NISSAN GT-R 1998 Service Manual

TCSfABS SYSTEM
Self-diagnosis for Throttle Control
Unit Control
System (Cont'd)
MALFUNCTION CODE/SYMPTOM CHART
Malfunction
code No. Malfunctioning part Lamp ON
SLIP I TCS OFF I ABS
I I I I
": Even when start signal circuit
or parkheutral position switch circuit is abnormal, TCS operates properly. LED only blinks to
indicate the location of the malfunction. Fail-safe
operation
Throttle position sensor circuit
Throttle motor sensor circuit
Circuit for the communication line between
TCSfABS
con-
trol unit and throttle control unit
Actuator system (Motor circuit is open or throttle motor
intermittently works.)
Start signal circuit
I - I - - -
0
0
0
0
Throttle motor drive system (overcurrent)
Throttle motor relay circuit (shorted)
Throttle motor relay circuit (open)
Throttle motor return spring
I 0 I 0 I I 0 -
0
0
0
0
0
0
0
ParWneutral position switch circuit
Normal
. -
-
-
-
0 0
0
0
0
0
0
-
-
-
-
-
0
0
0
-
-
-
-
-
-

STEERING SYSTEM
SECTION ST
CONTENTS
.......... ELECTRIC SUPER HICAS 2 Control Unit Input/Output Signal Specifications 5 RS ..............................................
....................................................... ............................................................. Pre-inspection -2 Preliminary Check -7
System Description ...................................................... 2 Trouble Diagnosis with CONSULT .............................. 7 M!gJ
....................... Com~onent Parts Location .......................................... 3 Trouble Diagnosis with Self-diagnosis 12
Circuit Diagram ............................................................ 4 Symptom Chalt .......................................................... 14

ELECTRIC SUPER HICAS
INSPECTION BEFORE DRIVING
Check fluid leakage from power steering components (gear, pump, piping, etc.), and check whether the
fluid level is within the proper range.
Check whether tire size and inflation pressure are within the specified limits. Check also whether the
steering wheel is a genuine part, and whether a non-genuine control unit is attached.
Check whether wheel alignment is within the specified limits.
Check whether suspension system is modified, and whether the modification, if any, has increased the
vehicle weight.
INSPECTION DURING DRIVING
Check facts about trouble (what, when, where, who, why and how).
Check whether the engine is running in good condition.
System Description
This system contains two functions for SUPER HICAS: self-diagnosis function and fail-safe function.
For self-diagnosis function, refer to "SELF-DIAGNOSIS PROCEDURE on pages ST-7 and
ST-12.
FAIL-SAFE FUNCTION
If the system detects some error, it halts the normal control and enters the fail-safe mode.
In this event, the system notifies the driver of a malfunction by turning ON the HICAS warning lamp.
The fail-safe mode is canceled when ignition switch
is turned OFF. If, however, the fail-safe mode is caused
by a vehicle speed signal error, it is automatically canceled when the signal is restored before the ignition
switch is turned OFF.
HICAS WARNING LAMP
When the system is in normal condition, HICAS warning lamp is turned ON by switching the ignition ON, and
is turned OFF after engine has started.

ELECTRIC SUPER HICAS
Component Parts Location
EPS solenoid valve
sensor
C I ,n HlCAS motor relay
Front right corner of trunk room

ELECTRIC SUPER HICAS
Circuit Diagram
Sensor 1 signal X E
- cu Sensor 2 signal
CU m f Neutral signal

ELECTRIC SUPER HICAS
Control
Unit Input/Output Signal Specifications
USING CIRCUIT TESTER
Terminal No.
Check item Specification
When control unit is disconnected
: Continuity exists.
Control unit ground circuit
Motor driving output signal
When ignition switch is
ON : Power supply voltage
(In fail-safe mode
: OV)
Motor voltage
When vehicle speed is
0 krn/h : Approx. 4.4 - 6.6V
When vehicle speed is
100 km/h : Approx. 2.4 - 3.6V EPS solenoid driving signal
Battery voltage
I Power supply voltage
Data link connector for CONSULT
(TX) I -
Engine speed signal Measure
tachometer driving signal.
Refer to EC section YECM (TCM) Input/Output Signal
Reference
Value7
.
When ignition switch is ON : Power supply voltage
When ignition switch is OFF
: OV Ignition voltage
Body
/ ground HlCAS waming
lamp When HlCAS warning
lamp is ON
: Approx. OV
When
HlCAS
warning
lamp
is
OFF : Approx. 12V
When ignition switch is ON : Approx. 12V
(In fail-safe mode : Approx. OV)
Output
signal for driving motor relay
Data link connector for CONSULT
(RX) I -
Stop lamp switch signal
(Send brake pedal operation signal to control unit.) When
pedal is depressed : Power supply voltage
When
pedal is not depressed
: OV
Continuity exists.
v Steering angle sensor 2
Steering angle sensor 1
Body
ground When steering wheel
is turned, the voltage changes
between 0 and 5V.
Ground
circuit for rear steering angle sensor
Output signal of rear steering angle sensor
I When neutral : Approx. 2.4V
-
Neutral signal of rear steering angle sensor
When ignition switch is ON
When ignition switch is
OFF
--
When neutral : Appro~. 5V
: Approx. 5V
: Approx. OV Power supply for rear steering angle sensor

