ISUZU AXIOM 2002 Service Workshop Manual

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±25
Checking The Refrigerant System With Manifold Gauge
Since Refrigerant-134a (HFC-134a) is used in the air
conditioning system in this vehicle, be sure to use
manifold gauges, charging hoses and other air
conditioning service tools for HFC-134a when
checking the refrigerant system.
Conditions:

Run the engine at idle

Air conditioning switch is ªONº

Run the blower motor at ªHIGHº position (5 positions)

Temperature control set to ªMAX COLDº (65
F)

Air source selector at ªCIRCº

Open the engine hood

Close all the doors
Normal Pressure:

At ambient temperature: approx. 25±30
C
(77±86
F).

At low-pressure side: approx. 147.1±294.2 kPa
(21.3±42.7 psi).

At high-pressure side: approx. 1372.9±1863.3 kPa
(199.1±270.2 psi).
Refer to the table on the refrigerant pressure-temperature
relationship.
HFC-134a Pressure-Temperature Relationship
PressureTemperature
(kPa)(psi)(
C)(
F)
365.3±20±4.4
679.7±155
10415±1014
14721±523
19628032
25537541
314451050
392571559
471682068
569822577
677983086
78511 43595
91213240104
10591544511 3
121617650122

1A±26
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Connect The Manifold Gauge
Low-pressure hose (LOW) Ð Suction side
High pressure hose (HI) Ð Discharge side
901R100020
Legend
(1) Low Side
(2) High Side

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±27
ConditionPossible causeCorrection
Discharge (High Gauge) Pressure
Abnormally High
Condenser clogged or dirty.Clean the condenser fins
Abnormally HighCooling fan does not operate
properly.Check the cooling fan operation.
Discharge (High Gauge) Pressure
Abnormally High.
Insufficient cooling.Excessive refrigerant in system.Discharge and recover refrigerant.
Recharge to specified amount.
Discharge (High Gauge) Pressure
Abnormally High.
High pressure gauge drop. (After
stopping A/C, the pressure drops
approx. 196 kPa (28 psi) quickly)Air in system.Evacuate and charge refrigerant
system.
Discharge (High Gauge) Pressure
Abnormally Low.
Insufficient coolingInsufficient refrigerant in system.Check for leaks. Discharge and
recover the refrigerant. Recharge to
the specified amount.
Discharge (High Gauge) Pressure
Abnormally Low.
Low pressure gauge indicates
vacuum.Clogged or defective expansion
valve.Replace the expansion valve.
Discharge (High Gauge) Pressure
Abnormally Low.
Frost or dew on refrigerant line
before and after the receiver/drier or
expansion valve, and low pressure
gauge indicates vacuum.Restriction caused by debris or
moisture in the receiver/drier.Check system for restriction and
replace the receiver/drier.
Discharge (High Gauge) Pressure
Abnormally Low.Compressor seal defectiveRepair or replace the compressor.
High and low pressure gauge
balanced quickly. (After turned off
A/C)Poor compression due to a defective
compressor gasket.Repair or replace the compressor.
Suction (Low Gauge) Pressure
Abnormally High.
Low pressure gauge (Low pressure
gauge is lowered after condenser is
cooled by water.)Excessive refrigerant in system.Discharge and recover refrigerant
Recharge to specified amount.
Suction (Low Gauge) Pressure
Abnormally High.
Low pressure hose temperature.
(Low pressure hose temperature
around the compressor refrigerant
Unsatisfactory valve operation due
to defective temperature sensor of
expansion valve.Replace the expansion valve.
around the com ressor refrigerant
line connector is lower than around
evaporator.)Expansion valve opens too long.Replace the expansion valve.
Suction (Low Gauge) Pressure
Abnormally High.
High and low pressure gauge
balanced quickly. (After turned off
A/C)Compressor gasket is defective.Repair or replace the compressor.
Suction (Low Gauge) Pressure
Abnormally Low.
Insufficient cooling.Insufficient refrigerant in system.Check for leaks. Discharge and
recover the refrigerant. Recharge to
specified amount.
Suction (Low Gauge) Pressure
Abnormally Low.
Frost on the expansion valve inlet
lineExpansion valve clogged.Replace the expansion valve.

