ignition NISSAN GT-R 1998 Owner's Guide

TROUBLE DIAGNOSES
ECM (-TCM) InputlOutput Signal Reference
Value (Cont'd)
d
voltages are
Terminal No. Signal name
At idle At
approx. 2,000 rpm
Approx.
12V Approx. 8V
AAC valve control
signal
[RB20DE
(UB), RB25DEl
During 5 sec. after ignition switch tumed ON: Approx. 0.25V 5 sec. after ignition switch turned ON: Battery voltage
When cranking: Approx. 0.25V At idle: Approx. 0.25V Fuel pump relay
control signal - - [RB25DETJ
During 3 sec. after ignition switch tumed ON: Approx.
0.9V
3 sec. after ignition switch tumed ON: Battery voltage
When cranking: Approx. 0.9V At idle: Approx. 0.9V
Approx. 0.9V
Air conditioner
relay control signal Air conditioner
OFF: Battery voltage
Air conditioner ON: Approx. 0.25V
MIL OFF: Battery voltage
MIL ON
RBZODE
(UB), RB25DE: Approx. 0.85V RB25DET Approx. 0.1 V
Malfunction indica-
tor lamp
lgnition switch
(START) signal
Air conditioner
switch signal Approx.
OV (Ignition
switch at START Battery voltage)
Air conditioner OFF: Approx.
4.7V Air conditioner ON: Approx. 0.1 V -
22 (CHK) Check
(Diagnosis
start)
Throttle position
sensor signal
lgnition switch
(IGN) signal CONSULT
connected: Approx. OV CONSULT not connected: Approx. OV
Accelerator pedal released: Approx. OSV Accelerator pedal fully depressed: Approx. 4.2V
(Ignition switch ON, engine not running)
lgnition switch
OFF: Approx. OV lgnition switch ON: Battery voltage Approx.
0.6 - 0.7V
24
(IGN)
Ground Approx.
OV
Power
steering oil
pressure switch
signal Steering
wheel not tumed: Approx. 4.N Steering wheel turned: Approx. OV
26
NOTE: I bove measured values obtained by analog ircuit
tester.

TROUBLE DIAGNOSES
ECM (*TCM) InpuWOutput Signal Reference
Value (Cont'd)
Terminal
No.
41
NOTE: I
Signal name At
idle
rlehicle speed sen-
;or signal
dead lamp switch Light switch OFF: Approx. OV
;ignal
Light switch ON: Battery voltage
gnition power
sup- Ignition switch OFF: Approx. OV
)iY Ignition switch ON: Battery voltage
dle position switch
lB25DET.m
Mottle
opening Accelerator pedal released: Approx.
0.5V
ignal
Accelerator pedal fully depressed: Approx.
4.2V RB25DE.4WD.W
(Ignition switch ON, engine not running) ; RB25D€.AlT,
3R25Dm
Jeutral signal Selector lever in Neutral or in
N or P position: Approx. OV ParWNeutral posi- Selector lever in other positions: Approx. 4.8V
on switch)
:ull switch signal Accelerator pedal released: Approx. OV
?B20DE
(UB), Accelerator pedal fully depressed: Battery voltage
lB25DET-A/Tl (Ignition switch ON, engine not running)
- - - - -- - love voltages are measured values obtained by analog
At approx. 2,000 rpm
IRB20DE
(UB)] When driving at approx. 40 km/h: Approx. 2.4V @I
i ECL 1 7920
[RB25DE, RB25DETI
When driving at approx. 40
kmk: Approx. 2.4V %R
Approx. OV
(When accelerator pedal is depressed)
Approx.
0.N
rcuit tester.

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) 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

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
Control Unit
InputlOutput Signal Specifications
Terminal
No.' Operation
or measurement condition Specifications
Idle switch
(in throttle position switch) After
engine warm-up, release accelerator pedal.
After engine warm-up, depress accelerator
pedal.
PNP switch "1"
position
(c > is used for M-AT.) Battery voltage
@ Approx.
OV
PNP switch
"2"
<"33 position
(c > is used for M-AT.) Selector lever:
"1"
&?"2 position
Selector lever;
Exce~t
"1"
<"2"> ~osition Battery voltage
gz
A~~rox.
OV
PNP switch
"Dm position Selector
lever:
2" <3*> position
Selector lever: Except
"Y 4'3'5 position
Selector lever;
"Dn
position Battery voltage
Approx. OV
Battery voltage
Neutral signal
(PNP switch
"N-P"
position)
- -- Selector lever: Except "Dm position Approx.
OV
PNP switch
"Rn
position RR Selector lever: "Nn, "P" position
Selector lever: Except
"N", "Pn position
Selector lever:
"Rn
~osition
I Selector lever: Except "Rn position 1 Approx. OV
U" " Approx. OV
Approx. 4.7V
. Batterv voltaae ST
I
After engine warm-up, depress accelerator pedal
partially. (Throttle opening: More than 50%) Battery voltage i% Full
switch
(in throttle position switch)
I After engine warm-up, release accelerator pedal. I Approx. OV
Sensor ground
Throttle position sensor
power -- -- - - - I
-- --- Turn iqnition switch ON. Ao~rox. OV @z!.
Shift control signal SB2
(Except RB20DE) Turn ignition switch
ON. Turn ignition switch
OFF.
Approx.
4.5 - 5.5V
Approx. OV
EL
Vehicle speed sensor 1
(Output shaft speed sensor) When vehicle
cruises at 30 kwh (Inspected in AC posi-
tion) More
than approx. 1 V
80
(Voltage increases in
resDonse to vehicle
meed.)
Turbine sensor (Except
RB20DE)
When vehicle parks (Inspected in AC position)
When turbine rotates at approx. 1,000
rpm I Approx. 0.1 V
Approx.
OV
rn fluid temperature sensor 5 I A/l fluid temperature: Approx. 20°C Approx. 1.5V
c
3 V) Battery voltage
Approx. OV .- Y .- c a, -
Afr mode switch (POWER)
(Except M-AT)
A/T fluid temperature: Approx. 80°C ,
AIT mode switch: POWER
A/T mode switch: Except POWER - - - - - - -- Shift control signal DB1
(Except RB20DE)
Shift control signal
DB3
(Except RB20DE) Approx. 0.5V
Overdrive control switch
(Except M-AT) Battery voltage
z g 0
Shift
control signal DB2
(Except RB20DE)
A/T mode switch (SNOW)
(Except TCS) Overdrive
control switch: ON (Contact: OFF)
- .= c .- & .&!
- 5
Stop lamp switch Overdrive
control switch:
OFF (Contact: ON)
CONSULT
(RX) signal Approx.
OV
Battery voltage Appro~. OV
Battery voltage
Approx. OV
.z w .- cJ=- T) .g
2
CONSULT (TX) signal
A/l mode switch: SNOW
A/l mode switch: Except SNOW
Depress brake pedal.
' Release brake pedal.
*: Each number in parenthesis ( ) shows the terminal No. for TCM (RB25DE).
AT-1 1

