1998-2003 Suzuki Alto 4 Door Air Conditioning (Optional) -> Diagnosis User Manual
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Air Conditioning (Optional) -> Diagnosis for Your Suzuki Alto 4 Door Fifth Generation (1998-2003)

1B-4 AIR CONDITIONING (OPTIONAL)
DIAGNOSIS
GENERAL DIAGNOSIS TABLE
Condition Possible Cause Correction
Cool air won’t come out
(A/C system won’t
operative)
D No refrigerant
D Fuse blown
D A/C switch faulty
D Blower fan switch faulty
D A/C thermistor faulty
D Dual pressure switch faulty
D Wiring or grounding faulty
D ECT sensor faulty
D ECM and its circuit faulty
Recover, evacuation and charging.
Check “HEATER” fuse and check short
circuit to ground.
Check A/C switch.
Check blower fan switch.
Check A/C thermistor.
Check dual pressure switch.
Repair as necessary.
Check ECT sensor.
Check ECM and its circuit.
Cool air won’t come out
(Compressor won’t
operative (won’t rotative))
D Fuse blown
D Compressor relay faulty
D ECM faulty
D Magnet clutch faulty
D Drive belt loosen or broken
D Compressor faulty
Check “A/C” fuse and check short
circuit to ground.
Check compressor relay.
Check magnet clutch.
Adjust or replace drive belt.
Check compressor.
Cool air won’t come out
(Radiator (and condenser)
cooling fan motor won’t
operative)
D “RDTR” fuse blown
D Radiator (and condenser) cooling fan
relay faulty
D Wiring or grounding faulty
D Radiator fan relay signal faulty
D Radiator (and condenser) cooling fan
motor faulty
Replace fuse and check short circuit to
ground.
Check radiator cooling fan relay.
Repair as necessary.
Check radiator fan relay signal.
Check radiator cooling fan motor.
Cool air won’t come out
(Blower motor won’t
operative)
D Fuse blown
D Blower resistor faulty
D Blower fan switch faulty
D Wiring or grounding faulty
D Blower motor faulty
Check “HEATER” fuse main heater
fuse and check short circuit to ground.
Check blower resistor.
Check blower fan switch.
Repair as necessary.
Check blower motor.
AIR CONDITIONING (OPTIONAL) 1B-5
Condition Possible Cause Correction
Cool air won’t come out or
insufficient cooling (A/C
system normal operative)
D Insufficient or excessive charge of
refrigerant
D Condenser clogged
D Evaporator clogged or frosted
D A/C thermistor faulty
D Expansion valve faulty
D Receiver/dryer clogged
D Drive belt slipping
D Magnetic clutch faulty
D Compressor faulty
D Air in A/C system
D Air leaking from cooling unit or air duct
D Heater and ventilation system faulty
D Blower motor faulty
D Excessive compressor oil existing in
A/C system
Check charge of refrigerant.
Check system for leaks.
Check condenser.
Check evaporator and A/C thermistor.
Check A/C thermistor.
Check expansion valve.
Check receiver/dryer.
Check or replace drive belt.
Check magnetic clutch.
Check compressor.
Replace receiver/dryer, and
evacuation and charging.
Repair as necessary.
Check air inlet box.
Check heater control lever assembly.
Check heater unit.
Check blower motor.
Pull out compressor oil in A/C system
circuit, and replace compressor.
Cool air won’t come out
only intermittently
D Wiring connection faulty
D Expansion valve faulty
D Excessive moisture in A/C system
D Magnetic clutch faulty
D Excessive charge of refrigerant
Repair as necessary.
Check expansion valve.
Replace receiver/dryer, and
evacuation and charging.
Check magnetic clutch.
Check charge of refrigerant.
Cool air comes out only at
high speeds
D Condenser clogged
D Insufficient charge of refrigerant
D Air in A/C system
D Drive belt slipping
D Compressor faulty
Check condenser.
Check charge of refrigerant.
Replace receiver/dryer, and
evacuation and charging.
Check or replace drive belt.
Check compressor.
Cool air won’t come out
only at high speeds
D Excessive charge of refrigerant
D Evaporator frosted
Check charge refrigerant.
Check evaporator.
Check A/C thermistor.
Insufficient velocity of
cooled air
D Evaporator clogged or frosted
D Air leaking from cooling unit or air duct
D Blower motor faulty
D Wiring or grounding faulty
Check evaporator.
