1998 NISSAN GT-R lights

TROUBLE DIAGNOSES --- - - - -- -- - -
Fail-safe and Backup Functions
0 The fail-safe function estimates the opening conditions with other input signals and selects safer condi-
tions for the engine (vehicle) control, based on the data previously stored in the control unit, when any of
the critical sensors in the
ECM fails.
The backup function allows the vehicle to be driven, using control signals previously stored in the control G]
unit, even if the critical part of the system fails.
MIL indication
I
Related
sensor
Function
Backup Malfunction
Fail-safehacku p
Fixes the ignition timing, fuel injection pulse width, and
AAC valve opening to the preset values so that the vehicle
can be driven.
ECM
(-TCM)
Mass air
flow
sensor
Engine
coolant
tempera- ture sen-
sor The
microcomputer in the control
unit (CPU) is malfunctioning. MIL lights
up. A'
-- --
Selects the fuel injection pulse width according to the
engine speed and the throttle opening so that the vehicle
can be driven. Fuel injection will be inhibited when the
engine speed exceeded approx.
2,400 rpm. During fail-safe
control, idle speed is controlled to 800
rpm.
Uses the estimated engine coolant temperature (varies with
elapsed time after start) to perform controls so that the
vehicle can be driven normally. The auxiliary electric fan
relay is turned ON. On
RB25DET
model, the turbo pres-
sure control solenoid valve remains OFF.
%R
MIL lights up.
ST
Output voltage dropped below
0.3V while the engine is running.
MIL lights up.
R8 Same as self-diagnostic malfunc-
tion detection conditions.
Heated
owen
sensor Heated oxygen sensor output
voltage exceeded approx.
2V for
predetermined time.
Same as self-diagnostic malfunc-
tion detection conditions. MIL
lights up. d d Inhibits aidfuel ratio feedback control.
Judges the vehicle as of regular specification. Retards the
ignition timing within the knocking range so that the vehicle
can be driven normally.
Determines idle position according to the throttle position
and the engine speed.
Fixes the output to the preset value so that the vehicle can
be driven normally.
On
RB25DET model, the turbo pressure control solenoid
valve remains OFF.
Fail-safe
function Knock
sensor
Throttle position
sensor Same
as self-diagnostic malfunc-
tion detection conditions. MIL
lights up.
Throttle motor
sensor
--
Fixes the throttle motor sensor output to the preset value
by turning the TCS switch
ONIOFF, so that the vehicle can
Same
as self-diagnostic malfunc-
tion detection conditions. MIL
lights up.
be driven normally.
Motor
throttle
switch Same
as
self-diag
nostic
malfunc-
tion detection conditions. Fixes the
TCS switch OFF.
t.. -

