1998 NISSAN GT-R check engine

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
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
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.

ANTI-LOCK BRAKE SYSTEM
Control Unit InputfOutput Signal Specifications
(Cont'd)
USING CONSULT
Indicated are the control unit computed data. If the output circuit (harness) should be open or short-
circuited, correct values may be displayed.
Check item (Reference)
Data monitor
Display Condition
Monitor
item
Specifications
Vehicle is stationary.
I 0 kdh
FR RH SENSOR
FR LH SENSOR
RR SENSOR
[kdh]
Virtually the same speed
as speedometer (within
+I 0%)
Wheel sensor and circuit
Wheel speed
Vehicle is
drivem'l
Brake pedal is
depressed. Stop lamp switch and
circuit
STOP
LAMP SW
[ON-OFF] Brake pedal status
Brake pedal is not
depressed. OFF
-- --
Actuator (solenoid)
is
activated (at CONSULT
active test),
or
actuator relay is not
activated (with fail-safe
function activated and
engine not running).
FR
RH IN SOL
FR
LH IN SOL
REAR IN SOL
[ON-OFF]
ABS solenoid and circuit
Solenoid status
FR RH OUT SOL
FR
LH OUT SOL
REAR OUT SOL
[ON-OFF]
-- -- - -- -
Actuator (solenoid) is not
activated and actuator
relay is activated (with
vehicle stopped and
engine running).
Actuator relay is acti-
vated (with engine run-
ning).
Actuator relay is not acti-
vated (with fail-safe
function activated and
engine not running).
ABS actuator relay and
circuit
OFF
ON
OFF
ACTUATOR
RLY
[ON-OFF] Actuator
relay status
Motor relay and motor
are activated (at CON-
SULT active test). ABS
motor, motor relay,
and circuit
MOTOR
RLY
[ON-OFF] Motor
relay and motor
status Motor relay and motor
are not activated. OFF
ABS warning lamp and
circuit
- -
Waming lamp ON'2 1 ON
WARNING LAMP
[ON-OFF] ABS
warning lamp sta-
tus
Power supply voltage
provided for control unit -- -
Warning lamp OFF'2 1 OFF
Control unit power sup-
ply circuit - -
BAlTERY VOLT [V] Ignition switch
ON
'1: Tire pressure must be in accordance with specification. "2: ABS warning lamp ON: When the ignition switch is turned ON (before starting the engine) or a malfunction is detected ABS warning lamp OFF: One second after the ignition switch is turned ON (with the system in normal condition)

ANTI-LOCK BRAKE SYSTEM
CONSULT
CONTROL UNIT PART NUMBER
The part number that is shown on the control unit label and CON-
SULT 47850 AAOOO
- SELF-DIAGNOSIS PROCEDURE
Coliect information on the concern from the customer, and then
perform basic inspections.
Turn ignition switch
OFF and connect CONSULT connector to
data link connector for CONSULT on the vehicle.
Start engine and drive vehicle at approx.
30 km/b for approx.
1 minute.
Stop vehicle and touch "START",
"ABS" and "SELF-DIAG
RESULTS" sequentially on the CONSULT screen with engine
running.
If "START" is touched immediately after engine is started
or ignition switch is turned on,
"ABS" may not be dis-
played on "SELECT
SYSTEM" screen. To display "ABS",
repeat the self-diagnosis procedure from the beginning.
Self-diagnosis results are displayed on the screen. (Touch
"PRINT" to print out the self-diagnosis results, if necessary.)
If
"NO FAIL" is displayed, inspect ABS warning lamp. Refer to
the previous page.
Perform appropriate inspection from the self-diagnostic results
mode and repair or replace faulty parts.
Start engine and drive vehicle at approx. 30
km/b for approx.
1 minute.
Recheck to ensure that there is no other malfunction.
Turn ignition switch OFF to prepare for erasing the trouble
stored in memory.
Start engine and touch "START",
"ABS", "SELF-DIAG
RESULTS" and "ERASE" sequentially on the CONSULT
screen to erase the trouble stored in memory.
If the trouble stored in memory is not erased, repeat step
6.
10. Drive vehicle at approx. 30 km/h for approx. 1 minute and then
confirm that ABS warning lamp is
off.

