1998 NISSAN GT-R Service Manual

TROUBLE DIAGNOSES
ECM (-TCM) Input/Output Signal Reference
Terminal No. Signal name
At approx. 2,000 rprn At idle
When cranking: Approx.
1.3V
Approx.
1.4V
ECLl426D
Crankshaft position
sensor 120" (REF) sig-
nal At idle: Approx. 1.35 - 1.4V
When cranking: Approx.
2.6V
Approx.
2.6V
Crankshaft position sensor 1" (POS) signal jle: Approx. 2.6V
ECLl428C
When cranking (DC range): Approx. (AC range): Approx.
DC range: Approx.
0.1V
AC range: Approx. 3.2V
Ring gear crankshaft
position sensor signal
[RB20DE
(UB)]
At idle DC range - Approx. 0.1 V [Ac range]. /\ppmx. 1 .W (v: 15 10 5 0
t (When engine raced sirddenly: Approx. 2.7 - 3.1V)
Turbo
Dressure
sensor
signal ' [RB25DET]
Throttle position sensor,
refrigerant pressure
sensor, turbo pressure
sensor power supply
Rear defogger switch
signal
-
49
NOTE: ,
2ear defogger switch OFF: Approx. OV
Rear defogger switch ON: Battery voltage
C-
bove voltages are measured values obtained by analog circuit tester.
EC-42

TROUBLE DIAGNOS
ECM (.TCM) lnpu
:s
3utput Signal Reference
Value (Cont'd)
.. No.
Fluctuates between approx. 0.1 to
0.4V and approx.
0.7 to
0.9V At
idle
- I I - I I -
I
I
- are measured
At approx. 2,000 rpm
:v: i .5 I .O 0.5 0
ECL 1 8645 11jllllllll ECL 1 8630
Throttle motor sensor
signal
[RB25DET'J Approx. 3.4V
I (Voltage becomes lower when TCS operates.)
Motor throttle switch
signal
[RB25DET]
Approx.
4.7V
Mass air flow sensor
signal
t
(When TCS is operating: Approx. OV)
Ignition switch ON: Approx.
0.2V
At idle: Approx.
1
.I - 1.2V Approx.
1.6 - 1.7V
Mass air flow sensor
ground Approx.
OV
I
Coolant temperature approx. 20°C: Approx. 3.5V
Coolant temperature approx.
80°C: Approx. 1.2V
Approx. 0.36V min.
(Voltage increases as the air conditioner refrigerant
pressure increases.)
Approx. 0.4
- 2V (') ': Voltage varies with measuring range (internal resis-
tame) of a circuit tester.
Battery voltage
C
+
+
+
56
-
62 1 Knock sensor signal 1
Engine coolant tem-
perature sensor signal
57
- -- -
63 1 Knock sensor signal 2
Refrigerant pressure
sensor
67 Control unit power
sup-
72
I PIY Receive (Data input to
control unit) 1
Transmit (Data output
from control unit) CONSULT
connected: Approx. 0.25V
CONSULT
not connected: Battery voltage
CONSULT connected: Approx.
9V max. CONSULT not connected: Approx. OV
C
Fan stopped: Battery voltage
Fan operating: Approx. 0.2 - 0.3V 78
NOTE: Above
Auxiliary electric fan
relay control signal
[RB25DE, RB25Dm
voltages values obtained
analog circuit
tester.

