NISSAN LATIO 2007 Service Repair Manual

TROUBLE DIAGNOSIS
MTC-49
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23. CHECK CIRCUIT CONTINUITY BETWEEN DEFROST A/C SWITCH AND BCM
1. Disconnect defrost A/C switch connector.
2. Check continuity between BCM harness connector M18 (B) ter-
minal 10 and defrost A/C switch harness connector M41 (A) ter-
minal 15.
OK or NG
OK >> GO TO 24.
NG >> Repair harness or connector.
24. CHECK CIRCUIT CONTINUITY BETWEEN DEFROST A/C SWITCH AND GROUND
Check continuity between A/C defrost switch harness connector
M41 terminal 16 and ground.
OK or NG
OK >> Replace defrost A/C switch.
NG >> Repair harness or connector.10 - 15 :Continuity should exist
WJIA2254E
16 - Ground :Continuity should exist
WJIA2255E

MTC-50
TROUBLE DIAGNOSIS
Revision: June 20062007 Versa
Insufficient CoolingEJS0057P
SYMPTOM: Insufficient cooling
INSPECTION FLOW
1. CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE DECREASE
1. Turn temperature control dial counterclockwise to maximum cold position.
2. Check for cold air at discharge air outlets.
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2. CHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to MTC-33, "
Operational Check" .
Does another symptom exist?
YES >> Refer to MTC-24, "SYMPTOM TABLE" .
NO >> System OK.
3. CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4. CHECK COMPRESSOR DRIVE BELT TENSION
Check compressor belt tension. Refer to EM-13, "
Checking Drive Belts" .
OK or NG
OK >> GO TO 5.
NG >> Adjust or replace compressor belt. Refer to EM-13, "
Removal and Installation" .
5. CHECK AIR MIX DOOR CABLE
Check and verify air mix door cable operation. Refer to MTC-70, "
Air Mix Door Cable Adjustment" .
Does air mix door operate correctly?
YES >> GO TO 6.
NO >> Repair or replace as necessary.
6. CHECK COOLING FAN MOTOR OPERATION
Check and verify cooling fan motor for smooth operation. Refer to EC-443, "
System Description" .
Does cooling fan motor operate correctly?
YES >> GO TO 7.
NO >> Check cooling fan motor. Refer to EC-443, "
DTC P1217 ENGINE OVER TEMPERATURE" .
7. CHECK FOR EVAPORATOR FREEZE UP
Start engine and run A/C. Check for evaporator freeze up.
Does evaporator freeze up?
YES >> Perform performance test diagnoses. Refer to MTC-52, "PERFORMANCE TEST DIAGNOSIS" .
NO >> GO TO 8.

TROUBLE DIAGNOSIS
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8. CHECK REFRIGERANT PRESSURE
Check refrigerant pressure with manifold gauge connected. Refer to MTC-54, "
Test Reading" .
OK or NG
OK >> GO TO 9.
NG >> Perform performance test diagnoses. Refer to MTC-52, "
PERFORMANCE TEST DIAGNOSIS" .
9. CHECK AIR DUCTS
Check ducts for air leaks.
OK or NG
OK >> If the symptom still exists, perform a complete operational check. Refer to MTC-33, "Operational
Check" . If other symptoms exist, refer to MTC-24, "SYMPTOM TABLE" .
NG >> Repair air leaks.

MTC-52
TROUBLE DIAGNOSIS
Revision: June 20062007 Versa
PERFORMANCE TEST DIAGNOSIS
*1MTC-54, "PERFORMANCE CHART"*2MTC-54, "Te s t R e a d i n g"*3MTC-55, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"
*4MTC-70, "Air Mix Door Cable Adjust-
ment"
RJIA1601E

TROUBLE DIAGNOSIS
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*1MTC-85, "INSPECTION FOR
CLUTCH DISC TO PULLEY CLEAR-
ANCE"
*2MTC-37, "Blower Motor Circuit"*3EM-13, "Checking Drive Belts"
RJIA3107E

MTC-54
TROUBLE DIAGNOSIS
Revision: June 20062007 Versa
PERFORMANCE CHART
Test Condition
Testing must be performed as follows:
Test Reading
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to-operating Pressure Table
*1: With blower control dial in the "1" position
*2: With blower control dial in the "4" position.
Vehicle condition Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door window Open
Hood Open
TEMP. Max. COLD
Mode control dial
(Ventilation) set
Intake door lever
(Recirculation) set
Blower speedMax. speed set
Engine speed Idle speed
Operate the air conditioning system for 10 minutes before taking measurements.
Inside air (Recirculating air) at blower assembly inlet
Discharge air temperature at center ventilator
°C (°F) Relative humidity
%Air temperature
°C (°F)
50 - 6020 (68) 7.2 - 9.1 (45 - 48)
25 (77) 11.4 - 13.8 (53 - 57)
30 (86) 15.5 - 18.4 (60 - 65)
35 (95) 20.3 - 23.7 (69 - 75)
60 - 7020 (68) 9.1 - 10.9 (48 - 52)
25 (77) 13.8 - 16.2 (57 - 61)
30 (86) 18.4 - 21.3 (65 - 70)
35 (95) 23.7 - 27.1 (75 - 81)
Ambient air
High-pressure (Discharge side)
kPa (bar, kg/cm
2 , psi)Low-pressure (Suction side)
kPa (bar, kg/cm2 , psi) Relative humidity
%Air temperature
°C (°F)
50 - 7020 (68)843 - 1,036 *1
(11.08 - 13.63, 8.6 - 10.6, 122 - 150)159.0 - 194.0
(1.59 - 1.94, 1.62 - 1.98, 23.1 - 28.1)
25 (77)1,094 - 1,338 *1
(10.94 - 13.38, 11.2 - 13.6, 159 - 194)196.3 - 240.0
(1.96 - 2.40, 2.00 - 2.45, 28.5 - 34.8)
30 (86)1,298 - 1,590 *1
(12.98 - 15.90, 13.2 - 16.2, 188 - 231)248.0 - 302.7
(2.48 - 3.03, 2.53 - 3.09, 36.0 - 43.9)
35 (95)1,383 - 1,688 *2
(13.83 - 16.88, 14.1 - 17.2, 201 - 245)308.8 - 377.4
(3.09 - 3.77, 3.15 - 3.85, 44.8 - 54.7)
40 (104)1,628 - 1,988 *2
(16.28 - 19.88, 16.6 - 20.3, 236 - 288)377.4 - 461.2
(3.77 - 4.61, 3.85 - 4.70, 54.7 - 66.8)