TROUBLE DIAGNOSES
Self-diagnosis
(Cont'd)
SELF-DIAGNOSTIC INDICATION ITEMS
I time while the engine is running. I
MIL indication
-
DTC No.
,,
MIL lights up. l2
Self-diagnostic test items
Crankshaft position sen-
sor signal circuit Malfunction (DTC No.)
indication conditions (Malfunction is detected when ...)
lo (POS) signal or 120" (REF) signal is not input for predetermined time
while the engine is running.
Abnohal correlation is detected between 1" (POS) signal and 120" (REF)
sianal.
Mass air flow sensor
signal circuit
MIL lights up.
Engine coo'ant tempera-
"
Mass air flow sensor output voltage is 4.9V or greater for predetermined
time when ignition switch is turned from OFF to ON, or after the engine is
stalled.
Mass air flow sensor output voltage is less than 0.3V for predetermined
Engine coolant temperature sensor output voltage is approx.
4.8V or
greater (open circuit) or less than
0.06V (short circuit) for predetermined
MIL lights up.
-
14
ABS-TCS control unit
circuit JRB25DEl-l
ture sensor signal circuit Throttle control unit detects malfunction
in the system. (Open throttle sen- sor harness, etc.)
Ignition signal circuit
Turbo pressure sensor
signal circuit
[RB25DET]
Overheat
I 1 mined time. I
time-
Vehicle speed sensor
signal circuit
Motor throttle switch sig-
nal circuit
[RB25DET]
TCS/ABS control unit detects malfunction. 1 -
I Knock sensor signal cir-
cuit
- --
No vehicle speed signal is input for predetermined time while the vehicle is
being driven after warm up.
Abnormal correlation is detected between input voltages from the throttle
motor sensor and from the motor throttle switch for predetermined time.
I
MIL lights up. Heated oxygen sensor
signal circuit
Throttle position sensor
signal circuit
No consecutive ignition signal while the engine is running.
Turbo pressure sensor output voltage is approx. 4.8V or greater (open cir-
cuit) or less than
0.06V (short circuit) for predetermined time.
Engine coolant temperature sensor output voltage is approx. 0.35V or less
(sensor normal) for predetermined time.
a Heated oxygen sensor output voltage is approx. 0.2V or greater and less
than approx.
0.4V for predetermined time while the vehicle is being driven
aner warm up. Heated oxygen sensor output voltage is approx. 2V or greater for predeter-
ABS-TCS communica- tion circuit
[RB25DET]
Throttle motor sensor
signal circuit
[RB25DET]
Afr communication cir-
cuit
MIL lights up.
lights
up.
MIL lights up.
NQ malfunction
I a At least one knock sensor indicates the output voltage of approx. 4V or
greater (open circuit) or less than approx.
1V (short circuit).
Throttle position sensor output voltage is approx. 4.7V or greater (open cir-
cuit) or less than
0.06V
(short circuit) for predetermined time while ark/
a Throttle motor sensor input voltage is approx. 418~or greater (open circuit) MIL lights up.
or less than
0.3V
(short circuit) for predetermined time. I
-
MIL liqhts up. neutral position switch is OFF and vehicle speed is 4 kdh or higher.
a Malfunction (openlshort circuit, etc.) is detected in multiplex communication
line between enaine and
TCWABS.
Malfunction is detected in PA communication circuit in ECM (-TCM).
[RBZODE (UB), RB25Dm a Malfunction (open circuit, short circuit, etc.) is detected in multiplex commu-
nication line between ECM and TCM.
[RB25DE1
-
-
No malfunction is detected in all the above circuits. I - - --
Some of the above ~elfaia~nostic test items can cause related malfunctions to be detected in M,
throttle control, and ABS seif-diagnosis when malfunction is detected. Therefore, malfunctions should
also be checked in self-diagnostic tests for systems other than engine.
CONDITIONS TO TURN OFF MALFUNCTION INDICATOR LAMP
Vehicle speed sensor signal circuit: Correct the sensor signal, then drive the vehicle at 4 km/h or higher.
Overheat: Check
for causes of overheat, then erase self-diagnostic results.
Other items: Malfunction indicator lamp turns
OFF when the vehicle returned to normal condition.
HOW TO ERASE SELF-DIAGNOSTIC RESULTS
In Diagnostic Test Mode II, with the engine stopped (ignition switch ON), connect terminals "CHK" and "IGFP
on the data link connector for
2 or more seconds with a suitable harness, then disconnect them.

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.

ANTI-LOCK BRAKE SYSTEM
Self-diagnosis (Cont'd)
MALFUNCTION CODEISYMPTOM CHART
Malfunction code No. Malfunctioning
part ABS warning
lamp
ON
Fail-safe
operation
18 1 Different number of teeth of sensor rotors 1010
2 1
26 I Front left wheel sensor (short-circuiQ.4 1010
- --
22
25
3 1 I Rear wheel sensor (open-circuit) 1010
Front right wheel sensor (open-circuit)
32 Rear wheel sensor (short-circuit)'4 1 0 1 0
Front right wheel sensor (short-circuit)'4
Front left wheel sensor (open-circuit)
41
I Front right outlet ABS solenoid valve and circuit 1010
0 0
0
0
0
0
- -
42
-- - -
46 Front left inlet ABS solenoid valve and circuit 0 1 0
45 Front
left outlet ABS solenoid valve and circuit
55
1 Rear outlet ABS solenoid valve and circuit 1010
Front right inlet ABS solenoid valve and circuit
56
1 Rear inlet ABS solenoid valve and circuit 1010
0
57 1 Power supply (Low or high voltage)*2 I 0 I -'I
0
0
0
I At self-diagno- ( ABS control unit or data link connector for CONSULT is poorly 1 I
61
63
At self-diagno-
I ABS control unit
sis only
ABS
actuator motor or motor relayg3
ABS
actuator relay
No indication
I I ABS control unit1ABS actuator relay is stuck to OFFJABS I Stays ON power supply circuit, ABS actuator relay drive side power sup-
lgnition switch
ply (coil side) circuit, and ABS warning lamp circuit are
short-
circuited./ABS control unit connector is disconnected or poorly
0
0
I
sis only
Ignition switch
ON
I I connected. I I
0
0
connected.
ABS control
unit1Fuse is blown or ABS warning lamp has an
open circuit.
- -- '1: Fail-safe operation does not activate. A signal from ABS control unit suspends ABS control operation. Brakes operate con-
ventionally. After specified power supply voltage resumes, ABS warning lamp goes out, allowing for ABS control operation. '2: The code No. does not indicate a malfunction related to the ABS control unit. Do not replace the ABS control unit even if the code No. appears. '3: The code No. can sometimes appear when the ABS motor ground circuit is loose or disconnected. When it appears, always
check the ground circuit for improper installation.
'4: ABS warning lamp turns on if a wheel or wheels spin for 10 to 80 seconds (depending on the wheel speed) with the vehicle
stuck in snow, ice, or mud. This is a normal condition. 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 krnlh for approx. 1 minute as shown in the self-diagnosis procedure.

