low oil pressure NISSAN GT-R 1998 Service Manual

ENGINE AND EMISSION CONTROL OVERALL SYSTEM
System Diagram (Cont'd)
Resistor a
I I~I I 1
w
C LLOE Malfunction indicator lamo
I Fuel DU~D control sional I Vehicle soeed sianal I
Parklneutral position switch signan I Refrigerant pressure sensor sianal
Air conditioner switch signal- rr -
- Power steering oil pressure switch signal
Crankshaft position sensor signal s - 0 Heated oxygen sensor output signal
Engine coolant temperature sensor signalC k - Mass air flow sensor signal r
- Ignition timing control signal ,- U I W Knock sensor output signal
Airlfuel
ratio control
signal-
Variable valve
timing
control
s~anal
Turbo pressure signal
Auxiliarv
air amount control
I
signal 2 L
g E8z E $, r
Air regulator
LT Turbo pressure sensor

ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Component Parts Location
RB20DE (UB), RB25DE
Component name I Type I Location
I Fuel iniector I Hiah-resistance I Fuel tube
I Fuel pump I Electric, turbine I Right rear of luggage compartment (in
fuel tank)
AAC valve
IAA
unit Air reaulator
5 m 3 '
Solenoid valve (Duty control)
Wax
variable intake control solenoid valve
Variable air intake control actuator
Air jet swirl solenoid valve
[RBPODE (UB)]
Air jet swirl actuator
[RB20DE (LIB)]
Crankshaft position sensor Ring gear crankshaft position sensor
[RB20DE (UB)]
Mass air flow sensor Intake
manifold collector (Upper)
Ignition coil
Canister purge control valve
Variable valve tirnina control
solenoid valve
(? o C
Solenoid valve (ON-OFF control)
Diaphragm
Solenoid valve (ON-OFF control)
Diaphragm Photoelectric (Directly driven by cam-
shaft)
Magnetic
Hot wire
w v,
Micro-mold (Built into power transistor)
Solenoid valve (Duty control)
Solenoid valve (ON-OFF control) Upper part of rocker cover
Intake manifold collector
Lower part of intake manifold
Left front
of cylinder head
Clutch housing or converter housing
Air cleaner
Throttle position sensor [Incorporates throttle valve
switch
(All models only)]
Power steering oil pressure switch
Vehicle speed sensor
ECM
(.TCM)
ECM
& IGN coil relay Cylinder head
(Top of each spark plug)
Upper part of rocker cover
Front end of cylinder head
Engine coolant temperature sensor
Heated oxygen sensor
Knock sensor Variable
resistance
ON-OFF switch
Electromagnetic power generation
104-pin digital control
Small universal relay (2M) Throttle chamber
Thermistor
Zirconia (with heater)
Piezoelectric Rear of radiator lower hose
Transmission Passenger dashboard side
Passenger dashboard side
Behind ECM
(.TCM) Water
outlet
Exhaust manifold
Cylinder block

ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Component
Parts Location (Cont'd)
" . . ., . .7
Comoonent name I TVLE a r Fuel injector High-resistance
Fuel pump
Electriclturbine
5 I unit I AAC valve I Solenoid valve (Duty control)
S Air reoulator 1 wax -1 I " - . -.
4 Ignition coil I Micro-mold (Built into power transistor)
I Canister purge control valve I Solenoid valve (Dutv control) ---- - Variable valve timing control solenold valve I Solenold valve (ONtOFF control)
Turbo pressure control solenoid valve
I Solenoid valve (OMOFF control)
Crankshaft position sensor Photoelectric
(Directly driven by cam-
shaft)
Mass air flow sensor
Hot wire
Throttle position sensor [Incorporates throttle valve
switch
(AlT model only)] Variable
resistance
Throttle motor sensor
09 Variable resistance
5 Engine coolant temperature sensor Thermistor V) Heated oxygen sensor
Zirconia (with heater)
Knock sensor Piezoelectric
Turbo pressure sensor Silicone diaphragm
Power
steering oil pressure switch
ONJOFF switch
( Vehicle speed sensor
Electromagnetic power generation
ECM
(.TCM) 104-pin digital control
Fuel pump control modulator (FPCM)
Voltage control
1 ECM L IGN co~l relay Small un~versal relay (2M) P t
.
Fuel tube
Right rear of luggage compartment (in
fuel tank)
Intake manifold collector
Cvlinder head
UOD of each soark olua)
Upper part of rocker cover
Front end of cylinder head
Next to left strut tower
Left front end of cylinder head
Air cleaner
Throttle chamber
Water outlet
Turbocharaer exhaust outlet
Cylinder
block
Upper part of rocker cover
Rear of radiator lower hose
Transmission
Passenger dashboard side
Left rear of
luaaaae comoartment
-- Passenger dashboard s~de
ECM ( TCM)