TROUBLE DIAGNOSIS
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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
condenser.Excessive refrigerant charge in
refrigeration cycle.Reduce refrigerant until
specified pressure is
obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cooling perfor-
mance.
↓
1. Condenser fins are clogged.
2. Improper fan rotation of cooling
fan.

Clean condenser.

Check and repair cooling
fan if 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
gradually thereafter.Poor heat exchange in condenser
(After compressor operation stops,
high-pressure decreases too
slowly.).
↓
Air in refrigeration cycle.Evacuate repeatedly and
recharge system.
Engine tends to overheat. Engine cooling systems malfunction.Check and repair each
engine cooling system.

An area of the low-pres-
sure 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 discharge
flow.

Expansion valve is open a little
compared with the specification.
↓
Improper expansion valve adjust-
ment.Replace 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 oil for contami-
nation.
AC360A

MTC-56
TROUBLE DIAGNOSIS
Revision: June 20062007 Versa
High-pressure Side is Too Low and Low-pressure Side is Too High
Both High- and Low-pressure Sides are Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low
and low-pressure side is too
high.High- and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure operation
is improper.
↓
Damaged inside compressor
packings.Replace compressor.
No temperature difference
between high- and low-pres-
sure sides.Compressor pressure operation
is improper.
↓
Damaged inside compressor
packings.Replace compressor.
AC356A
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure
sides are too low.

There is a big temperature
difference between liquid tank
outlet and inlet. Outlet tem-
perature is extremely low.

Liquid tank inlet and expan-
sion valve are frosted.Liquid tank inside is slightly
clogged.

Replace liquid tank.

Check oil for contamination.

Temperature of expansion
valve inlet is extremely low as
compared with areas near liq-
uid tank.

Expansion valve inlet may be
frosted.

Temperature difference
occurs somewhere in high-
pressure side.High-pressure pipe located
between liquid tank and expan-
sion valve is clogged.

Check and repair malfunc-
tioning parts.

Check oil for contamination.
Expansion valve and liquid tank
are warm or only cool when
touched.Low refrigerant charge.
↓
Leaking fittings or componentsCheck refrigerant for leaks.
Refer to MTC-92, "
Checking
for Refrigerant Leaks" .
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.
↓
1. Improper expansion valve
adjustment.
2. Malfunctioning expansion
valve.
3. Outlet and inlet may be
clogged.

Remove foreign particles by
using compressed air.

Replace expansion valve.

Check oil for contamination.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.Low-pressure pipe is clogged or
crushed.

Check and repair malfunc-
tioning parts.

Check oil for contamination.
Air flow volume is not enough or
is too low.Evaporator is frozen.

Check thermo control amp.
Refer to MTC-41, "
Magnet
Clutch Circuit (If Equipped)"
.

Replace compressor.

Repair evaporator fins.

Replace evaporator.

Refer to MTC-37, "Blower
Motor Circuit" .
AC353A

TROUBLE DIAGNOSIS
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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 oil for contamination.
AC362A

MTC-58
TROUBLE DIAGNOSIS
Revision: June 20062007 Versa
Insufficient HeatingEJS0057Q
SYMPTOM: Insufficient heating
INSPECTION FLOW
1. CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE DECREASE
1. Turn temperature control dial clockwise to maximum heat position.
2. Check for hot air at discharge air outlets.
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2. CHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to MTC-33, "
Operational Check" .
Does another symptom exist?
YES >> Refer to MTC-24, "SYMPTOM TABLE" .
NO >> System OK.
3. CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4. CHECK COOLANT SYSTEM
1. Check engine coolant level. Refer to CO-8, "
ENGINE COOLANT" .
2. Check hoses for leaks or kinks.
3. Check Radiator cap. Refer to CO-13, "
Checking Radiator Cap" .
OK or NG
OK >> GO TO 5.
NG >> Repair/replace as necessary.
5. CHECK AIR MIX DOOR CABLE
Check air mix door cable operation. Refer to MTC-70, "
Air Mix Door Cable Adjustment" .
OK or NG
YES >> GO TO 6.
NO >> Adjust or replace air mix door cable. Refer to MTC-70, "
Air Mix Door Cable Adjustment" .
6. CHECK AIR DUCTS
Check ducts for air leaks.
OK or NG
OK >> GO TO 7.
NG >> Repair air leaks.
7. CHECK HEATER HOSE TEMPERATURES
1. Start engine and warm it up to normal operating temperature.
2. Touch both the inlet and outlet heater hoses.
Is the inlet hose hot and the outlet hose warm? YES or NO
YES >> GO TO 8.
NO >> Both hoses warm: GO TO 9.