TROUBLE DIAGNOSES
Control Unit InputlOutput Signal Specifications
(Cont'd)
Terminal
No.' Operation
or measurement condition
Specifications
Total control signal
(multiple communication)
(Except
RB20DE) Refer to
EC section
("ECM.TCM or ECM Input1
Output Signal Reference Value").
I I
I Turn ignition swi?ch ON. I Battery voltage
Power supply (Backup)
Line pressure solenoid - - Turn ignition switch OFF. Battery voltage
r After engine
warm-up, depress accelerator pedal
Line pressure solenoid
(dropping resistor circuit) 5
Approx. OV
w
0.
s
Overrun clutch solenoid After engine
wan-up, release accelerator pedal.
After engine warm-up, release accelerator pedal.
After engine warm-up, depress accelerator pedal
fullv. .- >. .- 5
POWER indicator lamp (4AT)
Dual rnatic
AK waming lamp
(M-AT)
Approx. 1.5 - 3.OV
Approx. 4 - 14V
Approx. OV
When POWER indicator lamp is tumed on (W
mode switch: POWER), or dual matic warn-
ing lamp
is turned on
When
overrun clutch solenoid operates
When overrun clutch solenoid does not operate
Approx.
OV
Battery voltage Approx.
OV
When POWER indicator lamp is tumed off (NT
mode switch:Except POWER), or dual matic A/T Battery voltage
I warning lamp is turned off 1
I When vehicle is locked UD I Approx. 8 - 15V Lock-up solenoid I . .
When vehicle is not locked up I Approx. OV
When shift solenoid A operates
(Driving in 'Dln or
"D,")
When
shift solenoid A does not operate
(Driving in
"D," or "D,")
parenthesis
(
Battery voltage
Approx.
OV
Shift solenoid B
) shows the terminal No. for TCM (RB25DE ).
I
*: Each
When shift solenoid B operates
(Driving in 'Dln or
'D,")
When shift solenoid
B does not operate
(Driving in
"D,"
or
"Dd)
number Battery voltage
Approx. OV

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
Self-diagnosis
DESCRIPTION
If malfunction should occur in electrical systems, turning ignition switch ON lights M mode switch POWER
indicator lamp
(M-AT Dual matic AfT warning lamp) for 2 seconds, and then flashes the indicator lamp for 8 Gc
seconds. If malfunction does not occur, A/T mode switch POWER indicator lamp (M-AT Dual matic A/T warn-
ing lamp) is turned on for
2 seconds upon turning ignition switch ON. To locate and display the malfunction-
ing part, output the trouble information memory and flash
A/T mode switch POWER indicator lamp (M-AT Dual
matic
A/T warning lamp) by inputting self-diagnostic startup signal.
SELF-DIAGNOSIS PROCEDURE
1. Warm up engine.
2. Repeat ON-OFF cycles of ignition switch for more than once, and turn it OFF at last.
3. Move A/T mode switch to AUTO, and turn overdrive control switch to O/D ON.
4. Turn ignition switch ON with selector lever in "Pn position, and ensure POWER indicator lamp is turned on
for
2 seconds.
5. Turn ignition switch OFF.
6. Move selector lever to "D" position.
7. Turn overdrive control switch O/D OFF.
8. Turn ignition switch ON.
9. Move selector lever to "2" position.
10. Turn overdrive control switch OID ON.
11. Move selector lever to "I" position.
12. Turn overdrive control switch O/D OFF.
13. Depress accelerator pedal fully, and release it.
14. Read flashing status of POWER indicator lamp to complete self-diagnosis procedures.
M-AT
1. Warm up engine.
2. Repeat ON-OFF cycles of ignition switch for more than once, and turn it OFF at last.
3. Turn ignition switch ON with selector lever in "P" position, and ensure dual matic PJT warning lamp is turned
on for
2 seconds.
4. Turn ignition switch OFF.
5. Depress brake pedal, release accelerator pedal, and then move selector lever to "D" position.
6. Turn ignition switch ON.
7. Release brake pedal, and move selector lever to "3" position.
8. While depressing brake pedal with left foot, depress accelerator pedal fully with right foot, and move
selector lever to
"2" position.
9. Read dual matic A/T warning lamp indication to complete self-diagnosis procedures.