service NISSAN GT-R 1998 Service Manual

SERVICEMANUAL

NISSAN
MODEL R34 SERIES
FOREWORD
This Sewice Manual contains infor-
mation concerning necessary ser-
vice procedures and relevant data
for the model
R34 series.
All information, illustrations and
specifications contained in this Ser-
vice Manual are based on the latest
product information available at the
time of publication. If your NISSAN
model differs from the specifications
contained in this
Sewice Manual,
consult your NISSAN distributor for
information.
The right is resewed to make
changes in specifications and meth-
ods at any time without notice.
QUICK REFERENCE INDEX I
0 1998 KISSAN MOTOR CO., LTD. Printed in Japan
A11 rights reserved. No part of this Service Manual may be reproduced or stored in a retrieval system, or transmitted in any form, or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of Nissan Motor Company Ltd.. Tokyo, Japan.

HOW TO USE THIS MANUAL
b This Service Manual only contains the service data specifications and trouble diagnosis informa-
tion such as self-diagnosis,
CONSULT, circuit diagram and so on.
b For other information not specified in this manual, refer to Japanese version Service Manual (Pub.
No. A006029) and wiring diagram manual (Pub. No.
WD8EOR34JO).
IMPORTANT SAFETY NOTICE
The proper performance of service is essential for both the safety of the technician and the efficient
functioning of the vehicle.
The service methods in this Service Manual are described in such a manner that the service may be
performed safely and accurately.
Service varies with the procedures used, the skills of the technician and the tools and parts available.
Accordingly, anyone using service procedures,
took or parts which are not specifically recommended
by
NISSAN must first be completely satisfied that neither personal safety nor the vehicle's safety will
be jeopardized by the service method selected.

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
NISSAN
CONSULT
START
I 1
I SUB MODE BR455C
1 b SELECTeYSTEM
[ ENGINE
I
b SELECTDIAG MODE n]
WORK SUPPORT
SELF-DIAG
RESULTS
DATA MONITOR
ACTIVE TEST
FUNCTION TEST
, ECM PART NUMBER
SEF288S
CONSULT
CONSULT INSPECTION PROCEDURE
Turn ignition switch OFF.
Connect "CONSULT to data link connector for CONSULT.
(Data link connector for CONSULT is located under the instru-
ment lower cover on the driver's side on both LHD and
RHD
models.)
I
Turn ignition switch ON.
Touch "START'.
Touch "ENGINE".
Perform each diagnostic test mode according to each service
procedure.
For further information, see the CONSULT Operation Manual.

TROUBLE DIAGNOSES
P ECM (aTCM) InputDutput Signal Reference
Value
SIGNAL VOLTAGES MEASURED WITH OSCILLOSCOPE AND CIRCUIT TESTER
- Signal voltages measured at ECM (-TCM) terminals (terminals for engine control) with a circuit tester and
example of waveforms displayed on an oscilloscope are shown below.
For signal terminals for A/T control, refer to "AIT Trouble Diagnosis" in AT section.
Measured data are affected by many factors such as irregularity of parts, vehicle history, operating
conditions, environment, service status, and measuring instruments and methods.
Terminal
No.
RX / TX
Signal name
I nition signal 8 ower transistor
drive signal)
CH~~"N
ECM & IGN coil
relay control signal (Data
link connector for CONSULT)
Tachometer drive
signal
NOTE: Above
At idle
When cranking: Approx. 0.1 2V
At idle: Approx. 0.1 V
?pprox. 1V
,During approx. 1.5
sec. after ignition switch turned OFF: 4pprox. 1 V 1.5 sec. after ignition switch turned OFF: Battery voltage)
:RB20DE
(UB),
RB25DEJ
Approx.
1.2V
:RB25DET]
Approx.
7.2V At
approx. 2,000 rpm
Approx. 0.15
- 0.25V
Approx. 3V
voltages are measured values obtained by analog circuit tester.
EC-39