ANTI-LOCK BRAKE SYSTEM
CONSULT (Cont'd) - -
Diagnostic item
CONTROL UNIT --
BAnERY "OLTAGE
[VB-HIGH]
"OLTAGE
[VB- LO
W]
Function of calculation in ABS control unit has failed.
Diagnostic
item is detected when
...
Control unit,
control
unit
power supply
and ground
circuit
Check item
ABS control unit battery voltage
is abnormally high.
ABS control unit battery voltage is abnormally low.
. ABS MOTOR
[LOCK FAILURE] Control
unit
power supply
circuit ABS motor speed is abnormally low. AES motor,
motor relay
and circuit
1 I
'1 : ABS warning lamp turns on if a wheel or wheels spin for I0 to 80 seconds (depending on the wheel speed) with the vehicle
stuck in snow. ice, or mud. This is a normal condition.
'2: After repairing short-circuited sensor, turning ignition switch ON lights up ABS warning lamp. Check that ABS warning lamp
turns
off when the vehicle is driven at approx. 30 krnh for approx. 1 minute as shown in the self-diagnosis procedure. NOTE: If "ABSn is not displayed on "SELECT SYSTEM" screen, check ABS control unit and data link connector circuit, and make sure
of the CONSULT card number.
DATA MONITOR PROCEDURE
Refer to CONSULT Instruction Manual for details on data
monitor function.
1. Turn ignition switch OFF.
2. Connect CONSULT connector to data link connector for CON-
SULT.
3. Turn ignition switch ON.
4. Touch "START' on CONSULT screen.
5. Touch "ABS" on CONSULT screen.
If "START" is touched immediately after engine is started
or ignition switch is turned on,
"ABS" may not be dis-
played on "SELECT SYSTEM" screen. To display "ABS",
repeat the data monitor procedure from the beginning.
6. Touch "DATA MONITORn.
7. Touch "SETTING" to set recording condition.
8. Touch "AUTO TRIG", "LONG TIME" and then "ENTER".
9. Return to "SELECT MONITOR ITEM" screen and touch "CIU
INPUT ITEM", "ALL SIGNALS" or 'SELECTION FROM
MENU". Refer to "DATA MONITOR MODE" on the next page.
10. Touch "START'.
11. Display data monitor.
12. If necessary, sequentially touch "REC START, "REC STOP",
"DATA DISPLAY", "NUMBER PRINT' and "PRINT' to print out
the data.

ANTI-LOCK BRAKE SYSTEM
Self-diagnosis
DESCRIPTION
When a problem occurs in the ABS, the ABS warning lamp on the
instrument panel comes on. To actuate the self-diagnostic results
mode, ground the self-diagnostic check terminal
4 located on the
data
link
connector for
CONSULT. The ABS warning lamp, then,
flashes and indicates the location of the malfunction.
SELF-DIAGNOSIS PROCEDURE
1. Collect information on the concern from the customer, and then
perform basic inspections.
2. Drive vehicle at approx. 30 km/h for approx. 1 minute.
3. Stop vehicle and start diagnosis.
4. Turn ignition switch "OFF'.
5. Ground the self-diagnostic check terminal 4.
6. Turn ignition switch "ON" to start the self-diagnostic results
mode.
CAUTION:
Keep terminal 4 grounded during self-diagnosis.
Do not depress brake pedal. (Self-diagnosis would not
start.)
Do not start engine. (Self-diagnosis would not start.)
7. After 3 or 4 seconds, ABS warning lamp starts blinking to indi-
cate the malfunction code No.
The indication terminates after 5 minutes. Turning the ignition
switch from
"OFF" to "ON" resumes blinking the indication.
8. Verify the location of the malfunction with "MALFUNCTION
CODUSYMPTOM CHART", BR-16. Then make the necessary
repairs.
9. After the malfunctions are repaired, erase the malfunction
codes stored in the control unit. Refer to "HOW
TO ERASE
SELF-DIAGNOSTIC RESULTS" on the next page.
10. Rerun the self-diagnostic results mode to verify that the mal-
function codes have been erased.
11. Disconnect the check terminal from the ground. The self-diag-
nostic results mode is now complete.
12. Drive vehicle at approx. 30 km/h for approx. I minute, and then
check that the ABS warning lamp is off.
HOW TO READ SELF-DIAGNOSTIC RESULTS
(Malfunction codes)
Determine the code No. by observing the time and the fre-
quency that the
ABS warning lamp blinks ON and OFF.
When multiple malfunctions occur at a time, up to three code
numbers can be stored; the latest malfunction will be indicated
first.
The indication begins with the start code No. 12. A maximum
of three code numbers appear in the order of the latest one
first. The indication then returns to the start code No.
12 to
repeat.
The start code No. 12 is only indicated repeatedly when there
is no malfunction.