1A±28
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Condition CorrectionPossible cause
Suction (Low Gauge) Pressure
Abnormally Low
Receiver/drier inlet and outlet
refrigerant line temperature. (A
distinct difference in temperature
develops.)Receiver/Drier clogged.Replace the receiver/drier.
Suction (Low Gauge) Pressure
Abnormally Low.
Expansion valve outlet refrigerant
line. (Not cold and low pressure
gauge indicates vacuum.)Expansion valve temperature sensor
is defective.Replace the expansion valve.
Suction (Low Gauge) Pressure
Abnormally Low.
When the refrigerant line is clogged
or blocked, the low pressure gauge
reading will decrease, or a vacuum
reading may be shown.Clogged or blocked refrigerant line.Replace refrigerant line.
Suction (Low Gauge) Pressure
Abnormally Low.
Evaporator core is frozen.Thermo switch defective.Replace thermo switch.
Suction (Low Gauge) and Discharge
(High Gauge) Pressure Abnormally
High.Excessive refrigerant in system.Discharge and recover the
refrigerant, the Recharge to the
specified amount.
Insufficient cooling.Condenser clogged or dirty.Clean the condenser fin.
Suction (Low Gauge) and Discharge
(High Gauge) Pressure Abnormally
High.
Suction (Low) pressure hose (Not
cold).Air in system.Evacuate and charge refrigerant.
Suction (Low Gauge) and Discharge
(High Gauge) Pressure Abnormally
Low.
Insufficient coolingInsufficient refrigerant in system.Check for leaks. Discharge and
recover refrigerant. Recharge to
specified amount.
A/C Ð Air Conditioning

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±29
Condenser Fan Diagnosis
While the air conditioning is ON, the cycling switch in the
triple pressure switch senses the refrigerant pressure,
and activates the condenser fan to improve the cooling
capacity of the condenser when the refrigerant pressure
exceeds a set pressure value. The condenser fan stops
when the air conditioning is turned ªOFFº or when the
pressure goes down below the set pressure value.
D08R200041
ConditionPossible causeCorrection
Condenser fan does not run.±Refer to ªChart Aº.
±Refer to ªChart Bº.

1A±30
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Chart ªAº Condenser Fan Does Not Run
StepActionYe sNo
1Are 30A fuse normal?Go to Step 2Replace
2Is relay (X-16) normal?Go to Step 3Replace
3Is pressure switch normal?
Go to Step 4
Switch defective
or insufficient
refrigerant.
4Is fan motor normal?Go to Step 5Replace
51. Disconnect condenser fan relay (X-16).
2. Check to see if battery voltage is present at the chassis side
relay terminal NO. X16-5.
Is there a battery voltage?
Go to Step 6
Repair open
circuit between
Condenser Fan
fuse (30A) and
No.X16-5.
61. Reconnect condenser fan relay (X-16).
2. Check to see if battery voltage is present at chassis side
connector terminal No.C21-3.
Is there a battery voltage?
Go to Step 7
Repair open
circuit between
fuse (10A) and
C21-3.
7Check to see if continuity between chassis side relay terminal
No.X16-2 and the chassis side connector terminal No.C21-4.
Is there a continuity?
Go to Step 8
Repair open
circuit.
8Check to see if continuity between chassis side connector
terminal No. C16-1 and chassis side relay terminal No.X16-1.
Is there a continuity?Poor ground or
open circuit
between chassis
side connector
terminal
No.X16-4 (or
No.C16-2) and
body ground
(No.C10).
Repair open
circuit.
Chart ªBº Condenser Fan Does Not Stop
StepActionYe sNo
11. Disconnect the triple pressure connector.
Does condenser fan stop?
Replace the triple
pressure switch.
Replace the
condenser fan
relay.

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±31
Air Conditioning System
Individual Inspection
Triple Pressure Switch (V6, A/T)
1. Disconnect the connector and check for continuity
between pressure switch side connector terminals (1)
and (2).
2. Reconnect the connector to activate the A/C switch,
and check to see if there is continuity between the
chassis side connector terminals (3) and (4) and the
fan operates.
875RY00010
Condenser Fan
1. Disconnect the condenser fan connector.
2. Connect the battery positive terminal to the
condenser fan side connector terminal No.C-16-1
and negative to the No.C-16-2.
3. Check that condenser fan is rotating correctly.
875R200002
General Repair Procedure
Precautions For Replacement or Repair of
Air Conditioning Parts
There are certain procedures, practices and precautions
that should be followed when servicing air conditioning
systems:

Keep your work area clean.

