NISSAN GT-R 1998 Manual Online

ANTI-LOCK BRAKE SYSTEM
Fail-safe Function
If any malfunction is detected in the system, the ABS warning lamp
in the instrument panel is turned on with the ABS deactivated and
the vehicle's brake system reverts to normal operation.
System Diagram
ABS control uni: Actuator
Front lefl wheel sensor
Rear wheel Sensor Front
right inlet solenoid valve 1 I -
L ' Data ltnk connector
for CONSULT
Front right outlet solenold valve
Front lett rnlet solenoid vJve
Front left cutlet solenoid valve
r i Rear inlet solenold valve
Contrd
circuit I
Rear outlet solenoid valve
-A Motor (motor relay)
-- Actuator relay
Faii-safe
circuit
TrO~ble
diagnos~s
circuit ABS
warning lamp

ANTI-LOCK BRAKE SYSTEM
Circuit Diagram
To combination meter
I Stop lamp SW
I ABS wamlng lamp i
stop lamp 9
Wheel
sensor i connector &
FL
FR
Rea Motor relay
. FIL - 8 30A
I 11: Actuator
relay I
ABS CIU
To data link connector for CONSULT 1 RX "8 - 12
FR OUT SN fm
Rear OUT SN
Rear IN SN
27 10 ABS actuator :
ABS actuator connector
-
ABS CN connector

ANTI-LOCK BRAKE SYSTEM
Component
Parts Location
Master
Front
Booster /'
ear wheel sensor
@ ABS control unit
right wheel sensor
Front left wheel
sens&
-/
a ABS actuator
Front right wheel sensor connector
.. .
!a In the instrument panel on
LH side of engine compartment dR/Y A

ANTI-LOCK BRAKE SYSTEM
ABS control unit connector
Terminal No.
Control Unit InputlOutput Signal Specifications
USING CIRCUIT TESTER
To perform the following inspection, the ignition switch should be
turned
ON with ABS control unit connector and actuator connector
properly connected.
Item Specifications*l
Battery Ignition switch ON: Battery voltage (Approx. 12V)
Brake pedal is depressed: Battery voltage (Approx. 12V)
Stop lamp signal
Brake pedal is not depressed: Less than approx.
2V
ABS motor is running
ABS motor relay (in
CONSULT active test mode): Less than approx.
2V
ABS motor is stopped: Battery voltage (Approx.
12V)
Actuator relay is activated (with engine running): Less than approx. 2V
Actuator relay Actuator
relay is not activated (with fail-safe function activated and engine
not running): Battery voltage (Approx. 12V)
Actuator relay is activated (with engine running): Battery voltage (Approx.
Actuator relay 1 2V)
monitor Actuator
relay is not activated (with fail-safe function activated and engine
not running): Approx. OV
Front
right inlet
Actuator is activated (in CONSULT active test mode), or actuator relay is
solenoid not activated (with fail-safe function activated and engine not running):
Rear inlet solenoid Approx. OV
Front
left inlet Actuator
is not activated and actuator relay is activated (with vehicle
solenoid stopped
and engine running): Battery voltage (Approx. 12V)
ABS motor is running (in CONSULT active test mode): Battery voltage
ABS motor monitor (Approx. 12V)
ABS motor is stopped (with ignition switch
ON): Approx. OV
ABS warning lamp
ON'2:
Approx. OV
ABS warning lamp
ABS warning lamp
OFF'2:
Battery voltage (Approx. 12V)
Front right wheel
sensor Wheels are turning (Approx. 30
krn/h)*3: Pulse generates.
Front: Approx. 200
Hz
sensor
Rear: Approx. 400 Hz
Front right outlet
Actuator is activated (in CONSULT active test mode), or actuator relay is
not activated (with fail-safe function activated and engine not running):
Rear outlet
sole-
Approx. OV
I lUlU / Actuator is not activated and actuator relay is activated (with vehicle Front left Outlet stopped and engine running): Battery voltage (Approx. 12V)
solenoid
'1:e
to
tooen
a connector terminal when
using a circuit tester for inspection. Control
I
unit
power
supply circuit
ST
Stop lamp switch
and circuit
ABS motor, motor
R8
relay and circuit
ABS actuator relay
and circuit
pL
ABS warning lamp
and circuit, ABS
actuator relay
SD monitor circuit
ABS solenoid and
circuit
ABS motor monitor
circuit
ABS warning lamp
and circuit
Wheel sensors and circuit
ABS solenoid and
circuit
'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) *3: Tire pressure must be in accordance with specification.

