NISSAN GT-R 1998 Owner's Guide

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
CONSULT (Cont'd)
REAL TlME DIAGNOSIS IN DATA MONITOR MODE
CONSULT has two kinds of triggers and they can be selected by touching "SETTINGJy in "DATA MONITOR"
mode.
1. "AUTO TRIG" (Automatic trigger):
The malfunction will be identified on the CONSULT screen in real time.
In other words, malfunction item will be displayed at the moment the malfunction is detected by ECM. GI
DATA MONITOR can be performed continuously until a malfunction is detected. However, DATA MONI-
TOR cannot continue any longer after the malfunction detection.
2. "MANU TRIG" (Manual trigger):
Malfunction item will not be displayed automatically on CONSULT screen even though a malfunction
is detected by ECM.
DATA MONITOR can be performed continuously even though a malfunction is detected. I
AT
Use these triggers as follows: . 1. "AUTO TRIG"
While trying to detect the DTC by performing the "DTC CONFIRMATION PROCEDURE", be sure to BR
select to "DATA MONITOR (AUTO TRIG)" mode. You can confirm the malfunction at the moment it is
detected.
While narrowing down the possible causes, CONSULT should be set in "DATA MONITOR (AUTO ST
TRIG)" mode, especially in case the incident is intermittent.
When you are inspecting the circuit by gently shaking (or twisting) the suspicious connectors, compo-
Rs
nents and harness in the "DTC CONFIRMATION PROCEDURE, the moment a malfunction is found
the malfunction item will be displayed. (Refer to GI section,
"Incident
Simulation Tests" in
"HOW TO
PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT'.) HA
2. "MANU TRIG"
If the malfunction is displayed as soon as "DATA MONITOR" is selected, reset CONSULT to "MANU
TRIG".
By selecting "MANU TRIG" you can monitor and store the data. The data can be utilized for
further diagnosis, such as a comparison with the value for the normal operating condition.
I
I SELECT MONITOR ITEM 1
I MAIN SIGNALS
SELECTION FROM MENU
I I
-11 START I
I h SET RECORDING COND 1 1 k SET RECORDING CON0 1
I MANU TRIG I
I LONG TlME I
"AUTO TRIG"
A malfunction
can be
displayed on "DATA
MONITOR" screen
automatically
if detected. "MANU TRIG"
A
malfunction can not be
displayed
on "DATA
MONITOR" screen
automatically even
if
detected.

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

TROUBLE DIAGNOSES
CONSULT (Cont'd) --
CHECK ITEM (REMEDY)
FUNCTION TEST
ITEM CONDITION
JUDGEMENT
-
PWIST SIGNAL Locked position
Neutral position
Ignition
switch: ON
(Engine running)
Power steering oil pressure switch
circuit is tested when steering
wheel is rotated fully and then set
to a straight line running position. ON
OFF Harness and connector
Power steering oil pressure switch GO
CIRCUIT a Power steering oil pump
I VlAS SN CIRCUIT
0 RB20DE (UB),
RB25DE
The variable air intake system is
diagnosed by checking for opera-
tion of the actuator.
-
SWRL CONT SN
CIRCUIT
0 RB20DE (UB)
The air jet swirl control system is
diagnosed by checking for opera-
tion of the actuator.
-- -- -
a Vehicle speed sensor circuit is
tested when vehicle
is running at
a speed of 10 km/h (6 MPH) or
higher.
After warming up, idle the engine.
Ignition timing is checked by read-
ing ignition timing with a timing
light and checking whether it
agrees with specifications.
Harness and connector 877
Vehicle speed sensor
Vehicle
speed sensor input
signal is greater than 4 krnlh
(2 MPH).
VEHICLE SPEED
SEN CKT Speedometer
RS
Adjust ignition timing (by moving
camshaft position sensor or dis-
tributor)
HA
Camshaft position sensor drive
The
timing light indicates the
same value on the screen.
IGN
TIMING
ADJ
mechanism
la INJECTION SYS (Injector, fuel
pressure regulator, harness or
connector)
IGNITION SYS (Spark plug, igni-
tion coil, power transistor harness
or connector)
VACUUM SYS (Intake air leaks)
Oxygen sensor circuit
Oxygen sensor operation
Fuel pressure high or low
Mass air flow sensor
Air-fuel ratio feedback circuit
(injection system, ignition system,
vacuum system, etc.) is tested by
examining the oxygen sensor out-
put at 2,000
rpm under non-
loaded state. Oxygen sensor COUNT
More
than
5 times during 10 sec-
onds
MIXTURE
RATIO
TEST
- -- /
POWER BALANCE
Injector circuit (Injector, harness or
connector)
Ignition circuit (Spark plug, ignition
coil, power transistor harness or
connector)
Compression
Valve timing
After warming up, idle the engine.
Injector operation of each cylinder
is stopped one after another, and
resultant change in engine rotation
is examined to evaluate combus-
tion of each cylinder. (This is only
displayed for models where a
sequential
multipart fuel injection
system is used.)
D After warming up, idle the engine.
D IACV-AAC valve system is tested
by detecting change in engine
speed when IACV-AAC valve
opening is changed to
0%, 20%
and 80%. Difference
in engine speed is
greater than 25 rpm before
and after cutting off the injec-
tor of each cylinder.
Harness and connector
IACV-AAC valve
Air passage restriction between air
inlet and IACV-AAC valve
IAS (Idle adjusting screw) adjust-
ment
Difference
in engine speed is
greater than 150
rpm
between
when valve opening is at 80%
and at 20%.
IACV-AACN
SYSTEM
ECM PART NUMBER
Part number of the ECM equipped on the vehicle
can be read.
ECM: 2371 0-XXXXX
ECM-TCM: 23740-XXXXX

