2002 NISSAN TERRANO Service Repair Manual

TROUBLE DIAGNOSES FOR ABNORMAL PRESSURE
Whenever abnormal pressure of high and/or low sides of the system is noted, diagnosis must be conducted
by using a manifold gauge. The large-line zone on the gauge scale (see illustrations.) shown in the following
table refers to the standard (normal) pressure range for the corresponding pressure side (high or low). Since
the standard (normal) pressure, however, differs from vehicle to vehicle, refer to the ªAmbient air temperature-
to-compressor pressure tableº.
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure
sides are too high.
AC359A
IPressure is reduced soon
after water is splashed on
condenser.Excessive refrigerant charge in
refrigeration cycleReduce refrigerant until speci-
fied pressure is obtained.
Air suction by radiator or con-
denser fan is insufficient.Insufficient condenser cooling
performance
"
q
1Condenser fins are clogged.
q
2Improper rotation of radiator
fan or condenser fanIClean condenser.
ICheck and repair radiator or
condenser fan as necessary.
ILow-pressure pipe is not
cold.
IWhen compressor is stopped
high-pressure value quickly
drops by approximately 196
kPa (2 kg/cm
2, 28 psi). It
then decreases gradually
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.
IAreas near low-pressure
pipe connection and service
valves are considerably cold
compared with areas near
expansion valve outlet or
evaporator.
IPlates are sometimes cov-
ered with frost.IExcessive liquid refrigerant
on low-pressure side
IExcessive refrigerant dis-
charge flow
IExpansion valve is open a
little compared with the
specification.
"
q
1Improper thermal valve
installation
q
2Improper expansion valve
adjustmentReplace expansion valve.
DIAGNOSES Ð Overall System
Performance Test Diagnoses (Cont'd)
HA-32

Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high
and low-pressure side is too low.
AC360A
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.ICheck and repair or replace
malfunctioning parts.
ICheck compressor oil for
contamination.
High-pressure side is too low
and low-pressure side is too
high.
AC356A
High- and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure opera-
tion is improper.
"
Damages inside compressor
packingsReplace compressor.
No temperature difference
between high- and low-pres-
sure sidesCompressor discharge capac-
ity does not change. (Com-
pressor stroke is set at maxi-
mum.)Replace compressor.
Both high- and low-pressure
sides are too low.
AC353A
IThere is a big temperature
difference between liquid
tank outlet and inlet. Outlet
temperature is extremely
low.
ILiquid tank inlet and expan-
sion valve are frosted.Liquid tank inside is clogged a
little.IReplace liquid tank
ICheck compressor oil for
contamination.
ITemperature of expansion
valve inlet is extremely low
as compared with areas near
liquid tank.
IExpansion valve inlet may
be frosted.
ITemperature difference
occurs somewhere in high-
pressure sideHigh-pressure pipe located
between liquid tank and
expansion valve is clogged.ICheck and repair malfunc-
tioning parts.
ICheck compressor oil for
contamination.
DIAGNOSES Ð Overall System
Performance Test Diagnoses (Cont'd)
HA-33

Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure
sides are too low.
AC353A
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.
"
q
1Improper expansion valve
adjustment
q
2Malfunctioning thermal valve
q
3Outlet and inlet may be
clogged.IRemove foreign particles by
using compressed air.
ICheck compressor oil for
contamination.
Areas near low-pressure pipe
connection and service valve
are extremely cold as com-
pared with areas near expan-
sion valve outlet and evapora-
tor.Low-pressure pipe is clogged
or crushed.ICheck and repair malfunc-
tioning parts.
ICheck compressor oil for
contamination.
Air flow volume is not enough
or is too low.Evaporator is frozen.
"
Compressor discharge capac-
ity does not change. (Com-
pressor stroke is set at maxi-
mum length.)Replace compressor.
Low-pressure side sometimes
becomes negative.
AC354A
IAir conditioning system does
not function and does not
cyclically cool the compart-
ment air.
IThe system constantly func-
tions for a certain period of
time after compressor is
stopped and restarted.Refrigerant does not discharge
cyclically.
"
Moisture is frozen at expan-
sion valve outlet and inlet.
"
Water is mixed with refrigerant.IDrain water from refrigerant
or replace refrigerant.
IReplace liquid tank.
DIAGNOSES Ð Overall System
Performance Test Diagnoses (Cont'd)
HA-34

Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes
negative.
AC362A
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.After the system is left at rest,
start it again in order to con-
firm whether or not problem is
caused by water or foreign
particles.
IIf the problem is due to
water, drain water from
refrigerant or replace refrig-
erant.
IIf it is due to foreign
particles, remove expansion
valve and remove them with
dry and compressed air.
IIf either of the above meth-
ods cannot correct the
problem, replace expansion
valve.
IReplace liquid tank.
ICheck compressor oil for
contamination.
DIAGNOSES Ð Overall System
Performance Test Diagnoses (Cont'd)
HA-35

Symptom Chart
DIAGNOSTIC TABLE
PROCEDUREPrelimi-
nary
CheckDiagnostic
ProcedureMain Power
Supply and
Ground Circuit
CheckElectrical Components Inspection
SYMPTOM
Preliminary check 1
Preliminary check 2
Diagnostic procedure 1
Diagnostic procedure 2
Diagnostic procedure 3
15A Fuses
10A Fuse
15A Fuse
Blower motor
Intake door motor
Resistor
A/C switch
Fan switch
A/C relay
Dual-pressure switch
Compressor
Harness Magnet clutch
A/C does not blow cold air.q qqqq qqqqqqq
Blower motor does not rotate.
qqqqq q
Magnet clutch does not
engage when A/C switch and
fan switch are ON.
qq qqqqqq
Noise
Intake door does not change.qq q
,: The number indicates checking order.
q: Refer to each flow chart for checking order. (It depends on malfunctioning portion.)
TROUBLE DIAGNOSES
HA-36

Preliminary Check
PRELIMINARY CHECK 1
A/C does not blow cold air.
DOES AIR FLOW FROM VENTS?
Condition
IIgnition switch, A/C switch, and
fan switch are ON.
IMode lever is in VENT mode
and temperature lever is in full
cold position.
OK
ENG
IS BLOWER MOTOR OPERAT-
ING NORMALLY?
Ye s N o
CHECK
BLOWER
MOTOR
OPERATION.
Go toDiagnos-
tic Procedure
1.
CHECK COMPRESSOR BELT TEN-
SION.
Refer to MA section.
NG OK
ENG
CHECK COMPRESSOR OPERA-
TION.
OKCHECK FOR EVAPORATOR COIL
FREEZE UP.
Remove intake unit. Check if
evaporator freezes.
NG
(Freezes up)OK
(Does not
freeze up)
Adjust or
replace com-
pressor belt.
CHECK REFRIGERATION CYCLE
PRESSURE WITH RECOVERY/
RECYCLING EQUIPMENT CON-
NECTED.
Refer to Performance Chart.
NG OKCHECK VENTI-
LATOR DUCT
FOR AIR
LEAKS.
CHECK AMOUNT OF
REFRIGERANT.
Check amount of refrigerant using
ACR4 (Refrigerant recovery &
recharging equipment).
OK NGGo toPerfor-
mance Test
Diagnoses.
CHECK THERMO CONTROL
AMP. OPERATION.
Refer to Electrical Components
Inspection.
Evacuate sys-
tem and
recharge with
refrigerant.CHECK FOR
REFRIGERANT
LEAKS.
Go toDiagnostic Procedures 2.
CHECK AIR CONTROL CABLE
ADJUSTMENT.
Refer to Control Linkage Adjust-
ment.FOK
CHECK EVAPORATOR OUTLET
AIR TEMPERATURE.
Refer to Performance Chart.
NG
CHECK THERMO CONTROL
AMP. OPERATION.
Refer to Electrical Components
Inspection.
H
HH
HHH
HHH
HH
H
H
H
TROUBLE DIAGNOSES
HA-37

PRELIMINARY CHECK 2
Noise
Check where noise
comes from.
Expansion valveCompressorRefrigerant lineBelt
Replace expan-
sion valve.Replace com-
pressor.
The line is fixed directly
to the body.The line is not fixed.
Fix the line with rubber
or some vibration
absorbing material.Fix the line tightly.
The belt vibration is
intense.Side of belt is worn
out.
Readjust belt tension.
Refer to ENGINE MAIN-
TENANCE in MA sec-
tion.The pulley center
does not match.
Readjust the pulley
center.
HHHH
HH
HH
HH
HH
HH
TROUBLE DIAGNOSES
Preliminary Check (Cont'd)
HA-38

Harness Layout for A/C System
LH DRIVE MODELS
YHA404
TROUBLE DIAGNOSES
HA-39