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
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
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)
SELF-DIAGNOSTIC RESULTS MODE
Diagnostic item I Diagnostic item is detected when ... I Check item
FR RH SENSOR
[OPEN] Circuit
for front right wheel sensor is open. Or an abnormally high input voltage is
entered due to short to battery.
FR LH SENSOR
[OPEN]
- -- -- - - - ---
Circuit for front left wheel sensor is open. Or an abnormally high input voltage is entered
due to short to battery.
1
FR RH SENSOR
[SHORTJ'I
, '2
REAR SENSOR
[OPEN] Circuit
for rear wheel sensor is open. Or an abnormally high input voltage is entered due
to short to battery.
1
FR LH SENSOR
[SHORT] Front
right wheel sensor is short-circuited or shorted to ground, or gap between the
wheel sensor and the sensor rotor is large. An abnormally low
input voltage is entered
and input signal is abnormal.
Front left wheel sensor is short-circuited or shorted to ground, or gap between the wheel
sensor and the sensor rotor is large. An abnormally low input voltage is entered and
input signal is abnormal. Wheel
sen-
sor and cir-
cuit
REAR SENSOR
[SHORT
11'1, '2
Rear wheel sensor is short-circuited or shorted to ground, or gap between the wheel
sensor and the sensor rotor is large.
An abnormally low input voltage is entered and
input signal is abnormal.
FR RH IN ABS SOL
[OPEN]
FR LH IN ABS SOL
[OPEN] Circuit
for front right inlet solenoid valve is open, or an output voltage is much lower than
the specified value due to short to ground.
Circuit for front left inlet solenoid valve is open, or an output voltage is much lower than
the specified value due to short to ground.
REAR IN ABS SOL
[OPEN] Circuit
for rear inlet solenoid valve is open, or
an output voltage is much lower than the
specified value due to short to ground.
FR RH IN ABS SOL
[SHORT] Circuit
for front right inlet solenoid valve is shorted, or an output voltage is much higher
than the specified value due to short to battery.
FR LH IN ABS SOL
[SHORT] Circuit for front
left inlet solenoid valve is shorted, or an output voltage is much higher
than the specified value due to short to battery.
REAR IN ABS SOL
[SHORTJ
FR RH OUT ABS SOL
[OPEN]
FR
LH OUT ABS SOL
[OPEN]
REAR OUT ABS SOL
[SHORT]
FR RH OUT ABS SOL
[SHORT]
FR LH OUT ABS SOL
[SHORT]
RWR OUT ABS SOL
[SHORT] Circuit for
rear inlet solenoid valve is shorted, or an output voltage is much higher than
the specified value due to short to battery.
Circuit for front right outlet solenoid valve
is open, or an output voltage is much lower
than the specified value due to short to ground.
Circuit for front left outlet solenoid valve is open, or an output voltage is much lower than
the specified value due to short to ground.
Circuit for rear outlet solenoid valve is open, or an output voltage is much lower than the
specified value due to short to ground.
Circuit for front right outlet solenoid valve
is shorted, or an output voltage is much higher
than the specified value due to short to battery.
Circuit for front left outlet solenoid valve is shorted, or an output voltage is much higher
than the specified value due to short to battery.
- -- -- - - Circuit for rear outlet solenoid valve is shorted, or an output voltage is much higher than
the specified value due to short to battery.
ABS MOTOR
[ON FAILURE]
ABS MOTOR
[OFF FAILURE] ABS
sole-
noid
and cir-
cuit
ABS ACTUATOR RELAY
[ON FAILURE]
ABS ACTUATOR RELAY
[OFF FAILURE] ABS
motor turns ON when control unit sends OFF signal. ABS motor circuit is open or
shorted to ground.
ABS motor turns OFF when control unit sends ON signal. Relay control wire is broken. ABS motor,
motor relay
and circuit
ABS actuator relay tums ON when control unit sends OFF signal. Actuator relay is
short-
circuited to ground.
ABS actuator relay tums OFF when control unit sends ON signal. Relay control wire is
broken. ABS
actuator
relay and
circuit

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
CONSULT (Cont'd)
DATA MONITOR MODE
MONITOR ITEM I CONDITION
FR RH SENSOR
FR
LH SENSOR
RR SENSOR Drive vehicle.
(Each wheel is rotating.)
STOP LAMP SW Turn
ignition switch ON and
depress brake pedal.
FR RH
IN SOL
FR RH OUT SOL
FR
LH IN SOL
FR LH OUT SOL
REAR IN SOL
REAR OUT SOL Ignition
switch is turned ON or
engine is running.
ACTUATOR RLY
MOTOR RLY
Ignition switch is turned ON or
engine is running.
WARNING LAMP
BATTERY VOLT
I
VOLTAGE Indicates
the voltage mea-
sured with a voltage probe.
PLS WIDTH-H
I
Refer to CONSULT Instruction
Manual.
NlSSAN
CONSULT
START I --
1 SUB MODE BR455C
$ SELECT SYSTEM 0-
ENGINE
A/T
I - ABS I
SPECIFICATION
Displays computed vehicle speed from wheel sensor signal.
Almost the same speed as speedometer.
Depress the pedal: ON
Release the pedal: OFF
EC ;
Operating conditions for each solenoid valve are indicated. ABS is AT '
not operating: OFF
Displays ON/OFF condition of ABS actuator relay.
When turning ignition switch ON,
ABS actuator relay
is operated. 2
ABS is not operating: OFF
ABS
is operating: ON
Warning lamp is turned on: ON
R8 $
Warning lamp is turned off: OFF
Power supply voltage for control unit
~~~~
ACTIVE TEST PROCEDURE
When conducting Active test, vehicle must be stationary.
Confirm that brakes have been bled completely.
When ABS warning lamp stays on, never conduct Active test.
Turn ignition switch OFF.
Connect CONSULT to Data Link Connector for CONSULT.
Start engine.
Touch "START' on CONSULT screen.
Touch
"ABS".