttle position sensor
 ECM
HINT:
Parameters listed in the chart may not be exactly the same as your readi\
ng due to the type of instrument or other
factors.
If a malfunction code is displayed during the DTC check mode, check the circ\
uit for the code listed in the table
below. For details of each code, turn to the page referred to under the ”See\
page” for the respective ”DTC No.”
in the DTC chart.
Mass Air Flow Circuit
Range/ Performance Problem Mass air flow meter
 Throttle position sensor
Throttle/
Pedal Position Sensor/ Switch
”A” Circuit Range / Performance Prob-
lem
P0116
(DI−37)
Engine Coolant Temp.
Circuit
Range/ Performance Problem Engine coolant temp. sensor
 Cooling system
SAE CONTROLLED
DIAGNOSTIC TROUBLE CODE CHART
IN−24−
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 LAND CRUISER (RM451U)
4. DIAGNOSTIC TROUBLE CODE CHART
The inspection procedure is shown in the table below. This ta ble permits efficient and accurate troubleshoot-
ing using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with trouble-
shooting in accordance with the inspection procedure given in the diagnostic cha\
rt corresponding to the
diagnostic trouble codes displayed. The engine diagnostic trouble code chart is sho\
wn below as an example.
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AC2810
AC2QA−01
AC2811
N11084
Wrong Okay
LO HI LOHI
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−1
1328
Author: Date:
1996 LAND CRUISER (RM451U)
AIR CONDITIONING SYSTEM
PRECAUTION
1. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED
AREA OR NEAR AN OPEN FLAME
2. ALWAYS WEAR EYE PROTECTION
3. BE CAREFUL THAT LIQUID REFRIGERANT DOES NOT GET IN YOUR EYES OR ON YOUR SKIN
If liquid refrigerant gets in your eyes or on your skin:
(a) Wash the area with lots of cool water.
CAUTION:
Do not rub your eyes or skin.
(b) Apply clean petroleum jelly to the skin.
(c) Go immediately to a physician or hospital for professional treatment.
4. NEVER HEAT CONTAINER OR EXPOSE IT TO NAKED
FLAME
5. BE CAREFUL NOT TO DROP CONTAINER AND NOT TO APPLY PHYSICAL SHOCKS TO IT
6. DO NOT OPERATE COMPRESSOR WITHOUT ENOUGH REFRIGERANT IN REFRIGERANT SYSTEM
If there is not enough refrigerant in the refrigerant system oil lu-
brication will be insuf ficient and compressor burnout may occur,
so take care to avoid this.
7. DO NOT OPEN HIGH PRESSURE MANIFOLD VALVE WHILE COMPRESSOR IS OPERATING
If the high pressure valve is opened, r efrigerant flows in the re-
verse direction and could cause the charging cylinder to rup-
ture, so open and close the only low pressure valve.
8. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH
REFRIGERANT
If refrigerant is overcharged, it causes problems such as insuffi-
cient cooling, poor fuel economy, engine overheating etc.
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AC−4
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
1996 LAND CRUISER (RM451U)
Insuf
ficient cooling
1. Refrigerant volume
2. Drive belt
3. Magnetic clutch
4. Compressor
5. Condenser
6. Receiver
7. Expansion valve
8. Evaporator
9. Refrigerant line
10.Pressure switch
11. A/C amplifier
12.A/C control assemblyAC−5
AC−15
AC−33
AC−33
AC−42
AC−39
AC−47
AC−45
AC−20
AC−61
AC−74
AC−69
No engine idle up when A/C switch ON
1. A/C amplifier
2. ECM
3. Wire harnessAC−74 −
−
No warm air comes out
1. Engine coolant volume
2. A/C control assembly
3. Water valve
4. Heater radiator−
AC−69
AC−49
AC−46
A/C indicator does not light up when mode lever at DEF. position
1. Defroster mode switch
2. A/C switch
3. Wire harnessAC−69
AC−69 −
Rear heater:
SymptomSuspect AreaSee page
No blower operation
1. RR HTR Fuse
2. Rear heater relay
3. Rear heater switch
4. Rear blower motor
5. Rear blower resistor−
AC−65
AC−77
AC−55
AC−58
No warm air come out1. Engine coolant volume
2. Rear heater radiator−
AC−46
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N14063
AC2QD−01
I01386
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−5
1996 LAND CRUISER (RM451U)
ON−VEHICLE INSPECTION
1. INSPECT REFRIGERANT VOLUME
Observe the sight glass on the liquid tube.
Test conditions:
Running engine at 1,500 rpm
Blower speed control switch set at ”HI”
A/C switch ON
Temperature control set at ”MAX. COOL”
Fully open doors
ItemSymptomAmount of refrigerantRemedy
1Bubbles present in sight glassInsufficient*
1. Check for gas leakage with gas leak
tester and repair if necessary
2. Add refrigerant until bubbles disappear
2No bubbles present in sight glassNone, sufficient or too muchRefer to items 3 and 4
3No temperature difference between compressor inlet and outletEmpty or nearly empty
1. Check for gas leakage with gas leaktester and repair if necessary
2. Add refrigerant until bubbles disappear
4Temperature between compressor inlet and outlet is noticeably differentCorrect or too muchRefer to items 5 and 6
5Immediately after air conditioning is turnedoff, refrigerant in sight glass stays clearToo much
1. Discharge refrigerant
2. Evacuate air and charge proper amount of purified refrigerant
6When air conditioning is turned off,
refrigerant foams and then stays clearCorrect−
*: Bubbles in the sight glass with ambient temperatures higher
than usual can be considered normal if cooling is sufficient.
