1998 NISSAN GT-R cooling

TROUBLE DIAGNOSES .
CONSULT (Cont'd)
Monitored item
[Unit] signals Description
Remarks
INJ
PULSE [msec]
I
When the engine is stopped, a certain
computed value is indicated. lndicates the actual fuel injection pulse
width compensated by ECM according to
the input
siqnals.
IGN TIMING [BTDC]
I lo
lndicates the ignition timing computed by ECM according to the input signals. When the engine is stopped, a certain
value is indicated.
IACV-AACN
I%]
I lo
lndicates IACV-AACN control value com-
puted by ECM according to the input sig-
nals.
PURG VOL CN
[ONIOFF dutyj lndicates the EVAP canister purge vol-
ume control valve computed by the ECM according to the input signals. The opening becomes larger as the
value increases.
AIF
ALPHA [%]
- The mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated. -- - When the engine is stopped, a certain
value is indicated.
This data also includes the data for the
air-fuel ratio learning control.
AIR COND
RLY [ONIOFF] The air conditioner relay control condition
(determined by ECM according to the
input signal) is indicated.
-- - - Indicates the fuel pump relay control con-
dition determined by ECM according to
the input signals.
The control condition of the intake valve
timing control solenoid valve is indicated.
ON
... Intake valve timing control is oper-
ating. OFF
... lntake valve timing control is not
operating.
VlAS
SN [ONIOFF] RB20DE (UB), RB25DE
Control conditions computed by ECM Solenoid valve activated: ON Solenoid valve not activated: OFF
SWRL CONT SN
[ON/OFF]
0 RB20DE (UB)
COOLING FAN
[HVLOW/O FF] RB25DE, RB25DET
The control condition of the cooling fan
(determined by ECM according to the
input signal) is indicated.
HI
... High speed operation LOW ... Low speed operation
OFF ... Stop
TURBO CONT
SN 0 RB25DET Control conditions computed by ECM
Solenoid valve activated: ON Solenoid valve not activated: OFF
PD PRESSURE
SENSOR M Refrigerant pressure sensor output volt-
age Approx. 0.36V min.
(Varies with air conditioner refrigerant
pressure)
, VOLTAGE Voltage measured by the voltage probe.
Pulse width, frequency or duty cycle
measured by the pulse probe. Only "#" is displayed if item is unable to
be measured.
r Figures with "#"s are temporary ones.
They are the same figures as an actual
piece of data which was just previously
measured.

TROUBLE DIAGNOSES
CONSULT (Cont'd)
ACTIVE TEST MODE
INJECTION I . CCohArthe amount of fuel injection
TEST ITEM
CONDITION
Engine: Return
to the original trouble
- I . Engine: After warming up, idle the
IACV-AACN
OPENING
ENG COOLANT
TEMP
IGNITION TIMING
US~~~CONSULT.
Engine: After warming up, idle the
engine.
Change the IACV-AAC valve opening
percent using CONSULT.
Engine: Return to the original trouble
conditioo
Change the engine coolant
temperature using CONSULT.
Engine: Return to the original trouble
condition
Timing light: Set Retard the ignition timing using CONSULT.
POWER BALANCE engine. A/C switch "OFF . Shift lever uNn
COOLING
FAN RB25DE, RB25DET
FUEL PUMP RELAY
VlAS SOL VALVE RB20DE (UB), RB25DE
JUDGEMENT
Cut off each injector signal one at a
time using CONSULT.
Ignition switch: ON Turn the cooling fan "ON" and "OFF
using CONSULT.
0 lgnition switch: ON (Engine stopped) . Turn the fuel pump relay "ON" and
"OFF using CONSULT and listen to
operating sound. CHECK
ITEM (REMEDY)
If trouble symptom disappears, see
CHECK ITEM. : ~,"~~,,,~scOnnectOr Oxygen sensor
Engine speed changes according to the
opening percent.
. Harness and connector IACV-AAC valve
If trouble
symp:orn disappears, see
CHECK ITEM. : Sensor 0 Fuel injectors
If trouble symptom disappears, see
CHECK ITEM. 0 Adjust ignition timing (by moving
camshaft position sensor)
Engine runs rough or dies.
Harness and connector Compression Injectors 0 lgnition coil with power transistor Spark plugs
Cooling fan moves and stops.
Hamess and connector Cooling fan motor Cooling fan relay
Fuel pump relay makes the operating
sound.
. Harness and connector Fuel pump relay
VALVE
TIMING
SOL
SWIRL CONT SOL
VALVE
0 RB20DE (UB)
SELF-LEARNING
CONT
PURG VOL CONTN
Checks control items and output circuit by arbitrary ON/OFF operation.
. In this test, the coefficient of self-learning control mixture ratio returns to the original coefficient by touching "CLEAR" on the
screen.
. Harness and connector EVAP canister purge control solenoid
valve
Vacuum hose
0 Engine: Run engine at 2,000 rpm. . Turn the EV~P canister purge control solenoid valve and using CONSULT and listen for operating
sound. EVAP
canister purge control solenoid
valve makes an operating sound. Check
vacuum signal for EVAP canister purge ~~~~~~a'cuum exists. VC OFF ... Vacuum does not exist.

