1998 NISSAN GT-R engine

TROUBLE DIAGNOSES
Shift Pattern (Cont'd)
RB25DE ENGINE (4AX01 model)
"D" position normal mode
Vehicle speed krnh "D" position SNOW mode
Kickdown area 3
------- Down-shift
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180
Vehicle speed krnh
ATN 1 989C
RB25DET ENGINE (4AX00 model)
"D" ~osition normal mode
Vehicle speed kmfh

TROUBLE DIAGNOSES
Shift Schedule
VEHICLE SPEED WHEN SHIFTING GEARS
RB20DE engine (4AX03 model)
I 1 Vehicle meed km/h
Throttle opening
Full throttle
RB25DE engine (4AX01 model)
Shift pattern
Half throttle
I I Vehicle s~eed km/h
D14D2 I D2*D3 I D34D4 1 D4-1D3 I D3*D2 I D24D1
Normal
Power
Normal
Power
Full throttle 46 - 50
46
- 50
I
Throttle opening Shift pattern
31 - 35
43
- 47
I D2-rD3 I DJdD4 I D4*D3 1 D3*02 1 D24D1
91 - 99
91 - 99
Normal
Power
RB25DET engine (4AX00 model)
62 - 68
84
- 90 149
- 159
149
- 159
50
- 54
50
- 54 I
101 - 109
135
- 143
32
- 36
42
- 46 Half throttle
Throttle opening
VEHICLE SPEED WHEN PERFORMING LOCK-UP
144 - 154
144
- 154
101
- 109
101
- 109
Normal Power
Full throttle
Half throttle
71 - 79
83
- 91
61
- 67
85
- 91
Shift pattern
86 - 94
86
- 94
157
- 167
157
- 167
Vehicle speed krnlh
D14D2 I D2*D3 I D3*D4 I D4*D3 I D3*DZ I D2+D1
Normal
Power
Normal
Power
Closed throttle: Throttle opening
is 118 or below, and idle switch is turned OFF.
Half throttle: Throttle opening is 418.
41 - 45
41
- 45
41
- 45
45
- 51
104
- 112
135
- 143
Engine type
Model No.
speed
D4
speed
6-10
6- 10
151
- 161
151
- 161
-
45 - 49
45
- 49
31
- 35
39
- 43
RB20DE
4AX03
31
- 39
- D,
80 - 88
87
- 95
Lock-up OFF kmh
Lock-up
ON km/h
Lock-up
OFF kmlh
96 - 104
96
- 104
RB25DE
4AX01
34
- 42
- Lock-up ON km/h
40 - 44
40 - 44
37 - 43
45
- 51
-
103 - 111
103
- 111
74
- 80
84
- 90
RB25DET
4AX00
-
-
Closed throttle
Half throttle
Closed throttle
Half throttle
Closed throttle
Half throttle
Closed throttle
Half throttle
6-10
6-10
98
- 106
98 - 106
32
- 38
50
- 56
-- --
40 - 44
40
- 44
6-10
6- 10
167
- 177
167
- 177
111
- 119
133
- 141
23
- 31
101
- 109
44
- 52
120
- 128
35
- 43
110
- 118
-- -- -
161 - 171
161
- 171
63
- 71
98
- 106
25
- 33
104
- 112
48
- 56
118
- 126
38
- 46
107
- 115 59
- 67
121
- 129
55
- 63
128 - 136
52
- 60
103
- 111

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
Stall Test (Cont'd)
JUDGEMENT OF STALL SPEED
5. Depress accelerator pedal gradually while depressing brake
pedal.
6. Read stall speed quickly, and immediately release accelerator
pedal.
CAUTION: Do not
depress accelerator pedal for more than 5 seconds
when testing.
7. Move selector lever to "N" position.
8. Cool down fluid.
CAUTION:
Run engine at idle
for at least one minute.
Specification:
RB20DE 2,300 - 2,500 rpm
RB25DE 2,350 - 2,550 rpm
RB25DET 2,920 - 3,170 rpm
7 Lever position
Stall
speed status Possible causes
Forward
clutch
Forward one-way clutch
Low one-way clutch
Engine and torque converter one-way clutch
7-
0
Line pressure circuit (line pressure drop), forward clutch, low one-way clutch
and forward one-way clutch
Line pressure circuit (line pressure drop), reverse clutch and forward clutch
Forward clutch, low one-way clutch, forward one-way clutch, reverse clutch
and forward clutch
Line pressure circuit (line pressure drop), forward clutch, low one-way clutch,
forward one-way clutch, reverse clutch and
forward clutch
Clutches and brake are normal except high clutch, brake band, and overrun
It
I
0
0 0 Low & reverse brake
Reverse clutch
0: Within stall speed specification
H: Higher than stall speed specification
L: Lower than stall speed specification
0 0 0 clutch. (However, status of high clutch, brake band, and overrun clutch cannc
be confirmed by stall test.)