Check A/C thermistor.
Repair as necessary.
Check blower motor.
Repair as necessary.
QUICKLY CHECKING OF REFRIGERANT
CHARGE
CHARGE OF REFRIGERANT
The following procedure can be used for quickly checking whether
the A/C system has a proper charge of refrigerant or not.
Run engine at fast idle, and operate A/C at its max. cooling capacity
for a few minutes. Then, look at the sight glass (1) on receiver/dryer
(2) and compare what is observed with the symptoms listed in
“CHECKING REFRIGERANT CHARGE” table given below.
3. Bubbles
1B-6 AIR CONDITIONING (OPTIONAL)
CHECKING REFRIGERANT CHARGE
Item
No.
Symptom Charge of refrigerant Correction
1 Bubbles observed in sight glass Insufficient charge of refrigerant
in system
Check system for leaks with a
leak tester.
2 No bubbles observed in sight glass No or insufficient charge of
refrigerant in system
Refer to the items 3 and 4.
3 No temperature difference between
compressor inlet and outlet
Empty or nearly empty system Evacuate and charge system
and then check it for leaks with
a leak tester.
4 Noticeable temperature difference
between compressor inlet and
outlet
Proper or too much charge of
refrigerant in system
Refer to the items 5 and 6.
5 When A/C is turned OFF,
refrigerant in sight glass clears
immediately and remains clear
Too much charge of refrigerant
in system
Discharge excess charge of re-
frigerant to adjust it to a speci-
fied charge.
6 When A/C is turned OFF,
refrigerant in sight glass once
produces bubbles and then clears
Proper charge of refrigerant in
system
NO CORRECTION NEEDED
BECAUSE CHARGE OF RE-
FRIGERANT IS NORMAL.
DIAGNOSIS TEST
1) Confirm that vehicle and environmental conditions are as fol-
lows.
– Vehicle is not exposed to direct sun.
– Ambient temperature is within 15 5C – 35 5C (59 5F – 95 5F).
2) Make sure that high pressure valve (1) and low pressure valve
(2) of manifold gauge are firmly closed.
3) Connect high pressure charging hose (3) to high pressure ser-
vice valve (5) on vehicle, and connect low pressure charging
hose (4) to low pressure service valve (6) on vehicle.
4) Bleed the air in charging hoses (3), (4) by loosening their re-
spective nuts on manifold gauge, utilizing the refrigerant pres-
sure. When a hiss is heard, immediately tighten nut.
5) Warm up engine to normal operating temperature (engine cool-
ant temperature at 80 – 90_C, 176 – 194_F) and keep it at speci-
fied idle speed.
6) Turn A/C switch ON, and set blower switch at “HI” (3rd position),
temperature knob at “COOL”, air outlet control knob at “FACE”,
fresh/circulation control knob at “CIRCULATION”. (Confirm that
A/C compressor and condenser fan are working.)
7) Keep all windows, doors and engine food open.
CAUTION:
Do not interchange high and low pressure charging
hoses by mistake.
8) With about 20 mm (0.8 in.) of dry bulb thermometer (1) inserted
into center duct air outlet and another one set near evaporator
air inlet, read temperature indicated on each thermometer.
AIR CONDITIONING (OPTIONAL) 1B-7
A/C inlet air temperature 15 – 355C (59 – 955F)
Engine rpm Keep to 1,500 rpm.
Blower fan motor switch Max. (3rd position)
Temperature control Max. cool
Air outlet control Face
Doors All open
Air inlet damper position Recirculation
9) Check for each pressure of low side and high side if it is within
shaded range of left graph.
NOTE:
Pressure registered on gauge varies with ambient tem-
perature. Therefore, use left graphs when determining if
pressures are normal or not.
Example:
If each gauge reading is out of specified pressure, correct de-
fective part referring to following Diagnosis Test table.
10) Check inlet port temperature-to-outlet port temperature rela-
tionship using graph at the left.
For example, if evaporator inlet port temperature is 25 5C (77
5F) and center duct air outlet temperature is 8 5C (46.4 5F),
their crossing point is within acceptable range as shown in
graph at the left.
11) If crossing point is out of acceptable range, diagnose trouble
referring to following Diagnosis Test table.