TROUBLE DIAGNOSES t i
CONSULT (Cont'd) i
FUNCTION TEST MODE
CHECK ITEM (REMEDY)
FUNCTION
TEST
ITEM JUDGEMENT
CONDITION
lgnition switch: ON
(Engine stopped)
Displays the results of on board
diagnostic system.
SELF-DIAG
RESULTS Objective
system
--
ignition switch: ON
(Engine stopped)
Throttle position sensor circuit is
tested when throttle is opened and
closed fully. ("IDLE POSITION" is
the test item name for the vehicles
in which idle is selected by throttle
position sensor.) Harness and connector
Throttle position sensor (Closed
throttle position)
Throttle position sensor (Closed
throttle position) adjustment
Throttle linkage
Venfy operation in DATA
MONITOR mode.
Throttle
valve:
opened OFF
ON
CLOSED THROTTLE
POSl Throttle valve:
closed
lgnition switch: ON
(Engine stopped)
Throttle position sensor circuit is
tested when throttle is opened and
closed fully.
Harness and connector
Throttle position sensor
Throttle position sensor
adjustment
Throttle linkage
Verify operation in DATA
MONITOR mode.
Range
(Throttle
valve fully opened
- Throttle valve
fully closed) More
than 3.0V THROTTLE POSl
SEN CKT
lgnition switch: ON
(Engine stopped)
Neutral position switch circuit is
tested when shift lever is
manipulated.
lgnition switch: ON
(Engine stopped)
Fuel pump circuit is tested by
checking the pulsation in fuel
pressure when fuel tube is
pinched. Out of
N/P
positions OFF
Harness
and connector
Neutral position switch
Linkage adjustment
PARWNEUT POSl SW CKT
In
N/P positions
Harness and connector
Fuel pump
Fuel pump relay
Fuel filter clogging
Fuel level
There
is pressure pulsation on
the fuel feed hose.
FUEL PUMP
CIRCUIT
--
The valve timing control system is
diagnosed by checking for
operating sound of the solenoid
valve.
lgnition switch: ON
(Engine stopped)
Cooling fan circuit is tested when
cooling fan is rotated.
VALVE
TIMING
SN
CKT
Harness and connector
Cooling fan motor
Cooling fan relay
COOLING
FAN
CIRCUIT RB25DE, RB25DET
The cooling fan rotates and
stops every
3 seconds.
lgnition switch: ON -+ START
Start signal circuit is tested when
engine is started by operating the
starter. Battery voltage and water
temperature before cranking, and
average battery voltage, mass air
flow sensor output voltage and
cranking speed during cranking
are displayed.
Harness and connector
lgnition switch
START
SIGNAL
CIRCUIT Start
signal: OFF 3 ON

COOLER CYCLE
Deodorizing clean
Deodorizing Clean Filter
REMOVAL
1. Remove the instrument lower assist panel.
2. Remove the clip, and remove the cover.
3. Remove the deodorizing clean filter assembly from the blower
and cooling unit.
REPLACEMENT
Replacement period for deodorizing clean filter: Every year or
every 12,000 km
Write the necessary information on the label, and stick it in the
glove box location indicated in the left figure.