ELECTRIC SUPER HlCAS
Control Unit
Input/Output Signal Specifications
(Cont'd)
USING CONSULT
The displayed output signals represent the control unit com-
puted data. If the output circuit (harness) should
be open,
correct values may be displayed.
Monitor item
VHCL SPEED SE
[km/hj
STOP LAMP SW
[ON-OFF] Data monitor
I Condition
Specification
--
STEERING ANG Steering
wheel is turned right Steering angle (degrees) mea-
[R/Ll or left. sured from neutral position
NEUTRAL SIG Steering wheel is in neutral When neutral: ON
[ON-OFF] position
or turned right or left. When
turned (right or left): OFF
Brake pedal operation Check
item
Vehicle is running or driving
wheels are turning.
Steering angle sensor circuit
Approximately
equal to speed-
ometer reading
When pedal is depressed: ON
When pedal is not depressed:
I OFF
In neutral position:
Approx.
2.4V Vehicle
speed sensor circuit
Stop lamp switch circuit
ENGINE SPEED
[r~ml
1"l I Actuator is operating in active I In right lock position:
test. Engine
is running.
Approx. 4.4V
in left lock position:
Approx.
0.4V
Rear steering angle sensing
system
Approximately
equal to tachom-
eter reading
POWER STR SOL
[A1
Wiring
in ECM-HICAS control
unit
MOTOR CURRENT
PI
Vehicle speed is changed from
0 to 100 krnh.
HlCAS RELAY
[ON-OFF]
FAILSAFE
[ON-OFF] At
0 km/h:
Approx. 1.1 0A
At
100 krn/h: Approx. 0.48A
WARNING LAMP
[ON-OFF] System related to power steer-
ing solenoid output signal
RR ST
ANG-VOL
[Vl
MOTOR VOLTAGE
[vl
Actuator is operating in active
test.
Ignition switch is ON or engine
is running.
I Power supply system for
OK
if output current is detected
during operation Motor
and its power supply
system
1 signal from control unit
When ignition
switch is ON: ON
Not in operation HICAS
motor relay
System related to relay driving
Check malfunctioning parts
using self-diagnosis and data
monitor.
Approx.
5V
When warning lamp is ON: ON
When warning lamp is OFF:
OFF
Rear steering angle sensing
system Warning
lamp circuit
Power supply voltage Motor power
supply system
C/U
VOLTAGE
[VI Control unit power supply cir-
cuit
Ignition
switch is ON or engine
is running. Power
supply voltage

ELECTRIC SUPER HICAS
Preliminary
Check
1. Check HICAS actuator for improper attachment and condi-
tions.
Check the actuator for loose fasteners, damage in actuator
body, rods and dust boots, and grease leaks.
@
2. Check suspension system for improper attachment of links and
excessive play in axles.
3. Check all connectors for improper connections. yp 'SU 4. Conduct inspection using self-diagnosis function.
Trouble Diagnosis with CONSULT AT
DESCRIPTION
The trouble diagnoses have four modes: Self-diagnosis, Data B8
monitor, Active test and ECM Part Number modes.
Mode
SELF-D'AGNoSTIC
RESULTS
DATA MONITOR
ACTIVE TEST
ECM PART NUMBER
SELF-DIAG RESULTS I + DATA MONITOR
ACTIVE
TEST
ECM PART NUMBER
u
Function
Displays results of self-diagnosis.
Used to find main causes of trouble,
based on the result of self-diagnosis.
0 Monitors, records and prints the input and
output of
HICAS control unit.
Used to find main causes of trouble,
based on the result of data monitor.
Used to check the operation of actuator
by sending driving signals to it.
a Displays the part number of control unit.
I
SELF-DIAGNOSIS PROCEDURE
$ SELECT DlAG MODE u] r
After connecting CONSULT to data link connector, start the
engine.
Mode switching
Mode is switched simply by
touching the CONSULT
screen.
Touch START (on CONSULT display).
Touch
HICAS.
Touch SELF-DIAG RESULTS.
Refer to CONSULT operation manual
iiHICASJ' for details.
Display
RS
Qkl
The CONSULT screen dis-
plays the data.
EL