1B-8 AIR CONDITIONING (OPTIONAL)
Gauges should read as follows when ambient tempera-
ture is 30 5C.
Pressure on high pressure
gauge (HI):
1.18 – 1.47 MPa
12.0 – 15.0 kg/cm
2
Pressure on high pressure
gauge (LO):
0.2 – 0.3 MPa
2.0 – 3.0 kg/cm
2
AIR CONDITIONING (OPTIONAL) 1B-9
DIAGNOSIS TEST TABLE
TESTING RESULTS POSSIBLE CAUSE REMEDY
E
SSURE GAUGE
Pressure high
(“A” area of high side
graph)
D Refrigerant overcharged
D Expansion valve frozen or clogged
D Clogged refrigerant passage of high side
D Condenser fan malfunction Insufficient
cooling of
D Dirty or bent condenser fins condenser
D Compressor malfunction (Insufficient oil etc.)
D Engine overheat
D Recharge
D Check expansion valve
D Clean or replace
D Check condenser fan
D Clean or repair
D Check compressor
D Check engine cooling
system
HIGH PR
E
Pressure low
(“B” area of high side
graph)
D Insufficient refrigerant (Insufficient charge or
leakage)
D Expansion valve malfunction (valve opens too
wide)
D Compressor malfunction (Insufficient
compression)
D Check for leakage, repair if
necessary and recharge
D Check expansion valve
D Check compressor
E GAUGE
Pressure high
(“A” area of low side
graph)
D Expansion valve malfunction (valve opens too
wide)
D Compressor malfunction (Insufficient
compression)
D Check expansion valve
D Check compressor
LOW PRESSUR
E
Pressure low
(“B” area of low side
graph)
D Insufficient refrigerant (Insufficient charge or
leakage)
D Expansion valve malfunction (valve opens too
narrow)
D Clogged refrigerant passage (crashed pipe)
D Check for leakage, repair if
necessary and recharge
D Check expansion valve
D Repair or replace
M
OMETER AT
T
ER DUCT
Outlet air temperature
at center duct is high
(Crossing point is in
area “A”)
D Insufficient or excessive charge of refrigerant
D Dirty or bent evaporator fins
D Air leakage from cooling (heater) unit or air duct
D Malfunctioning, switchover function of damper
in cooling (heater) unit
D Compressor malfunction
D Check refrigerant pressure
D Clean or repair
D Repair or replace
D Repair or replace
D Check compressor
THERM
CEN
T
Outlet air temperature
at center duct is low
(Crossing point is in
area “B”)
D Insufficient air volume from center duct (Heater
blower malfunction)
D Compressor malfunction
D Check blower motor and
fan
D Check compressor
If ambient temperature is within 30 – 35 5C (86 – 95 5F), it is possible to do using next page table for detail diagnosis.
1B-10 AIR CONDITIONING (OPTIONAL)
DETAIL DIAGNOSIS TABLE AT AMBIENT TEMPERATURE WITHIN 30 – 35 5C (85 – 95 5F)
MPa
MANIFOLD kg/cm
2
GAUGE psi
CONDITION CAUSE CORRECTION
Lo Hi
0.2 – 0.3
2.0 – 3.0
28.4 – 42.6
1.18 – 1.47
12.0 – 15.0
170 – 213
Normal condition.
Negative
pressure
0.5 – 0.6
5 – 6
71.2 – 85.3
D The low pressure side
reads a negative pressure,
and the high pressure side
reads an extremely low
pressure.
D Presence of frost around
tubing to and from receiver/
dryer and expansion valve.
D Dust particles or water
droplets are either stuck or
frozen inside expansion
valve, preventing the re-
frigerant from flowing.
D Gas leak from heat-sensi-
tizing tube is preventing
refrigerant flow.
D Clean expansion valve.
Replace it if it cannot be
cleaned.
D Replace receiver/dryer.
D Evacuate the A/C system
and recharge with fresh re-
frigerant.
D If heat-sensitizing tube is
defective, replace expan-
sion valve.
Normal:
0.2 – 0.3
2.0 – 3.0
28.4 – 42.6
Abnormal:
Negative
pressure
µ
Normal:
1.18 – 1.47
12.0 – 15.0
170 – 213
Abnormal:
0.69 – 0.98
7 – 10
99.4 – 142
µ
D During A/C operation, the
low pressure side some-
times indicates negative
pressure, and sometimes
normal pressure. Also
high pressure side reading
fluctuates between the ab-
normal and normal pres-
sure.