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
DESCRIPTION
CONSULT indicates operation timing of each solenoid such as electrical shift timing and lock-up timing.
Therefore, when there is a definite difference between shift timing detected from shift shock (or engine
speed variation) and the one indicated by CONSULT, mechanical parts other than solenoids and sensors
(including hydraulic circuit) may be malfunctioning. In this case, check the mechanical parts using appli-
cable diagnostic procedures.
Shift schedule (which implies gear position) displayed on CONSULT and that indicated in Service Manual
may differ slightly. This occurs because of the following reasons:
Actual shift schedule has more or less tolerance or allowance.
Shift schedule indicated in Service Manual refers to the point where shifts start, and gear position dis-
played on CONSULT indicates the point where shifts are completed.
Shift solenoid valve A or B (ON/OFF) is displayed on CONSULT at the start of shifting. Gear position
is displayed upon completion of shifting (which is computed by TCM).
To make sure the part No. of ECM-TCM on CONSULT, touch "ENGINE" to verify "C/U PART NUMBER".
SELF-DIAGNOSIS PROCEDURE
Refer to "CONSULT Instruction Manual - Supplement" in details.
1. Turn ignition switch OFF.
2. Connect CONSULT connector to data link connector.
3. Start engine.
4. Touch "START', "NT and "SELF-DIAG RESULTS" sequen-
tially on CONSULT screen.
5. Self-diagnosis results are displayed on the screen.

TROUBLE DIAGNOSES
CONSULT (Cont'd)
SELF-DIAGNOSTIC RESULTS MODE
Diagnostic item 1 Diagnostic item is detected when ... Inspection item - -- -
I TCM does not receive vehicle speed sensor 1 signal due to
open circuit, etc.
TCM receives improper signal during driving. After ignition switch is turned ON, vehicle speed sensor 2 receives improper signal until vehicle starts to run.
VHCL
SPEED
SEN.A/T Vehicle
speed sensor 1 circuit
TCM does not receive vehicle speed sensor 2 signal due to
open circuit, etc.
TCM receives improper signal during driving.
VHCL
SPEED
SEN.MTR Vehicle
speed sensor 2 circuit
TCM detects
folfowing conditions during driving (Except N and
P positions). 0 Excessively high throttle position sensor signal voltage Excessive1 low throttle position sensor signal voltage with idle
switch OF; or full switch ON
THROTTLE
POSl
SEN
Throttle position sensor circuit
SHIFT SOLENOIDN A
SHIFT SOLENOIDN B Shift
solenoid A circuit
Shift solenoid
B circuit
Overrun clutch solenoid circuit
TIC
CLUTCH SOW
I
OVERRUN CLUTCH SN
Lock-up solenoid circuit Specified voltage is not applied to solenoid due to open and/or
short circuit.
LINE
PRESSURE SN
I Line pressure solenoid circuit
0 Excessively low supply voltage to TCM during driving
Excessively high si nal voltage of AIT fluid temperature sensor
(excessively low d fluid temperature) during driving This message is displayed only when malfunction occurs with ignition switch ON, and does not have memory func-
tion.
fluid temperature sensor circuit,
TCM power supply circuit, or
throttle position sensor power sup-
ply circuit
BATT/FLUID
TEMP SEN
ENGINE SPEED SIG
I Excessively low engine speed during driving Engine speed
signal circuit
Turbine sensor circuit
TURBINE
SENSOR
(Except
RB20DE)
SHIFT SOLENOIDN C
(Except
RB20DE)
TCM does not receive input shaft speed sensor signal due to
open circuit,
etc.
0 TCM receives improper signal during driving.
0 TCM does not receive shift solenoid A pressure detection switch
signal due to open
andfor short circuit. Shift solenoid A pressure
detection
switch circuit
MANUAL MODE SW
(Except
RB20DE)
TCM does not receive proper manual mode switch signal due to
open and/or short circuit. Manual
mode switch circuit
ENGINE BRAKE
C/U'1
(Except
RB20DE)
Shift control unit does not operate properly due to open and/or
short circuit of each
input/output signal wire.
Malfunction occurs in shift control unit. Each
signal wire circuit connected
to shift control unit
'INITIAL START*
Power supply to TCM is shut down, and self-diagnostic memory
function is canceled due to battery removal, etc.
CONTROL UNIT (RAM)
I Malfunction is detected in TCM memory (RAM) function.
CONTROL
UNIT
(ROM)
I Malfunction is detected in TCM memory (ROM) function.
'1 : Indicates shift control unit.
DATA MONITOR PROCEDURE
Refer to "CONSULT Instruction Manual - Supplement" and "CON-
SULT Service Manual
- Supplement" in details.
1. Turn ignition switch OFF.
2. Connect CONSULT connector to data link connector.
3. Turn ignition switch ON.
4. Touch "START', ''AT and "DATA MONITOR" sequentially on
CONSULT screen.

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.