Always wear safety goggles and protective gloves
when working on refrigerant systems.

Beware of the danger of carbon monoxide fumes
caused by running the engine.

Beware of discharged refrigerant in enclosed or
improperly ventilated garages.

Always disconnect the negative battery cable and
discharge and recover the refrigerant whenever
repairing the air conditioning system.

When discharging and recovering the refrigerant, do
not allow refrigerant to discharge too fast; it will draw
compressor oil out of the system.

Keep moisture and contaminants out of the system.
When disconnecting or removing any lines or parts,
use plugs or caps to close the fittings immediately.
Never remove the caps or plugs until the lines or parts
are reconnected or installed.

When disconnecting or reconnecting the lines, use
two wrenches to support the line fitting, to prevent
from twisting or other damage.

Always install new O-rings whenever a connection is
disassembled.

Before connecting any hoses or lines, apply new
specified compressor oil to the O-rings.

When removing and replacing any parts which
require discharging the refrigerant circuit, the
operations described in this section must be
performed in the following sequence:
1. Use the J-39500 (ACR
4: HFC-134a Refrigerant
Recovery / Recycling / Recharging / System) or
equivalent to thoroughly discharge and recover the
refrigerant.
2. Remove and replace the defective part.
3. After evacuation, charge the air conditioning
system and check for leaks.

1A±32
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Repair Of Refrigerant Leaks
Refrigerant Line Connections
Install new O-rings, if required. When disconnecting or
connecting lines, use two wrenches to prevent the
connecting portion from twisting or becoming damaged.
852R200001When connecting the refrigerant line at a block joint,
securely insert the projecting portion of the joint portion
into the connecting hole on the unit side and secure with a
bolt. Apply the specified compressor oil to the O-rings
prior to connecting.
CAUTION: Compressor (PAG) oil to be used varies
according to the compressor model. Be sure to apply
oil specified for the model of compressor.
850RW002
O-rings (2) must be fitted in the groove (1) of refrigerant
line.
850RW003Insert the nut into the union.
First, tighten the nut by hand as much as possible, then
tighten the nut to the specified torque.
850RW004

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±33
Leak Check
Inspection of refrigerant leak
Refrigerant leak may cause an adverse effect not only on
the performance and durability of each component of the
air±conditioner, but also on the global atmosphere.
Therefore, it is most important to repair refrigerant leak
when there is any leak found.
Inspection flow of refrigerant leak
StepActionYe sNo
11. Evacuate the refrigerant system.
2. Charge the refrigerant.
Is there any refrigerant leak?
Repair refrigerant
system.
Go to Step 2
21. Operate the compressor for more than 5 minutes to raise the
pressure on the high pressure side.
Is there any refrigerant leak at high pressure components?
Repair refrigerant
system.
Compressor
operation to be
confirmed.
Inspection Steps
Check the components of air±conditioner to see if there
occurs any refrigerant leak along the flow of refrigerant.
NOTE:

To avoid refrigerant leak detection error, avoid
refrigerant vapor and cigarette smoke presence when
performing the inspection. Also, select a location that
is not susceptible to wind, in case refrigerant vapor is
found it will not be blown off.

Inspection should be conducted chiefly on the pipe
connections and sections where a marked oil
contamination is found. When refrigerant is leaking,
oil inside is also leaking at the same time.

It is possible to visually check the leak from inside the
cooling unit. Follow the method below when
performing the inspection. Remove the drain hose or
resistor of the cooling unit, and insert a leak detector
to see if there are signs of leakage.
High Pressure Side
1. Discharger section of compressor.
2. Inlet/outlet section of condenser.
3. Inlet/outlet section of receiver driver.
4. Inlet section of cooling unit.
Low Pressure Side
1. Outlet section of cooling unit.
2. Intake section of compressor.
Major Checking Points of Refrigerant Leak
Compressor

Pipe connection

Sealing section of shaft

Mating section or cylinder
Condenser

Pipe connection

Welds of condenser bodyReceiver driver

Pipe connection

Attaching section of pressure switch

Section around the sight glass
Evaporator unit (cooling unit)