TROUBLE DIAGNOSES
ECM (-TCM) Input/Output Signal Reference
Terminal No.
108
- NOTE:
Signal name
CM.TCM, TCS/ABS
tegrated control signal
dultiplex communica-
&DE.m,
B25DETj
attery power supply
ijector drive signal
3attery voltage When cranking: Approx.
10.5V
Value (Cont'd)
(v) 50 40 30 20 10
0
At idle: &Wry voltage
A:
idle
Approx. 2V
rariable
air intake con-
:ol solenoid valve con- switch ON: Battery voltage (Solenoid valve
rot signal
RB20DE (UB), At idle: Approx. 0.2
- 0.3V (Solenoid valve ON) At
approx. 2,000
rpm
t
3B25DEI ' .
-urbo pressure control iO1enOid valve Battery voltage (Solenoid valve OFF)
iianal
4ir jet swirl sole- Coolant temperature below approx. 70°C: Approx.
0.9V (Solenoid valve ON)
'Oid Coolant temperature approx. 70°C and above: Battery
RB20DE (VB)] voltage (Solenold valve OFF)
[RB20DE (UB), RB25DEl
Air conditioner OFF: Battery voltage
Air conditioner ON: Battery voltage Approx.
10V
(After approx.
15 sec.)
Zanister
purge control
~alve
control signal
M 30 20 10 0
(Waveform indicates when air conditioner is
ON.)
[RB20DETJ
Air conditioner OFF: Battery voltage
Air conditioner ON: Battery voltage
4 Approx. 1OV
(After approx. 15 sec.) Slightly lower than battery voltage
t At
approx. 3,650 rpm and above [RB2ODE (UB)]
At approx. 3,500 rpm and above [RB25Dq : Battery voltage (Solenotd valve OFF)
t [When engine raced suddenly: Approx. 0.3V (Solenoid
valve ON)]
t Coolant temperature approx. 70°C and above, and
driving at approx. 3,300 rpm and above [MTT] Coolant temperature approx. 70°C and above, and
driving at approx. 3,000 rpm and above [A/T1 : Approx. 0.9V (Solenoid valve ON)
Approx.
9V
Approx. 9V
I (Waveform indicates when air conditioner is ON.)
tester.

TROUBLE DIAGNOSES
ECM (.TCM) InputlOutput Signal Reference
Value (Cont'd)
I Signal name
No. At
idle 7 At approx. 2,000 rpm
Control unit power sup-
ply (Counter-electromo-
live current feedback
circuit)
Fuel pump terminal
voltage control output
1 signal
IRB25DETI
Variable valve timing ,- control signal Battery voltage
Ignition switch at START: Approx.
OV During approx. 30 sec. after engine started with cool-
ant temperature 50°C or above: Approx. OV At idle: Approx. 1 OV
Battery voltage (Solenoid valve OFF)
Approx.
0.3V
Approx. OV
I t [With driving wheels lifted and gear in D position:
Approx. 0.45V (Solenoid valve ON)] AT
Approx. 0.3V (At approx. 2,800 rpm and above: Battery voltage) 1 I I
NOTE: Above voltages are measured values obtained by analogue circuit tester. BR

AUTOMATIC TRANSMISSION
SECTION
AT
CONTENTS
SHIFT LOCK SYSTEM .................................................... 2
Component Parts Location .......................................... 2
Shift Lock Circuit Diagram ........................................... 2
Reverse Buzzer Circuit Diagram ................................. 2
TROUBLE DIAGNOSES ................................................. 3
System Description .................................................... ..3
Fail-safe Function ...................................................... ..3
................... Shift Mechanism ............. .........,,.............. .5
Clutch and Band Chart ................................................ 6
Component Parts Location .......................................... 7
........................................................... Circuit Diagram .8
Control Unit Input/Output Signal Specifications ....... .I0
Shift Pattern .............................................................. 1 3
............................................................ Shift Schedule 15
....................................................... Basic Inspection. -16
Line Pressure Test ..................................................... 16
................................................................... Stall Test 17
.................................................................. CONSULT 9
.......................................................... Self-diagnosis ..23
Symptom Chart. ........................................................ -25

SHIFT LOCK SYSTEM
Component Parts Location
Control device pJ/ I '-#I
Park position