D Expansion valve is frozen
due to moisture in the sys-
tem, and temporarily shuts
off the
refrigeration cycle.
D Replace expansion valve.
D Replace receiver/dryer.
D Evacuate A/C system and
recharge with fresh
refrigerant.
0.05 – 0.1
0.5 – 1.0
7.1 – 14.2
0.69 – 0.98
7 – 10
100 – 142
D Both low and high
pressure sides indicate
low readings.
D Continuous air bubbles
are visible through sight
glass.
D Output air is slightly cold.
D Insufficient refrigerant in
system.
(Refrigerant leaking)
D Using a gas leak detector,
check for leaks and repair
as necessary.
D Recharge refrigerant to a
specified amount.
If the pressure reading is al-
most 0 when the
manifold gauges are
attached, check for any
leaks, repair them, and
evacuate the system.
0.4 – 0.6
4 – 6
56.9 – 85.3
D Pressure on low pressure
side is high.
D Pressure on high pressure
side is low.
D Both pressure becoming
equal right after A/C is
turned OFF.
D Internal leak in compres-
sor.
D Inspect compressor and re-
pair or replace as
necessary.
0.25 – 0.3
25 30
1.96 – 2.45
20 25
D High pressure reading on
both low and high
pressure sides.
D Air bubbles are not visible
even when engine rpm is
lowered.
D Overcharged A/C system.
D Faulty condenser
cooling operation.
D Faulty condenser fan op-
eration.
D Adjust refrigerant to
specified amount.
D Clean condenser.
D Inspect and repair
condenser fan.
2
.
5
–
3
.
0
35.6 – 42.6
20
–
25
285 – 355
D High pressure reading on
both low and high
pressure sides.
D Low pressure side tubing
is not cold when touched.
D Air bubbles are visible
through sight glass.
D Presence of air in A/C sys-
tem.
(Improperly evacuated)
D Replace receiver/dryer.
D Inspect quantity of com-
pressor oil and presence of
contaminants in oil.
D Evacuate system and
recharge with fresh
refrigerant.
0.3 – 0.4
3.0 – 4.0
42.7 – 56.8
1.86 – 1.96
19 – 20
271 – 284
D High pressure reading on
both low and high
pressure sides.
D Large amount of frost or
dew on the low pressure
side tubing.
D Faulty expansion valve or
improper attachment of
heat-sensitizing tube.
D Refrigerant flow is not regu-
lated properly.
D Inspect if heat-sensitizing
tube is properly attached.
D Replace expansion valve.
WIRING CIRCUIT
1. Blower fan motor
2. Blower fan motor resistor
3. Blower fan motor switch
4. Dual pressure switch
5. A/C Switch
6. Fuse box
7. Radiator (and condenser) cooling fan relay
8. Radiator (and condenser) cooling fan motor
9. Compressor
10. Main relay
11. Ignition switch
12. A/C evaporator thermistor
13. ECT sensor
14. Compressor relay
AIR CONDITIONING (OPTIONAL) 1B-11
A/C SYSTEM INSPECTION OF ECM AND ITS
CIRCUITS
ECM and its Circuits can be checked at ECM wiring couplers by
measuring voltage.
CAUTION:
ECM cannot be checked by itself. It is strictly prohibited
to connect voltmeter or ohmmeter to ECM with couplers
disconnected from it.
Fig. A
Fig. B
Voltage Check
1) Remove ECM from vehicle.
2) Connect ECM couplers (2) to ECM (1).
3) Check voltage at each terminal of couplers connected.
Refer to “Inspection of ECM and its circuit” in ENGINE AND
EMISSION CONTROL SYSTEM section.
NOTE:
As each terminal voltage is affected by the battery voltage,
confirm that it is 11V or more when ignition switch is ON.