TROUBLE DIAGNOSES
Symptom Matrix Chart
RELATION BETWEEN CONTROL ITEMS AND SENSORSfACTUATORS
@: High possibility to control damage 0: Low possibility to control damage
Sensors and actuators
1$1$1$ r I I
Crankshaft position sensor 1@1@1@
Ring gear crankshaft position sensor
[RB20DE (UB)] @
Mass air flow sensor
I Engine coolant temperature sensor I 0 I @ I 0 i I
Heated oxygen sensor 0
Knock sensor
Vehicle speed sensor
e? - 01 0
Throttle position sensor 000 C. $ Turbo pressure sensor (TIC) 0 0
Refrigerant pressure sensor
START
lgnition switch
@ 0
IGN 000
Air conditioner switch
Parklneutral position switch
Power steering oil pressure switch
Electrical load switch
Battery
voltage
0
injector @GO I
I power transistor I I I Ignition system I I I lgnition coil I I I I
AAC valve
Fuel DumD relav
. . I I I
2 o ECM & IGN coil relay I@l@l@ 1 I I % Auxiliary electric fan relay 3 - 2 Air conditioner relay
Canister purge control valve
0
Variable valve timing control solenoid valve
Variable air intake control solenoid valve
, (NA) Air jet swirl control solenoid valve
[RB20DE (UB)] 0
Turbo pressure control solenoid valve
(TW
FPCM (TIC)
%' Dropping resistor (TIC) 2. I I 5 Air regulator
Canister 0

TROUBLE DIAGNOSES
Symptom Matrix Chart (Cont'd)
-RELATION BETWEEN TROUBLE SYMPTOMS AND SENSORS
-. - Sensors No I Hard
start start Rough
idle
Poor derivability Engine
stall
Symptom
@: High possibility 0: Low possibility
Crankshaft position
sensor (POS,
REF) Instantaneous
xeak
Ring gear crankshaft
position sensor
[RB20DE
(UB)]
s 1 Signal iigh output
,ow output
"
2 Power supply
Engine coolant tem-
perature sensor
iigh resistance
-ow resistance
- -- Heated oxygen sen-
sor
Knock sensor
iigh output
.ow output
Ipedshort
Vehicle s~eed sensor
Throttle position sen-
sor Jnstable output
'oar adjustment
Turbo pressure sen-
sor
(TIC)
Refrigerant pressure
sensor
Ignition switch (IGN)
k$n;pRnT)sw
i tch
Air conditioner switch
ParWneutral position
switch
Power steering oil
pressure switch
Electrical load switch
Multiplex communica-
tion line
Control unit power
supply
Sensor ground
Control unif and con-
nector
*: Fast idle
'oor contact
Vater intrusion