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.

TROUBLE DIAGNOSES
CONSULT (Cont'd)
DATA MONITOR MODE (M)
1 I Monitor item
I
tem Display ECU
input Main
signals
-
Description Remarks
signals
VHCUS
SE.A'T
[kmlh] or [mph]
I-
Vehicle speed computed from When
racing engine in "Nn or "P" signal of revolution sensor is position
with vehicle stationary,
displayed. CONSULT
data may not indicate
0 kmlh (0 mph).
Vehicle speed computed from Vehicle
speed display may not be
signal of vehicle speed sensor accurate under approx. 10 kmlh
is displayed. (6 mph). It may not indicate 0
kmlh (0 mph) when vehicle is sta-
tionary.
Throttle position sensor signal
voltage is displayed.
AlT fluid temperature sensor
signal voltage is displayed.
Signal voltage lowers as fluid
temperature rises.
Source voltage of TCM is dis-
played.
Engine speed, computed from Engine speed display
may not be
engine speed signal, is
dis- accurate under approx. 800 rpm.
played. It
may not indicate
0 rpm even
when engine is not running.
Turbine revolution computed Error
may occur under approx.
from signal of turbine revolution 800 rpm and will not indicate
0
sensor is displayed. rpm even if engine is not running.
ONIOFF state computed from
signal of overdrive control SW
is displayed.
ONIOFF state computed from
signal of PIN position SW is
displayed.
ONIOFF state computed from
signal of
R position SW is dis-
played.
ONIOFF state computed from
signal of D position SW is dis-
played.
ONIOFF status, computed from
signal of 2 position SW, is dis-
played.
signal of
1 position SW, is dis-
displayed. ASCD is mounted.
ON
... Cruising state
OFF ... Normal running state
Vehicle
speed sensor
1 (All) (Revolution sensor)
Vehicle speed sensor
2 (Meter) VHCUS SE,MTR
[kmk] or
[rnph]
Throttle position sensor
ITHRTLPOS SEN
I ,
AT fluid temperature sensor
PI
FLUID TEMP SE
Battery voltage
A
Engine speed ENGINE SPEED
[rpml
Turbine revolution sensor
TURBINE REV
[rpml
I
Overdrive control switch
OVERDRIVE SW
[ONIOFFJ
I
PIN position switch
PIN POSI SW
[ONlOFF]
R position switch
R POSITION SW
[OWOFF]
I
2 position switch
1
2 POSITION SW
[ONIOFF]
I
D position switch
1 position switch 1 POSITION SW
[ONIOFF]
I
D POSITION SW
[ON/OFF] X
ASCD OD cut signal
ASCD.OD CUT
[ONIOFF]
X
ASCD cruise signal
Status of ASCD OD release
signal is displayed.
ON
... OD released
OFF ... OD not released
ONIOFF status, computed from
signal of
kickdown SW, is dis-
played.
ONIOFF status, computed from
signal of HOLD shift SW, is dis-
played.
ONIOFF status, computed from
signal of closed throttle position
SW, is displayed.
ONIOFF status, computed from
signal of wide open throttle
position SW, is displayed.
ASCD.CRUISE
[ONIOFF]
This
is displayed even when no
ASCD is mounted.
This is displayed even when no
kickdown switch is equipped.
Kickdown
switch
KICKDOWN
SW
[ONIOFq
Wide open throttle position switch X .
X A/T mode switch
t
WIO THRUP-SW
[ONIOFq POWERSHIFT SW
[ONIOFF]
Closed
throttle position switch
, CLOSED THUSW
[ONIOFF]