1998 NISSAN GT-R light

TROUBLE DIAGNOSES
Symptom Matrix Chart (Cont'd)
Engine mechanical-related malfunction I Symptom characteristics and inspection hints
Airffuel
ratio becomes lean.
Air sucked in at oil filler cap
Aidfuel ratio compensation factor becomes higher.
a Intake manifold induction vacuum becomes lower.
I Cracked intake manifold I
Misconnection of canister piping Use an induction vacuum (pressure) gauge for check.
' Common to all air sucking conditions from air intake system.
-
PCV valve stuck open
I Malfunctioning pressure regulator I Various symptoms occur depending on the fuel pressure.
Abnormal noise (peep) may
be heard.
Air/fuel
mixture
Improper gasoline properties Various
symptoms occur depending on the properties.
IEGRiale
stuck open
I
Clogged fuel strainer .
Clogged air cleaner element
Deposits on valve
r
Symptoms vary with the condition how they are clogged. However, the
symptoms tend to occur when the vehicle is driving at high speed and
under high load.
I
Air/fuel ratio becomes lean. Airfluel ratio compensation factor becomes
higher.
Excessive canister purge volume
I
Engine may stall when the accelerator pedal is lightly pressed. (Especially
in summertime.)
Misconnection of high-tension wire Check if the ignition timing
is correct. 1 Improperly adjusted ignition timing 1
Malfunctioning spark plug 1
Corn- I Improper valve contact I Symptoms vary with the degree of contact and the number of cylinders. '
High-tension wire leaks
Distributor
cap leaks Symptoms
vary with the degree of leaks.
Clogged catalytic converter or exhaust sys-
l tem , In many cases, engine stalls and then restarts after a while. I
pression I
Low base idle speed
pressure
Worn piston ring I
Engine may
stall while the vehicle is decelerating or when the power '
steering load or electrical load is applied.
Symptoms vary
with the degree of wear and the number of cylinders.
I
Air conditioner load too heavy I Too much refrigerant in the system. j
Others Dragging
brake
Belt tension too high
1
I Clogged radiator or capacitor I
ArJ load too heavy
Foreign material (vinyl, etc.) in fuel tank Insufficient A/T fluid (FR model)
Symptom tends to occur when fuel level in the tank becomes lower.

TROUBLE DlAGNOSES
Ignition Timing inspection and Adjustment
lnstall a timing light to the ignition timing detection loop (blue)
A3 e Perform "IACV-AAC VALVE ADJ" in "WORK SUPPORT
mode with CONSULT.
/Ci3 Disconnect throttle position sensor harness connector.
w (Above step cancels the idle speed and ignition timing feedbacl
cont rots.)
Cancel "IACV-AAC VALVE ADJ" in "WORK SUPPORl
@ mode with CONSULT.
Connect throttle position sensor harness connector.
Race engine and check that the ignition timing advana
immediately.
With the engine idling, check that the ignition timing and bas1
idle speed is within the specification listed below.
If not within the specifications, loosen the crankshaft positio
sensor mounting bolt, turn the crankshaft position sensor
an
adjust the ignition timing to the specifications. Turning th
crankshaft position sensor counterclockwise advances th
ignition timing.
Unit: BTDCO/rpl
CAUTION:
When idle speed or ignition timing is checked and adjuste
with the throttle position sensor harness
connectc
disconnected, the self-diagnostic results of the throttle
COI
trol unit and the ABS must be erased. To erase the self-dia!
nostic
results, first turn ignition switch OFF, and then start tt
engine. Confirm that the
TCS OFF indicator lamp, 4WD indic
tor lamp, and
ABS indicator lamp are all OFF, then erase tt
self-diagnostic results. This must be done because disco
nection
of the throttle position sensor harness connectc
even for engine adjustment,
will make control units to dete
abnormal status.
RB25DE, RB25DET
15*2/600 Engine type
Ignition timing
RB20DE (VB)
1 O-e2/600

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 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
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
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.

ANTI-LOCK BRAKE SYSTEM
Precautions for Trouble Diagnosis
After performing trouble diagnosis, be sure to erase trouble stored in memory. Refer to "CONSULT' (next
page) or "SELF-DIAGNOSIS"
(BR-15).
As for the concerns that are difficult to duplicate, move harnesses or harness connectors by hand to check
if there is any poor mating of connector halves or faulty connection.
Do not force to open a connector terminal when using a circuit tester for inspection.
Read GI section thoroughly in advance and make sure of all the general precautions.
Basic Inspection
BASIC INSPECTION 1 - Brake fluid level and leakage AT
1. Check brake fluid level in reservoir tank. Replenish brake fluid if necessary.
2. Check for leakage at or around brake piping and ABS actuator. If leakage or seepage is noted, proceed
as follows:
If ABS actuator connectors are loose, tighten to specified torque. Recheck to ensure that leakage is no
longer present.
If flare nut threads at piping connectors or actuator threads are damaged, replace faulty parts with new 87
ones. Recheck to ensure that leakage is no longer present.
If brake fluid leaks through areas other than actuator connectors, wipe off using a clean cloth. Recheck
for leakage or seepage. If necessary, replace faulty parts with new ones.
R8
If brake fluid leaks at or seeps through ABS actuator, wipe off using a clean cloth. Recheck for leakage
or seepage. If necessary, replace
ABS actuator with new one.
CAUTION: HA
ABS actuator cannot be disassembled. Do not attempt to disassemble it.
BASIC INSPECTION 2 - Loose power line terminal
Check battery terminals (positive and negative) and battery mounting (ground) for looseness.
BASIC INSPECTION 3 - ABS warning lamp
1. Turn ignition switch "ON" to ensure that ABS warning lamp lights up for approximately 1 second. If ABS
warning lamp does not light, check ABS warning lamp circuit.
2. After driving vehicle at approx. 30 km/h for approx. 1 minute, check to ensure that ABS warning lamp
remains off. If ABS warning lamp lights, perform self-diagnosis procedures.
3. After performing self-diagnosis procedures, be sure to erase trouble stored in memory.

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.