TCSlABS SYSTEM
Precautions for Trouble
Diagnosis
After performing trouble diagnosis, be sure to erase trouble stored in memory.
Refer to "CONSULT for
TCS/ABS Control Unit Control System"
(BR-27), "Self-diagnosis for TCSIABS
Control Unit Control System"
(BR-34), "CONSULT for Throttle Control Unit Control System" (BR-37) or
"Self-diagnosis for Throttle Control Unit Control System"
(BR-41).
The concerns that are difficult to duplicate may be caused by faulty electrical connections. Move harnesses
or harness connectors by hand to check if there is any poor mating of connector halves or faulty connec-
tion. 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
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
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.
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:
ABS actuator cannot be disassembled. Do not attempt to disassemble it.
3. Check brake disc rotors and pads for proper operation.
BASIC INSPECTION 2 - Loose power line terminal
Check battery terminals (positive and negative) and battery mounting (ground) for looseness. If necessary,
tighten to specified torque. Check the battery for lower voltage.
BASIC INSPECTION 3 - SLlP indicator lamp, TCS OFF indicator lamp and ABS warning
lamp
Turn ignition switch "ON" to ensure that TCS OFF indicator lamp lights up. If TCS OFF indicator lamp does
not light, check TCS OFF indicator lamp circuit.
Turn ignition switch
"ON" to ensure that SLlP indicator lamp lights
up. If SLlP indicator lamp does not light,
check SLlP indicator lamp circuit.
Turn ignition switch "ON" to ensure that ABS warning lamp lights up. If ABS warning lamp does not light,
check ABS warning lamp circuit.
Check that the SLlP indicator lamp and the ABS warning lamp go off approx.
1 second after the engine
has started. If either of the lamps still remains on, perform the self-diagnosis for TCSIABS control unit
control system and the self-diagnosis for throttle control unit control system.
After driving vehicle at approx. 30
km/h
for approx.
1 minute, check to ensure that the SLlP indicator lamp
and the ABS warning lamp are off. If either of the lamps still remains on, perform the self-diagnosis for
TCS/ABS
control unit control system and the self-diagnosis for throttle control unit control system.
Check that the TCS OFF indicator lamp turns ON and OFF when the TCS OFF switch is turned to
ON
and OFF respectively, with the engine running. If the lamp status does not correspond to the switch
position, check the TCS OFF switch circuit.
Check that the TCS OFF indicator lamp goes off when the engine has started with the TCS OFF switch
OFF. If the TCS
OFF indicator lamp does not go off even 10 seconds after the engine has started, per-
form the self-diagnosis for TCSIABS control unit control system and the self-diagnosis for throttle control
unit control system.
After driving vehicle at approx.
30 kmlh for approx. 1 minute with the TCS OFF switch OFF, check to ensure
that the TCS OFF indicator lamp is off. If the TCS OFF indicator lamp lights up, perform the
self-diagno-
sis for
TCS/ABS
control unit control system and the self-diagnosis for throttle control unit control system.
After performing self-diagnosis procedures, be sure to erase trouble stored in memory.