ENGINE AND EMISSION CONTROL OVERALL SYSTEM
ECM (-TCM) Terminal Layout
I GY
CH~'GN- (Data link connector for CONSULT)
Terminal NO.
1 Description Terminal 1 No I Description - - 1 I lgnition
signal (Power transistor drrve signal) Cyl. No. 1 1 '34 Iu1" positron switch signal -- ---- 2 1 Ignition signal (Power transistor drive signal) Cyl. No. 5 1 '35 1 ''2" posifion switch signal - - 3 1 Ignition signal (Power transistor drive signal) Cyl. No. 3 1 36 1 -
4 I ECM 6 IGN coil relay control signal 1 37 1 Throttle opening signal
[RB25DE.4WD,M/TS RB25DE.m RB25DEll
- - - -- - - - - 8 ( Ignition signal (Power transistor drive signal) Cyl. No. 2 ( '41 1 f-k swltch signal
5
6
7
11 ( AAC valve control signal ( 44 1 Crankshaft position sensor 120' (REF) signal
Tachometer
drive signal
-
Ignition signal (Power transistor drive signal) Cyl. No. 6
9
10
'38
39
'40
Ignition signal (Power transistor drive signal)
Cyl.
No. 4
-
12
13
"D" position switch signal
Neutral signal
(Parklneutral position switch)
"R" position switch signal
14
Symbols in ( ) next to terminal numbers indicate the data link connector terminals. Items marked with are available on RB20DE (UB) and RB25DET.m models only.
42
43
-
Fuel pump relay control signal
15
16
17
18
19
20 21
22 (CHK)
23
24 (IGN)
25
26
27
28
29
30
31
32
'33
- -
Sensor around
Air conditioner relay control signal 45
46
-
-
Malfunction indicator lamp
-
-
Ignition switch (START) signal
Air conditioner switch signal
Check (Diagnosis start)
Throttle position sensor signal
Ignition switch
(IGN) signal
Control unit ground
Power steering oil pressure switch signal
-
1 SB (select bit) 1 signal [RB25DET.A/Tl
1 Vehicle speed sensor signal (Vehicle speed sensor 2)
Headlamp switch signal
Ignition power supply
Control unit ground
Idle position switch signal Crankshaft
position sensor 120" (REF) signal
Crankshaft position sensor 1
" (POS) signal
47 Ring gear crankshaft position sensor signal [RB20DE (UB)]
Turbo pressure sensor signal
LRB25DEl-J
48
49
50
51
52
53
54
55
56
57
'58 59
'60 61
62
63
64
65
66 Power
supply for throttle position sensor, refrigerant pressure
sensor, and turbo pressure sensor
Rear defogger switch signal
Heated oxygen sensor signal
Throttle motor sensor signal [RB25DET]
SB
(select bit)
2 signal (RB25DET.ATJ
Motor throttle switch signal
[RB25DET]
Mass air flow sensor signal
Mass air flow sensor ground
Engine coolant temperature sensor signal
Refrigerant pressure sensor signal
Output shaft rotation sensor signal (Vehicle speed sensor 1)
Turbine sensor signal
[RB25DET.AlTj
Oil temperature sensor signal
Knock sensor signal
1
Knock sensor signal 2
PJT mode switch signal (POWER) [RB20DE (UB).A/Tl
DB (data bush) 1 signal [RB25DET.W
DB (data bush)
3 signal [RB25DET.W

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.