TERMINAL ARRANGEMENT OF ECM COUPLER (VIEWED FROM HARNESS SIDE)
1. Blower fan motor
2. ECM
3. Dual pressure switch
4. A/C switch
5. A/C evaporator thermistor
6. ECT sensor
7. Radiator fan relay
8. Radiator fan
9. Compressor
10. Main relay
11. Engine earth
12. Blower fan motor switch
13. Compressor relay
A. To HTR fuse 15A
B. To A/C fuse 10A
C. To RDTR fuse 30A
D. To IG fuse 15A
E. To FI fuse 15A
1B-12 AIR CONDITIONING (OPTIONAL)
AIR CONDITIONING (OPTIONAL) 1B-13
ECM VOLTAGE VALUES TABLE FOR RELATION OF A/C CONTROL
Terminal Wire Circuit
Measurement
ground
Normal value Condition
E32-301 B ECM main ground
Ground to
body (Fig A)
–0.4 – 0 volt Engine running
E32-302 B/R
Main power supply
for ECM
Ground to
engine (Fig B)
10 – 14 volts
Ignition switch ON with engine
stopped
E32-313 Bl/B
ECM ground for
power circuit
Ground to
body (Fig A)
–0.4 – 0 volt Engine running
E32-315 B/R
Power supply for
ECM power circuit
Ground to
engine (Fig B)
10 – 14 volts
Ignition switch ON with engine
stopped
E32-319 V/R Main relay drive
Ground to
0.5 – 1.2 volt
Ignition switch ON with engine
stopped
0 volt Ignition switch OFF
E32-320 Bl
Radiator (condens-
er) cooling fan relay
out
p
ut
Ground to
engine (Fig B)
0 – 1 volt
Blower fan motor switch and A/C
switch ON or engine coolant temp
sensor more than 100 5C (212 5F)
with engine running
out ut
10 – 14 volts
Except the above-mentioned with
engine running
E32-326 Bl/B
ECM ground for
power circuit
Ground to
body (Fig A)
–0.4 – 0 volt Engine running
E34-09
P/B
Blower load for Ground to
0 – 1 volt
Blower fan motor switch ON with en-
gine running
E34
-
09
P/B
blower fan input engine (Fig B)
10 – 14 volts
Blower fan motor switch OFF with
engine running
E34-19
Or/B
A/C switch in
p
ut
Ground to
0 – 1 volts
Blower fan motor switch and A/C
switch ON with engine running
E34
-
19
Or/B
A/C
switch
in ut
engine (Fig B)
10 – 14 volt
Blower fan motor switch or A/C
switch OFF with engine running
E34-22 B/G
Sensor common
ground
Ground to
body (Fig A)
–0.4 – 0 volt Engine running
E33-207
V/R
Evaporator thermis-
tor temperature
Ground to
2.0 – 2.5 volts
(2100 – 2580 W)
Evaporator thermistor temperature at
approx. 15 5C (59 5F) with engine
running
E33
-
207
V/R
(EVAP temp sen-
sor) input
engine (Fig B)
3.1 – 3.3 volts
(4600 – 5100 W)
Evaporator thermistor temperature at
approx. 0 5C (32 5F) with engine
running
E33-208
Lg/B
Engine coolant
tem
p
erature sensor
Ground to
0.71 – 0.76 volts
(290 – 320 W)
Engine coolant temperature at
approx. 80 5C (176 5F) with engine
running
E33
-
208
Lg/B
tem erature
sensor
input
engine (Fig B)
0.35 – 0.37 volts
(136 – 144 W)
Engine coolant temperature at
approx. 110 5C (230 5F) with engine
running
E33-216
P/B
Compressor mag-
net clutch relay
Ground to
0 – 1 volt
Blower fan motor switch and A/C
switch ON with engine running
E33
-
216
P/B
net
clutch
relay
output
engine (Fig B)
10 – 14 volts
Except the above-mentioned with
engine running
A/C COMPRESSOR DRIVE BELT INSPEC-
TION
1) Check belt for wear and cracks, and replace as required.
2) Check belt tension by measuring how much it deflects when
pushed at intermediate point between compressor pulley (1)
and crankshaft pulley (2) with about 100 N (10 kg, 22 lbs) force.
“a” : 7 – 9 mm (0.27 – 0.35 in.) as deflection/100N
(10 kg, 22 lbs)
If belt tension is without above specification, adjust belt tension
by according to following items.
i) Loosen mounting bolts (1) and adjust bolt (2).
ii) Adjust belt tension rotated compressor (3) by using a wood
bar.
iii) Tighten adjust bolt (2) and mounting bolt (1) as rotated com-
pressor.
iv) Turn the crank pulley one revolution, then check belt tension.
1B-14 AIR CONDITIONING (OPTIONAL)

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