ELECTRIC SUPER HICAS
Trouble
Diagnosis with CONSULT (Cont'd)
SELF-DIAGNOSTIC RESULTS MOI -- - - -
Diagnostic item
Diagnostic item is detected when ...
Vehicle speed signal changes rapidly during
running.
I Remarks
VEHICLE SPEED SEN
[SIGNAL
TURN](.b)
I This code appears also when
engine is idling at
1,500 rpm
or faster for more than 10
, seconds; in this case, it does
not indicate abnormality.
Vehicle speed signal is not sensed for more
than
10 seconds while the vehicle is running
at
1,500 rpm of engine speed.
CODE
54
STEERING
ANGLE SEN
[NO ANG
SIG](.a) Steering angle does not change for a while
when vehicle is running at 60
km,h or faster.
Steering angle from neutral position is kept at
60" degrees or more for a certain time when
vehicle is running
at 50 km/h or faster.
Steering angle from neutral position is kept at
30" degrees or more while vehicle travels a
certain distance.
STEERING
ANGLE SEN
[ANG SIG
FIX](.e)
STEERING ANGLE
SEN
[ANG
F1X3O0](-g)
STEERING ANGLE SEN
[NO NEUT
SIG](.b)
No neutral signal (ON signal) is sensed while
vehicle travels a certain distance.
No neutral signal (ON signal) is sensed while
steering wheel is turned more than
360'.
No neutral signal (OFF signal) is sensed while
steering wheel is turned more than
50"
degrees.
STEERING ANGLE
SEN
[NEU SIG
OFF](.c)
STEERING
ANGLE SEN
[NEUT SIG
ON](.d) - - --
a When steering wheel
is turned 360" after the
detection of neutral signal, the neutral signal is
sensed for
a certain period of time.
STEERING ANGLE
SEN
[OFFSET
NEUTJ(.f)
For a certain
period of time, input signal from
main sensor shows abnormality against sensor
power supply voltage.
a When input signal from main sefisor shows
2.5+1 V, input signal from sub-sensor shows
abnormality against sensor power supply volt-
age for a certain period of time.
RR
ST ANGLE SENSOR
[MAIN
SIGNAL](.a)
RR ST ANGLE SENSOR
[SUB
SIGNALJ(.b)
- -
Input signals from main sensor and sub-sen-
sor show more than a certain amount of differ-
ence from each other.
The voltage is higher or lower than the stan-
dard value.
RR
ST ANGLE SENSOR
[OFFSET SIG](-C)
RR ST ANGLE SENSOR
[ABNORMAL
VOL](.d)
r
a Engine speed shows an abnormally low value
for a certain period of time when vehicle is
running at
2 krnlh or faster.
ENG
REV SIGNAL
[ABNORMAL SIGNAL]
a When HlCAS motor relay is ON, motor power
supply voltage shows an abnormally lower
value than ignition power supply voltage.
When control unit keeps motor power OFF, the
motor power voltage shows a non-zero value
for a certain period of time.
MOTOR VOLTAGE
[LOW VOLTAGE](-a)
MOTOR VOLTAGE
[BAD
OBSTRCT](.b)
When a motor current is more than IOA, the
actual output of the motor shows an abnor-
mally low value for a certain period of time.
MOTOR
OUTPUT
[ABNORML
SIG](.a)
- -
MOTOR OUTPUT
[REV CURRENTJ(-C) When motor output is kept ON, a reverse cur-
rent is flowing.

ELECTRIC SUPER HlCAS
Trouble Diagnosis
with CONSULT (Cont'd)
Diagnostic item
MOTOR OUTPUT
[NO
CURRENTJ(.d)
MOTOR OUTPUT
[OVERCU
RRENTl(.e)
MOTOR OUTPUT
[MOTOR
LOCK](.
b)
VEHICLE SPEED SEN
[RAPD SIGN CHANGE21
VEHICLE SPEED SEN
[NO
SIGNAU]
VEHICLE SPEED SEN
[NO SIGNAL31
CONTROL UNIT
[ABNORMAL
1-61
Diagnostic item is detected when ... I Remarks
When motor output is kept OFF, a current is
flowing.
When motor output is kept ON, an overcurrent
is flowing.
Signal from rear steering angle sensor does
not change for a certain period of time while a
motor current of
17A or more is flowing.
When vehicle is running, vehicle speed signal
is not sensed for a certain period of time after
it has changed rapidly.
"VEHICLE SPEED SEN [RPD SIG CHG2J"
has occurred previously, and vehicle speed
signal is not sensed for a certain period of
time.
I
'VEHICLE SPEED SEN [RPD SIG CHG2]" I I
has not occurred previously, and vehicle
speed signal is not sensed for a certain period
of time while the vehicle is running at
1,500
rpm of engine speed.
Control unit is malfunctioning.