NISSAN GT-R 1998 Workshop Manual

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

TROUBLE DIAGNOSES
Shift Mechanism
1 Turbine sensor 1
tine pressure solenoid I 1
Shift solenoid B
Full switch
ECM-TCM
(All side) (RB20DE, RB25DET) or TCM (RB25DE) p-
ECM.TCM (Engine side) * I
(RB20DE. RB25DET) or Venrle speed sensor 2
ECM (RB25DE) ,
1 (RB25DET)
POWER ~nd~calor lamp @AT;
( POWER (Except M-AT) ] 1 SNOW I
Shift control unit
(Except RB20DE)
Overdrive control switch
I
O/D OFF
indicator lamp
Steering shift main switch
- ATN 1983D

TROUBLE DIAGNOSES
Clutch and Band Chart
U0.C
(Low one-
way
clutchl L&R/B
(Low and
reverse
brake)
F/O C
(Forward
clutch)
.
Remarks
PARK POSI-
TION
REVERSE POSITION
O/C
(Overrun
clutch)
*I@
'I@
'18
@
NEUTRAL
POSITION
*"
c'utch)
0
0
WC
clutch)
(Reverse
0
P
R
N
Automatic shift
0
0
FIC
(For-
ward
clutch)
0
0
0
69
0
Band servo
'4
2 Automatic shift
1 st
2nd
-3rd 4th
1 st
1. Locked in 1st
-
4th apply
0
2nd apply
0
'263
*3@
2nd
I st
2nd
0
0
0
DUAL MATIC M-ATx
3rd release
0
8
0
0
0
--
fi In Band servo I FI0.C / UOC I L&WB I
(Reverse clutch) FIC (For- WC (High
ward
clutch) clutch)
PARK POSI-
TION
REVERSE POSITION
NEUTRAL POSITION
@ 0 . . Automatic shift
0 '269 8 - -
-38 8 0
@
G3 0 Automatic shift
10 I I Automatic shift
I I I I I I I
:ch is being set in "OFF position. (D, shift is inhibited.) '2: oil pressure is applied to both 2nd "apply" side and 3rd "releasen side of band servo piston. However, brake band does not contract because oil pressure area on the "releasen side is greater than that on the "apply" side. '3: Oil pressure is applied to 4th "apply" side in condition '2 above, and brake band contracts. '4: A/T will not shift to 4th when overdrive control switch is set in "OFF position.
* 1 : O~erate when control
swil
0: Operates. a: Operates
during "progressive" acceleration.
@: Operates but does not affect power transmission. @: Operates when throttle opening is less than specification, but does not affect engine brake. fi: O~erates when throttle opening is less than specification, activating engine brake.

TROUBLE DIAGNOSES
Component Parts Location
[M-AT (Except TCS)]
Control valve uppe:
Line pressure
solenoid Shift solenoid A
Shift solenoid B Overrun clutch
solenoid
Steering switch relay I Ql Shift control unit (Except RB20DE) ?
ATN 1 985D
AT-?

TROUBLE DIAGNOSES
Circuit Diagram
1 Data link connector for CONSULT
I I Vehicle speed sensor 1 I I (Output shaft speed sensor)
Turbine sensor (Exceot RB20DE)
Shifi CRI (M-AT)
65 10 Steering shifl SW (M-AT)
Steering shift main SW
1
Manual mode SW I
Terminal No. in parenthesis ( ) of throttle position sensor and throttle posit~on switch 1s used for RB25DET.
AT-8