TROUBLE DIAGNOSES
Symptom Matrix Chart (Cont'd)
Sensor-related problems I Symptom characteristics and ins~ection hints
Open Engine
will not start when either REF signal circuit or POS signal circuit is open.
Neither fuel system nor ignition system outputs control signals.
Crankshaft position sensor
(POS, REF) Instanta-
neous break Symptoms
vary with the break time and the vehicle's driving conditions. Light
shock or surging will occur while the vehicle is being driven, and the engine will
stall at idle speed.
Ring gear crankshaft position
sensor
[RB20DE
(UB)]
Signal
Mass air flow sensor Open
Open
High output
Low output I Aidfuel
ratio becomes lean. Dirty hot wire or air entering the system could be the
cause. No
airfluel ratio compensation
is carried out during lean bum status. Drivability
may be affected.
Enters fail-safe mode. Driving under
2,400 rpm is allowed.
Airlfuel
ratio becomes rich. Black smoke may be noted. Poor contact at the
ground could be the cause.
Engine coolant temperature sen-
sor Open
Open
Opedshort
High resis-
tance
Low resis-
tance
Opedshort
Heated oxygen sensor
I
Airlfuel ratio becomes over-rich.
Same symptom as when signal wire is open.
Enters fail-safe mode. Malfunction indicator lamp comes ON. Ordinary driving is
allowed. Problems tend to occur when engine is cold or engine coolant tempera-
ture
is high.
Detects low engine coolant temperature. Problems tend to occur after engine
warm-up.
Detects high engine coolant temperature. Problems tend to occur when engine is
cold.
Base
aidfuel ratio is used.
lgnition timing is retarded within the knock control range. Lack of power may be
OpedShort
I noted.
Knock sensor lgnition
timing is retarded within the knock control range. Lack of power may be
High
Output
(noted.
Low output
1 lgnition timing may not be retarded when knock is detected.
Vehicle speed sensor
Throttle position sensor
Opedshort
Opedshort
Unstable out-
put
Poor adjust-
ment
Open
Turbo pressure sensor
(TE) Fuel
cut time becomes-shorter, or no fuel cut is observed.
Base idle speed is used. Fuel injection is not increased during acceleration.
AIT shift point changes for AfF vehicles.
Unnecessary cut-in fuel injection could be the cause. Poor contact at the ground
or control unit could be the cause.
ldle judgment is "OFF while idling. Condition returns
normal by turning the igni-
tion switch ON and OFF repeatedly.
Turbo pressure is judged zero. No remarkable malfunction will be detected.
Refrigerant pressure is judged high. ldle speed remains high while the air condi-
tioner is ON.
Refrigerant pressure sensor
Short Refrigerant pressure
is judged low. ldle speed remains low while the air condi-
tioner is ON.
lgnition switch (IGN)
lgnition switch (START)
Air conditioner switch Open
Engine
will not start because neither fuel system nor ignition system outputs con-
trol signals.
Engine starts in normal condition. Engine may not start when temperature is
extremefy
low.
Air conditioner will not operate. No other malfunction will be noted.
Park/neutral
position switch is judged "OFF. Target engine speed for cold engine
in
N or P position is reduced.
ParWneutral position switch is judged
"0N"I Fast Jdle is effective when the engine
is cold and the gear is in other than N and P posrtlons. Vehrcle excessrvely
creeps.
Open
Open
Parklneutral
position
switch
Short
Power steering oil pressure
switch Open
Engine may
stall when the steering wheel is turned while the vehicle is standstill
and the accelerator pedal is lightly pressed, or when the steering wheel is turned
Electrical load switch Short
Open
Open/short
Multiplex communication line
- -- during deceleration. '
Power steering switch is judged 'ON." Value will be compensated constantly.
Idle speed drops so that the engine can stall when electrical load is applied.
Torque reduction control is not performed. Therefore,
shift shock becomes
greater.
- -- -- -- -- Engine will not start because neither fuel system nor ignition system outputs con-
trol signals.
Open
Control unit power supply
- -- - - --- - - - - - O~edshort I Same symptoms as when sensor harness is open.
Sensor ground -- - Poor contact
Water intru-
sion - -- - - - - - -- -- In case of poor contact, the connector fitting may be loose. In case of water
intrusion, the engine stalls and become inoperative for a while. The engine may restart soon in some cases.
Control unit
and connector

*va r TROUBLE DIAGNOSES
Symptom Matrix Chart (Cont'd)
"- RELATION BETWEEN TROUBLE SYMPTOMS AND ACTUATORS - Actuators No
Start Hard
start Rough
idle
Poor derivability Engine
stall
Symptom
. @: High possibility 0: Low possibility
Coil Open
Open
Open
Short
I Injection port Foreign
material
Ignition signal (Power
transistor drive signal)
Ignition primary signal
(Power transistor
ground)
Primary
si'de
.- c. - k Secondary side -
2 Power supply
Fuel pump relay
Auxiliary electric fan
relay
[RB25DE,
RB25DEfl
hen
Canister purge con-
trol valve
Variable valve timing
control solenoid valve
~
Variable air intake
control solenoid valve
Air jet swirl control
solenoid valve
Turbo pressure con-
trol solenoid valve
Injector ground (Total
ground) nstantaneous
reak
I ': Fast idle