Key interlock cable
Shift Lock Circuit Diagram
I AfT device connector
Brake SW connector
4AT M-AT
Terminal No. in parenthesis is used for M-AT. AfT device AT01 O57C
6 (2)
$5 - 5
IOA / 2j nI1 - (6)
Brake SW
Reverse Buzzer Circuit Diagram
Shift lock solenoid
Park position SW ~-
Connectors
1 1 )29m [ I]l~a!!b-ll1ll1 36 , &- 551 l\li I i I1 I I I I! I TK 20 pins (Wh~te)
TK 24 pins (Brown) TK 20 pins (Brown) AT01 056D
# 12
b
-
#ll PNP SW 36 Reverse lamp 29
# 28 9
1 1 Meter C/U 155 4 (with
integrated buzzer) ,

TROUBLE DIAGNOSES
System Description
Vehicle with RB20DE and RB25DET engine has TCM integrated into ECM. Vehicle with RB25DE engine has
TCM and ECM separately.
Fail-safe Function @ When malfunction occurs in each sensor and solenoid, the fail-safe functions below enable vehicle to be
driven.
VEHICLE SPEED SENSOR 1 (Output shaft speed sensor)
Inputs a signal from vehicle speed sensor in speedometer. EG
THROTTLE POSITION SENSOR
Detects throttle opening by idle switch and full switch, and controls line pressure as follows. I 1 I Idle switch
-
--
I
--
ON OFF I Minimum oil pressure I 0/8 ST
I
OFF OFF
Full switch
ON Maximum oil pressure
PNP SWITCH
When the multiple PNP switch signals are input to TCM and ECM-TCM, the priority of selector lever position I28
becomes as follows by internal TCM determination.
4AT D, N, R, 2, 1 I%$ M-AT D, N, R, 3, 2
Because the hydraulic circuit of the control valve is switched by manual valve according to the selector lever
position, however, actual operating condition of vehicle becomes as follows.
EL
I N I "N" and other position signals I N
Line pressure
218
P
R
- - -- pp - pp - -
4AT I D I "D" and other position signals I Dl*DP*Dd
Throttle opening I
418 BR
Running status
Actual lever position
1 "2 and other position signals I 21 ~22
PNP switch input signal
"P and other position signals
"R" and other position signals
--
r"2 and "1" 21 ~22
P 83
R
I 2 1 "2" and other position signals / 21 42
M -AT
3
L
1
P
R
N
D
"1" and other position signals
"P" and other position signals
"R" and other position signals
"N" and other position signals
"D" and other position signals
I
l,++l2
P
R
N
D1t;.D2c*D3
"3 and other position signals
"3" and "2" position signals
3, -3,-3-3,
3, +3, +3,

TROUBLE DIAGNOSES
Fail-safe Function (Cont'd)
SHIFT SOLENOID A, B
When a malfunctioning signal of solenoid is input to TCM and ECM-TCM, the gear is shifted as follows.
Normal Abnormal solenoid A Abnormal solenoid B Abnormal solenoid A/B Shift positions A B Gears A B Gears A I3 Gears A 8 Gears
0 0 1 st o-+x 03x - - - -
-- 0: Solenoid ON X: Solenoid OFF -: Abnormal
LINE PRESSURE SOLENOID
When a malfunctioning signal of solenoid is input to TCM and ECM-TCM, the line pressure solenoid is turned
OFF, and the line pressure is set to maximum oil pressure.
LOCK-UP SOLENOID
When a malfunctioning signal of solenoid is input to TCM and ECM.TCM, the lock-up solenoid is turned OFF,
and the lock-up
is released.
OVERRUN CLUTCH SOLENOID
When a malfunctioning signal of solenoid is input to TCM and ECM-TCM, the overrun clutch solenoid is turned
OFF, and the overrun clutch is engaged to apply the engine brake during deceleration.
MANUAL MODE SWITCH (M-AT)
When a malfunctioning signal of manual mode switch is input to TCM and ECM.TCM, the gear is controlled
with normal "D" position.
SHIFT CONTROL UNIT (Except RB20DE)
When a malfunction occurs in the shift control unit, the shift solenoid NB are turned OFF, and the gear posi-
tion
is controlled with 3rd speed.
TURBINE SENSOR (Except RB20DE)
Controlled by vehicle speed sensor 1 in the same way without turbine sensor