FULLY AUTOMATIC AIR CONDlTlONER
Component Parts Location
Intake door actua:or
,
Sunload sensor
Controller
B&wer temperature sensor
fan motor
@ Radiator core lower support I
Front defros!er grille (left)
1 ,?efros:er gnlie (left) t I
0 Blower fan motor relay
Engine room, right relay box I / Air conditioner relay I
Blower and cooling unit
I Blower fan motor
? Ar condlboner relay
@ Refrigerant
pressure sensor @ Compressor @ Ambtent sensor
a Liquid tank I @ Englne room. front left
I
Blower and cooling unit
lnta Instrument panel, center I
7 IJj Cluster
lid A 0 Fuse block, rear face 1

FULLY AUTOMATIC AIR CONDITIONER
Performance Test
PROCEDURE
Connect the manifold gauge to the vehicle side cooler cycle (service valve).
Attach a psychrometer to the recirculation air inlet port of the blower and cooling unit (below the glove box);
and attach a dry-bulb thermometer to the right side of the center ventilator grille.
Start and
warm up the engine.
After warming up the engine, check that the engine speed has reached the standard idle speed.
After pressing the AUTO switch, operate the fan switch, mode switch (air outlet switch),
REG switch, tem-
perature adjustment dial and switch; and satisfy the following conditions.
Fan speed: 4th
Air inlet: Recirculation
Air outlet: Ventilator (VENT)
Temperature setting:
18°C
Completely open the hood and all door windows, and close all doors.
Maintain these conditions until the cooler cycle stabilizes. (Approx.
10 minutes)
Maintain the engine speed at idle.
Measure the recirculation inlet temperature and humidity, outlet temperature, and cooler cycle high- and
low-pressures. Compare and judge the values with the "AMBIENT AIR TEMPERATURE AND PRESSURE
CHARACTERISTICS and "INTAKE AIR TEMPERATURE AND DISCHARGE AIR TEMPERATURE CHAR-
ACTERISTICS.

FULLY AUTOMATIC AIR CONDITIONER
Trouble Diagnosis
by Gauge Pressure
Connect the manifold gauge to the cooler cycle (service valve). Speculate and correct the root cause and
trouble location based on the cooler cycle pressure.
Probable cause
lnsufficient cooling
by con-
denser
Radiator fan malfunction
lmproper air guard attach-
ment
Clogged or dirty condenser
fins Corrective action
Symptom Cycle status
Repair or replace faulty parts.
Clean or repair the condenser
Pressure retums to normal
when water is splashed on the
condenser. fins.
Both high- and low-pressures
are high.
Recover all refrigerant. Re-
vacuum and charge to appro-
priate amount.
Refrigerant
over-charge
When the compressor is
stopped, the pressure drops
suddenly approx.
2 kg/cm2.
Then, the pressure drops
gradually. Recover
all refrigerant. Re-
vacuum and charge to appro-
priate amount.
Air is mixed
in the cooler cycle.
High-pressure is too high.
Temperature differences occurs
where the high-pressure pipe is
crushed or clogged. Crushed
or clogged high-pres-
sure pipe between the com-
pressor and condenser
High-pressure
is high, and
low-
pressure is too low. Repair or replace
faulty part.
Evaporator outlet is not cooled. Clogged
expansion valve
Gas leak at temperature sen-
sor
Clogging due to foreign mat-
ter
There
is a temperature differ-
ence at the liquid tank outlet
pipe, or liquid tank is covered
with frost. Remove
foreign matter in
expansion valve, or replace.
Liquid tank malfunction
(clogged strainer) Replace
liquid tank.
Both high- and low-pressures
are low. (Sometimes the low
pressure is negative.)
lmproper attachment or failure
of intake air temperature sen-
sor thermistor Replace
intake air temperature
sensor, or repair
thermistor
attachment position.
Evaporator
outlet pipe is cov-
ered with frost (no airflow).
I Inspect for refrigerant leakage.
There is some temperature dif-
ference between compressor
high- and low-pressure pipes. Recover
all refrigerant.
Re-
lnsufficient refrigerant vacuum and charge to appro-
priate amount.
Extract all refrigerant. Suff
i-
ciently vacuum and remove
moisture. Charge to appropri-
ate amount. At this time,
replace the liquid tank without
fail.
Sometimes, the evaporator out-
let is not cooled. Sometimes,
the evaporative inlet is covered
with frost. Moisture
is mixed in the cooler
cycle. (Clogging due to frozen
moisture in the expansion
valve)
Sometimes
high-pressure is
low, and low-pressure is nega-
tive.
When the compressor is
stopped, the pressures equal-
ize. There is no temperature
difference between the com-
pressor high-pressure pipe and
low-pressure pipe. Compressor
malfunction
(com-
I
pression defect)
Valve damage or failure
Faulty gasket Replace
the compressor.
High-pressure
is low, and
low-
pressure
is high.
HA-I 0