1998 NISSAN GT-R ESP

ENGINE AND EMISSION CONTROL OVERALL SYSTEM
A 1 System Description
The engine control system, which performs various controls such
as the fuel injection control and ignition timing control with a single
control unit, has been adopted.
Diagnostic system applicable to
CONSULT has been adopted for
easier inspection, service, and trouble diagnostic operations.
Description of Engine Control
I
Description \,
Performs optimum fuel injection for every operation condition for
improved exhaust performance and response.
Adopts
SOFlS (Sophisticated and Optimized Fuel Injection System)
control for optimized fuel injection.
Adopts
airbuel ratio feedback
learning control that performs
com-
0
pensation of airfiuel ratio for improved drivability when the system is
in a transitional condiiion due to sudden change in
airfiuel ratro.
Uses an ignition timing map stored in the control unit to perform
controls so that the optimum ignition timing is obtained for every
operating condition.
Performs knock control, in which the ignition timing is advancedl
retarded according to the presence of knocking, so that the
opti- 0
mum i nition timing is obtained for every operating condition and
type
oPfue1.
Performs feedback control to obtain the target idle speed for various
conditions, such as during warm-up or when the air conditioner is
actuated, via the
AAC valve that adjusts the intake air amount when
O
the throttle valve is fully closed.
Turns the fuel pump relay OWOFF according to the engine speed
Fuel
injection control
Ignition timing control
Idle
speed
control
Fuel pump drive signal. In RB25DET model, FPCM (Fuel Pump Control Modulatoi) control O
has been adopted for reduced idle noise.
Heated oxygen sensor
heater control
Air conditioner cut control
Promotes warm-up of the heated oxygen sensor for improved air1
fuel ratio feedback function. 0
Tums the air conditioner relay OFF at starting or during acceleration to reduce the engine load. 0 -- Auxiliary electric fan con-
trol
Engine,
M, TCS,ABS integrated control
Tums the auxiliary electric fan relay ONIOFF according to the - engine coolant temperature signal and air conditioner signal.
Reduces engine toque during gearshift or when TCS (Traction
Control System) is being operated via a multiplex communication
lino 0
- -
Variable valve timing con-
trol According to the engine speed and load, controls the cam phase by
hydraulic pressure to change intake valve
open/close timing for
Increased engine torque at low and middle speeds and for
enhanced
out~ut.
I o I
Canister purge control air
intake valve control
Air
jet swirl control Performs duty
control of the canister purge air according to various ooeratina conditions.
0 -r-~ e-- ---
-
Controls the intake air passage in the intake manifold collector to
increase engine torque at low and middle speeds and to enhance
output. 0
According to operation conditions, turns the air jet swirl control sole-
noid valve ONIOFF to openlclose the air jet swirl control valve
for 0
pressure control
stable combustion.
Tums the Turbo pressure control solenoid valve ONIOFF according - to operation conditions.
Ensures the vehicle's safe operation and enables the vehicle
to be
Fail-safe and backup con-
trols
Diagnostic system driven
in an emergency when any of the system major components
(microcomputer in the control unit, engine coolant temperature
0
sensor, etc.) fails.
For easier trouble diagnosis, self-diagnostic system is adopted and
the existing diagnostic system is modified so that CONSULT can be
0 used.

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
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)
Engine mechanical-related malfunction I Symptom characteristics and inspection hints
Airffuel
ratio becomes lean.
Air sucked in at oil filler cap
Aidfuel ratio compensation factor becomes higher.
a Intake manifold induction vacuum becomes lower.
I Cracked intake manifold I
Misconnection of canister piping Use an induction vacuum (pressure) gauge for check.
' Common to all air sucking conditions from air intake system.
-
PCV valve stuck open
I Malfunctioning pressure regulator I Various symptoms occur depending on the fuel pressure.
Abnormal noise (peep) may
be heard.
Air/fuel
mixture
Improper gasoline properties Various
symptoms occur depending on the properties.
IEGRiale
stuck open
I
Clogged fuel strainer .
Clogged air cleaner element
Deposits on valve
r
Symptoms vary with the condition how they are clogged. However, the
symptoms tend to occur when the vehicle is driving at high speed and
under high load.
I
Air/fuel ratio becomes lean. Airfluel ratio compensation factor becomes
higher.
Excessive canister purge volume
I
Engine may stall when the accelerator pedal is lightly pressed. (Especially
in summertime.)
Misconnection of high-tension wire Check if the ignition timing
is correct. 1 Improperly adjusted ignition timing 1
Malfunctioning spark plug 1
Corn- I Improper valve contact I Symptoms vary with the degree of contact and the number of cylinders. '
High-tension wire leaks
Distributor
cap leaks Symptoms
vary with the degree of leaks.
Clogged catalytic converter or exhaust sys-
l tem , In many cases, engine stalls and then restarts after a while. I
pression I
Low base idle speed
pressure
Worn piston ring I
Engine may
stall while the vehicle is decelerating or when the power '
steering load or electrical load is applied.
Symptoms vary
with the degree of wear and the number of cylinders.
I
Air conditioner load too heavy I Too much refrigerant in the system. j
Others Dragging
brake
Belt tension too high
1
I Clogged radiator or capacitor I
ArJ load too heavy
Foreign material (vinyl, etc.) in fuel tank Insufficient A/T fluid (FR model)
Symptom tends to occur when fuel level in the tank becomes lower.