2. INSPECT REFRIGERAT PRESSURE WITH MANIFOLD
GAUGE SET
This is a method in which the trouble is located by using a man-
ifold gauge set. Read the manifold gauge pressure when the
these conditions are established:
Test conditions:
Temperature at the air inlet with the switch set at RECIRC
is 30 − 35° C (86 − 95° F)
Engine running at 1,500 rpm
Blower speed control switch set at high
Temperature control set at max. cool
HINT:
It should be noted that the gauge indications may vary slightly
due to ambient temperature conditions.
(1) Normally functioning refrigeration system.
Gauge reading:
Low pressure side:
0.15 − 0.25 MPa (1.5 − 2.5 kgf/cm
2)
High pressure side:
1.37 − 1.57 MPa (14 − 15 kgf/cm
2)
SightGlass
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I01387
Condition : Periodically cools and then fails to cool
I01388
Condition: Insufficient cooling
AC−6
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
1996 LAND CRUISER (RM451U)
(2) Moisture present in refrigeration system.
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
During operation, pressure on low
pressure side sometimes become
a vacuum and sometime normal
Moisture entered in refrigeration
system freezes at expansion valve
orifice and temporarily stops cycle,
but normal state is restored after a
time when the ice melts Drier in oversaturated state
 Moisture in refrigeration system
freezes at expansion valve orifice
and blocks circulation of refriger-
ant(1) Replace condenser
(2) Remove moisture in cycle
through repeatedly evacuating air
(3) Charge proper amount of new
refrigerant
(3) Insufficient cooling
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure low on both low and
high pressure sides
 Bubbles seen in sight glass con-
tinuously
 Insufficient cooling performance
Gas leakage at some place in re-
frigeration system Insufficient refrigerant in system
 Refrigerant leaking
(1) Check for gas leakage with gas
leak detector and repair if neces-
sary
(2) Charge proper amount of re-
frigerant
(3) If indicated pressure value is
near 0 when connected to gauge,
create the vacuum after inspecting
and repairing the location of the
leak
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I01389
Condition: Insufficient cooling
I01449
Condition: Does not cool (Cools from time to time in some cases)
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−7
1996 LAND CRUISER (RM451U)
(4) Poor circulation of refrigerant
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure low in both low and
high pressure sides
 Frost on tube from condenser to
unit
Refrigerant flow obstructed by dirt
in condensercondenser cloggedReplace condenser
(5) Refrigerant does not circulate
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Vacuum indicated on low pres-
sure side, very low pressure indi-
cated on high pressure side
 Frost or dew seen on piping be-
fore and after condenser/ drier or
expansion valve Refrigerant flow obstructed by
moisture or dirt in refrigeration sys-
tem
 Refrigerant flow obstructed by
gas leakage from expansion valve
Refrigerant does not circulate
(1) Check expansion valve
(2) Clean out dirt in expansion
valve by blowing with air
(3) Replace condenser
(4) Evacuate air and charge new
refrigerant to proper amount
(5) For gas leakage from expan-
sion valve, replace expansion
valve
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I01390
Condition: Insufficient cooling
I01392
Condition: Insufficient coolingNOTE : These gauge indica-
tions are shown when the
refrigeration system has
been opened and the refrig-
erant charged without vacu-
um purging.
AC−8
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
1996 LAND CRUISER (RM451U)
(6) Refrigerant overcharged or insufficient cooling of
condenser
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 No air bubbles seen through the
sight glass even when the engine
rpm is lowered Unable to develop sufficient per-
formance due to excessive refrig-
eration system
 Insufficient cooling of condenser Excessive refrigerant in
cycle → refrigerant over charged
 Condenser cooling → condenser
fins clogged or cooling fan faulty
(1) Clean condenser
(2) Check cooling fan with fluid
coupling operation
(3) If (1) and (2) are in normal
state, check amount of refrigerant
Charge proper amount of refriger-
ant
(7) Air present in refrigeration system
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 The low pressure piping hot to
touch
 Bubbles seen in sight glass
Air entered in refrigeration system
 Air present in refrigeration sys-
tem
 Insufficient vacuum purging
(1) Check compressor oil to see if
it is dirty or insuf ficient
(2) Evacuate air and charge new
refrigerant
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I01450
Condition: Insufficient cooling
I01393
Condition : Does not cool
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−9
1996 LAND CRUISER (RM451U)
(8) Expansion valve improperly
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 Frost or large amount of dew on
piping on low pressure side
Trouble in expansion valve
 Excessive refrigerant in low
pressure piping
 Expansion valve opened too
wide
Check expansion valve
Replace if defective
(9) Defective compression compressor
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on low and
high pressure sides
 Pressure too low on high pres-
sure side
Internal leak in compressor
 Compression defective
 Valve leaking or broken sliding
parts
Repair or replace compressor
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