TROUBLE DIAGNOSES
Symptom Matrix Chart (Cont'd)
An open circuit causes no fuel injection to the corresponding cylinder, and the heated oxygen sensor output becomes lean. When the open circuits are
observed at all cylinders, the engine will not start.
Actuator-related malfunction
Injector Symptom
characteristics and inspection hints
Drive
circuit
lgnition signal
(POW&
transistor
drive
siqnal)
(open
Injection Open
Short
Fuel pump relay
1 Open 1 Engine will not start. In case of instantaneous break, surging may occur.
A
short circuit causes continuous fuel injection to the corresponding cylinder, and
over-rich airlfuel ratio and misfire will be noted. When the short circuits are
observed at all cylinders, the engine will not start.
Foreign
material
Clogs
L
Foreign
material causes continuous fuel injection to the corresponding cylinder.
Symptoms vary with the condition how the injection port is clogged.
Aidfuel ratio
compensation factor becomes larger.
(1 10 to 125%)
Canister purge control valve Ignition primary
signal (Power
transistor ground)
Auxiliary electric fan relay
[RB25DE, RB25DETI
1 Short
Open
Open -
Open
Open
Leaks
Open
Open
lgnition coil
AAC valve
The valve purges constantly. In summertime, engine may stall at idle speed due
i to rich aidfuel ratio. In wintertime, various malfunctions may occur due to lean
airlfuel ratio.
An open circuit causes no fuel injection to the corresponding cylinder, and the '
heated oxygen sensor output becomes lean. When the open circuits are observed at all cylinders, the engine will not start. In case of instantaneous break, symptoms vary with the break time and the
vehicle's driving conditions. Light shock or surging will occur while the vehicle
is being driven.
The engine will stall when break time is long.
AAC valve is fully closed. Symptoms vary with the base engine speed. When it is
too low, engine may stall while the vehicle is decelerating or when the power
steering load or electrical load is applied.
Power
supply
s~de
primary
Second-
arY side
Power
supply
Drive
circuit
Open Open Auxiliary
electric fan will not operate even after warm-up is completed.
The valve
will not purge. Gasoline smell may be noted when the weather is hot.
Variable valve timing control
solenoid valve
Variable air intake control sole-
noid valve (NA)
Air jet swirl control solenoid
valve
[RB20DE
(UB)]
Injector ground (Total ground) lnstanta- Symptoms vary
with the break time and the vehicle's driving conditions. Surging neous break or engine stall may occur when the instantaneous break occurred during fuel
I I injection. I
Open
, Open
Short
Turbo pressure control solenoid
valve (TIC) Valve
timing not switched.
Variable air intake valve opens, and torque in low speed range is reduced.
Variable air intake valve closes, and torque in high speed range is reduced.
Open
Short Air jet
swirl control valve remains closed.
Air jet swirl control valve remains open.
Open
Open Swing valve opens earlier, and
maximum turbo pressure is reduced.
Engine will not start
because the injectors do not operate.

TROUBLE DIAGNOSES
Symptom Matrix Chart (Cont'd)
RELATION BETWEEN TROUBLE SYMPTOMS AND ENGINE MECHANICAUACCESSORIES
Malfunction of the gasoline engine will not occur when the three elements of combustion (compression
pressure, aidfuel mixture, and spark) are all normal. Though the
aidfuel mixture and the spark (ignition tim-
ing) are controlled by ECM
(.TCM) control unit, if the engine mechanical is malfunctioning,
a malfunction will
occur. (The table below shows universal cases. Some cases may not apply to the vehicle.)
Engine mechanical-related malfunction
0: High possibility 0: Medium possibility A: Low posstbility
I No I Hard
start start
I Air sucked in at oil level gauge
Air sucked in at oil filler cap
Loose air duct
(A-F/M downstream) 0 A
Misconnection of canister piping
0 A
Cracked intake manifold
0 A
Aidfuel
mix-
ture
PCV valve stuck open
Clogged fuel strainer
0 A
Clogged air cleaner element
Malfunctioning pressure regulator
A 0 0 0
Improper gasoline properties A000
EGR valve stuck open 0 0
Deposits on valve 0 0
Excessive canister purge volume
Misconnection of high-tension wire
Improperly adjusted ignition timing
Malfunctioning spark plug
High-tension wire leaks
A000
Spark Distributor cap leaks
A000
Compres-
Improper valve contact
sion pres-
. a080
sure Worn piston ring ~080
Others
Clogged catalytic converter or
exhaust system A00
Low base idle speed A
A
Foreign material (vinyl, etc.) in fuel 1 tank
Clogged radiator or capacitor
IIII
Rough idle I Poor drivability Engine stall
- - - - - - -- ': Fast
idle
Adding to the items listed above, check the following.
Wiring harness for tension Ground wires for loosenes nuids and oils for levels All connectors for connection Battery connections for loosenes and corrosion Drive belts for loosenes