TROUBLE DIAGNOSES
Control Unit Input/Output Signal Specifications
Refer to EC section ("ECM.TCM or ECM Input/Output Signal
Reference Value").
USING CONSULT -
Monitor item Indication value Operating status
Throttle position sensor Approx.
0.4 - 4.OV
Throttle fully - closed to fully-open --
AK fluid temperature sensor I Appro~. 1.5 - 0.5V I A/T fluid: Appro~. 20 - 80°C -- - - --- -
ON Overdrive control switch: OFF
Lever switch
OFF Overdrive control switch: ON
Line pressure
duty 29 - 94% Low
pressure - High pressure
Lock-up duty
4 - 94% Lock-up released - Lock-up engaged
USING CIRCUIT TESTER
Terminal
No.' 1 Condition Specifications
.- Refer to EC section
("ECM-TCM or
5 (39) Engine speed signal - ECM Input/Output Signal Reference
Value*).
Voltage increases gradually in
Throttle position sensor
signal After
engine warm-up, depress accelerator pedal
slowly. response
to throttle position.
Fully-closed throttle
: Approx. 0.5V
Fully-open throttle : Approx. 4.2V
24 (I0) Power source
31 (19) Turn
ignition switch ON. Battery
voltage
Turn ignition switch OFF. Approx.
OV
--
25 (25) 1 Ground 32 (48) Turn ignition switch ON. Approx. OV
Shift control
signal SB1 - - 28 (I4) (Except RB20DE)
Vehicle speed sensor
2 When vehicle is moved at 2 to 3 km/h for more than Voltage varies approx. between OV 29 (40) (vehicle speed
signal in 1 m. and 4.5V intermittently.
speedometer)
*: Each number in parenthesis ( ) shows the terminal No. for TCM (RB25DE).

TROUBLE DIAGNOSES
n t
\-Test port for "D", "2", and "1" positions
I 'Test port for "I?" position I
Line pressure specification
Basic Inspection
Arr FLUlD
Check A/T fluid for leakage and fluid level.
Check A/T fluid status.
SHIFT CONTROL
Check and adjust A/T position.
Line Pressure Test
1. Check engine oil level. If necessary, add oil.
2. Drive vehicle for approximately 10 minutes until A/T fluid
reaches normal operating temperature between
50 and 80°C,
and check A/T fluid level. If necessary, add fluid.
When
ambient temperature is 20°C, A/T fluid operating tem-
perature
usually becomes between 50 and 80°C for approxi-
mately
10 minutes' drive in urban traffic.
3. After warming up IW', remove fluid pressure detection plug,
and install pressure gauge (Special Service Tool:
ST2505
S001) to corresponding line pressure port.
CAUTION:
0 To remove or install the fluid pressure detection plug, use
standard socket wrench (width across flat:
12 mm).
Detection plug should not be reused because thread-lock
compound is applied
to the plug.
4. Set parking brake and block wheels.
5. Start engine and measure line pressure at idle and stall speed.
CAUTION:
When measuring line pressure, depress brake pedal fully.
When measuring line pressure at stall speed, refer to
"Stall Test" (AT-17).
I p- Line pressure MPa (kg/crn2)
Engine speed
I "RW position "On, 'Z", "1" positions (4AT)
"Dm,
"3", "2" positions (M-AT)
At idle speed
At stall speed 0.58 - 0.62 (5.9 - 6.3) 0.47 - 0.51 (4.8 - 5.2)
1.71
- 1.78 (1 7.4 - 18.2) 1.22 - 1.29 (1 2.4 - 13.2)