Pipe connections

Connections of expansion valve

Brazed sections of evaporator
NOTE:

The evaporator and expansion valve are contained in
the case. Remove the drain hose or the resistor of the
cooling unit and insert a leak detector when checking
for any leak.
Flexible hose

Pipe connection

Caulking section of the hose

Hose (cracks, pinholes, flaws)
Pipe

Pipe connection

Pipe (cracks, flaws)
Charge valve
NOTE:

The charge valve, which is used to connect the gauge
manifold, is normally provided with a resin cap. When
the valve inside gets deteriorated, refrigerant will leak
out.Leak at Refrigerant Line Connections
1. Check the torque on the refrigerant line fitting and, if
too loose, tighten to the specified torque.

Use two wrenches to prevent twisting and damage
to the line.

Do not over tighten.
2. Perform a leak test on the refrigerant line fitting.

1A±34
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
3. If the leak is still present, discharge and recover the
refrigerant from the system.
4. Replace the O-rings.

O-rings cannot be reused. Always replace with new
ones.

Be sure to apply the specified compressor oil to the
new O-rings.
5. Retighten the refrigerant line fitting to the specified
torque.

Use two wrenches to prevent twisting and damage
to the line.
6. Evacuate, charge and retest the system.
Leaks In The Hose
If the compressor inlet or outlet hose is leaking, the entire
hose must be replaced. The refrigerant hose must not be
cut or spliced for repair.
1. Locate the leak.
2. Discharge and recover the refrigerant.
3. Remove the hose assembly.

Cap the open connections at once.
4. Connect the new hose assembly.

Use two wrenches to prevent twisting or damage to
the hose fitting.

Tighten the hose fitting to the specified torque.
5. Evacuate, charge and test the system.
Compressor Leaks
If leaks are located around the compressor shaft seal or
shell, replace or repair the compressor.
Recovery, Recycling, Evacuation and
Charging of HFC-134a
Air conditioning systems contain HFC-134a. This is a
chemical mixture which requires special handling
procedures to avoid personal injury.

Always wear safety goggles and protective gloves.

Always work in a well-ventilated area. Do not weld or
steam clean on or near any vehicle-installed air
conditioning lines or components.

If HFC-134a should come in contact with any part of
the body, flush the exposed area with cold water and
immediately seek medical help.

If it is necessary to transport or carry any container of
HFC-134a in a vehicle, do not carry it in the
passenger compartment.

If it is necessary to fill a small HFC-134a container
from a large one, never fill the container completely.
Space should always be allowed above the liquid for
expansion.

HFC-134a and R-12 should never be mixed as their
compositions are not the same.

HFC-134a PAG oil tends to absorb moisture more
quickly than R-12 mineral oil and, therefore, should
be handled more carefully.

Keep HFC-134a containers stored below 40
C
(104
F).WARNING:

SHOULD HFC-134A CONTACT YOUR EYE(S),
CONSULT A DOCTOR IMMEDIATELY.

DO NOT RUB THE AFFECTED EYE(S). INSTEAD,
SPLASH QUANTITIES OF FRESH COLD WATER
OVER THE AFFECTED AREA TO GRADUALLY
RAISE THE TEMPERATURE OF THE
REFRIGERANT ABOVE THE FREEZING POINT.

OBTAIN PROPER MEDICAL TREATMENT AS
SOON AS POSSIBLE. SHOULD THE HFC-134A
TOUCH THE SKIN, THE INJURY MUST BE
TREATED THE SAME AS SKIN WHICH HAS BEEN
FROSTBITTEN OR FROZEN.
Refrigerant Recovery
The refrigerant must be discharged and recovered by
using the J-39500 (ACR4:HFC-134a Refrigerant
Recovery/Recycling/Recharging/System) or equivalent
before removing or mounting air conditioning parts.
1. Connect the high and low charging hoses of the
ACR
4(or equivalent) as shown below.
901R100022
Legend
(1) Low Side
(2) High Side
2. Recover the refrigerant by following the
Manufacturer's Instructions.
3. When a part is removed, put a cap or a plug on the
connecting portion so that dust, dirt or moisture
cannot get into it.