TROUBLE DIAGNOSES
Line Pressure Test (Cont'd)
JUDGEMENT OF LINE PRESSURE TEST
At idle
speed
At stall
speed Judgement
Line pressure is low in all
positions.
Line pressure is low in par-
ticular position.
Line pressure is
high.
Line pressure increase is
poorer than that measured at
idle speed.
Line pressure increases but
does not reach specification.
Line pressure is low in par-
ticular position. Possible
causes
Pressure supply system malfunction or low oil pump output
Examples:
0 Oil pump wear
Control piston damage
Pressure regulator valve or plug sticking, and weak spring
Fluid pressure leakage between oil strainer and pressure regulator valve through oil Eg
Pump
Low idle speed
After line pressure is supplied from manual valve, fluid pressure may leak between devices
or circuits of corresponding position.
1
Malfunctions of sensors or pressure regulation function. El
Examples:
Misadjustment of throttle position sensor
PJT fluid temperature sensor damaged ST
Poor operation of line pressure solenoid (stuck with OFF status, clogged filter, or open
harness)
Pressure modifier valve sticking F%
Pressure regulator valve or plug sticking
Malfunctions of sensors or pressure regulation function
Examples:
EILA
Misadjustment of throttle position sensor
TCM, ECM.TCM damaged la
Poor operation of line pressure solenoid (stuck or shorted with ON status)
Pressure regulator valve and plug sticking
Pressure modifier valve sticking
sf$
Pilot valve sticking and pilot filter clogged
Malfunctions of pressure supply system, sensors, or pressure regulation function
Examples:
Misadjustment of throttle position sensor
Control piston damage
Poor operation of line pressure solenoid, and filter sticking or clogged
Pressure regulator valve and plug sticking
Pressure modifier valve sticking
Pilot valve sticking and pilot filter clogged
After line pressure is supplied from manual valve, fluid pressure
may leak between devices
or circuits of corresponding position.
Stall Test
1. Check engine oil level. If necessary, add oil.
2. Drive vehicle for approximately 10 minutes until A/T fluid
reaches normal operating temperature between
50 and 80°C,
and check A/T fluid level. If necessary, add AfT fluid.
When ambient temperature is
20°C,
A/T fluid operating tem-
perature usually becomes between 50 and
80°C for approxi-
mately
10 minutes' drive in urban traffic.
3. Set parking brake and block wheels.
4. Statt engine, depress brake pedal, and move selector lever to
"D" position.

TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
\ I1 // \ 11 // =-I= or =mj= // 11 \ // 11 \
1, = 2.5 sec. t, = 2.0 sec. t, = 1.0 sec.
RB20DE 10 judgement flashes.
Stan signal Malfunctioning unit and circuit I
Except RBPODE 13 judgement flashes.
signal Malfunctioning unit and circuit I
POWER INDICATOR LAMP OR DUAL MATIC A/T
WARNING LAMP INDICATION
If malfunction occurs in electrical system, indicator lamp stays on
longer at corresponding circuit.
Flashing
order
t5 1 Overrun clutch solenoid
1
2
3
4
5
7 1 Lock-up solenoid
Malfunctioning
unit and circuit
Vehicle speed sensor
1
Vehicle speed sensor 2
Throttle position sensor
Shift solenoid
A
Shift solenoid B
I
W fluid temperature sensor, TCM power supply, or throttle posi-
tion sensor power supply
RB20DE
9 1 Engine speed
signal Except
RB20DE
10 1 Line
pressure solenoid I Turbine sensor
I - I Line pressure solenoid
12 1 - I Total control signal
When indicator lamp repeats flashing in 4 Hz, the following malfunctions
may exist: (Insufficient memory backup
powerflCM repiacement1Battery
has been disconnected for prolonged
periodllow battery power)
13
No flashes
HOW TO ERASE SELF-DIAGNOSTIC RESULTS
To facilitate cause investigation of malfunction that is less likely to
reappear, the TCM always stores self-diagnostic results during cus-
tomer operation. This memory cannot be erased even if ignition
switch
is turned ON and OFF repeatedly. To erase the seif-diag-
nostic
results, turn ignition switch
OFF after self-diagnosis has
been performed, or use
"ERASE" function of CONSULT.
- - - - Shift control unit
PNP switch, idle
switch/full switch
Overdrive control switch Stop lamp switch