1998 NISSAN GT-R steering wheel

TROUBLE DIAGNOSES
CONSULT (Cont'd) --
CHECK ITEM (REMEDY)
FUNCTION TEST
ITEM CONDITION
JUDGEMENT
-
PWIST SIGNAL Locked position
Neutral position
Ignition
switch: ON
(Engine running)
Power steering oil pressure switch
circuit is tested when steering
wheel is rotated fully and then set
to a straight line running position. ON
OFF Harness and connector
Power steering oil pressure switch GO
CIRCUIT a Power steering oil pump
I VlAS SN CIRCUIT
0 RB20DE (UB),
RB25DE
The variable air intake system is
diagnosed by checking for opera-
tion of the actuator.
-
SWRL CONT SN
CIRCUIT
0 RB20DE (UB)
The air jet swirl control system is
diagnosed by checking for opera-
tion of the actuator.
-- -- -
a Vehicle speed sensor circuit is
tested when vehicle
is running at
a speed of 10 km/h (6 MPH) or
higher.
After warming up, idle the engine.
Ignition timing is checked by read-
ing ignition timing with a timing
light and checking whether it
agrees with specifications.
Harness and connector 877
Vehicle speed sensor
Vehicle
speed sensor input
signal is greater than 4 krnlh
(2 MPH).
VEHICLE SPEED
SEN CKT Speedometer
RS
Adjust ignition timing (by moving
camshaft position sensor or dis-
tributor)
HA
Camshaft position sensor drive
The
timing light indicates the
same value on the screen.
IGN
TIMING
ADJ
mechanism
la INJECTION SYS (Injector, fuel
pressure regulator, harness or
connector)
IGNITION SYS (Spark plug, igni-
tion coil, power transistor harness
or connector)
VACUUM SYS (Intake air leaks)
Oxygen sensor circuit
Oxygen sensor operation
Fuel pressure high or low
Mass air flow sensor
Air-fuel ratio feedback circuit
(injection system, ignition system,
vacuum system, etc.) is tested by
examining the oxygen sensor out-
put at 2,000
rpm under non-
loaded state. Oxygen sensor COUNT
More
than
5 times during 10 sec-
onds
MIXTURE
RATIO
TEST
- -- /
POWER BALANCE
Injector circuit (Injector, harness or
connector)
Ignition circuit (Spark plug, ignition
coil, power transistor harness or
connector)
Compression
Valve timing
After warming up, idle the engine.
Injector operation of each cylinder
is stopped one after another, and
resultant change in engine rotation
is examined to evaluate combus-
tion of each cylinder. (This is only
displayed for models where a
sequential
multipart fuel injection
system is used.)
D After warming up, idle the engine.
D IACV-AAC valve system is tested
by detecting change in engine
speed when IACV-AAC valve
opening is changed to
0%, 20%
and 80%. Difference
in engine speed is
greater than 25 rpm before
and after cutting off the injec-
tor of each cylinder.
Harness and connector
IACV-AAC valve
Air passage restriction between air
inlet and IACV-AAC valve
IAS (Idle adjusting screw) adjust-
ment
Difference
in engine speed is
greater than 150
rpm
between
when valve opening is at 80%
and at 20%.
IACV-AACN
SYSTEM
ECM PART NUMBER
Part number of the ECM equipped on the vehicle
can be read.
ECM: 2371 0-XXXXX
ECM-TCM: 23740-XXXXX

TROUBLE DIAGNOSES
Symptom Matrix Chart (Cont'd)
Sensor-related problems I Symptom characteristics and ins~ection hints
Open Engine
will not start when either REF signal circuit or POS signal circuit is open.
Neither fuel system nor ignition system outputs control signals.
Crankshaft position sensor
(POS, REF) Instanta-
neous break Symptoms
vary with the break time and the vehicle's driving conditions. Light
shock or surging will occur while the vehicle is being driven, and the engine will
stall at idle speed.
Ring gear crankshaft position
sensor
[RB20DE
(UB)]
Signal
Mass air flow sensor Open
Open
High output
Low output I Aidfuel
ratio becomes lean. Dirty hot wire or air entering the system could be the
cause. No
airfluel ratio compensation
is carried out during lean bum status. Drivability
may be affected.
Enters fail-safe mode. Driving under
2,400 rpm is allowed.
Airlfuel
ratio becomes rich. Black smoke may be noted. Poor contact at the
ground could be the cause.
Engine coolant temperature sen-
sor Open
Open
Opedshort
High resis-
tance
Low resis-
tance
Opedshort
Heated oxygen sensor
I
Airlfuel ratio becomes over-rich.
Same symptom as when signal wire is open.
Enters fail-safe mode. Malfunction indicator lamp comes ON. Ordinary driving is
allowed. Problems tend to occur when engine is cold or engine coolant tempera-
ture
is high.
Detects low engine coolant temperature. Problems tend to occur after engine
warm-up.
Detects high engine coolant temperature. Problems tend to occur when engine is
cold.
Base
aidfuel ratio is used.
lgnition timing is retarded within the knock control range. Lack of power may be
OpedShort
I noted.
Knock sensor lgnition
timing is retarded within the knock control range. Lack of power may be
High
Output
(noted.
Low output
1 lgnition timing may not be retarded when knock is detected.
Vehicle speed sensor
Throttle position sensor
Opedshort
Opedshort
Unstable out-
put
Poor adjust-
ment
Open
Turbo pressure sensor
(TE) Fuel
cut time becomes-shorter, or no fuel cut is observed.
Base idle speed is used. Fuel injection is not increased during acceleration.
AIT shift point changes for AfF vehicles.
Unnecessary cut-in fuel injection could be the cause. Poor contact at the ground
or control unit could be the cause.
ldle judgment is "OFF while idling. Condition returns
normal by turning the igni-
tion switch ON and OFF repeatedly.
Turbo pressure is judged zero. No remarkable malfunction will be detected.
Refrigerant pressure is judged high. ldle speed remains high while the air condi-
tioner is ON.
Refrigerant pressure sensor
Short Refrigerant pressure
is judged low. ldle speed remains low while the air condi-
tioner is ON.
lgnition switch (IGN)
lgnition switch (START)
Air conditioner switch Open
Engine
will not start because neither fuel system nor ignition system outputs con-
trol signals.
Engine starts in normal condition. Engine may not start when temperature is
extremefy
low.
Air conditioner will not operate. No other malfunction will be noted.
Park/neutral
position switch is judged "OFF. Target engine speed for cold engine
in
N or P position is reduced.
ParWneutral position switch is judged
"0N"I Fast Jdle is effective when the engine
is cold and the gear is in other than N and P posrtlons. Vehrcle excessrvely
creeps.
Open
Open
Parklneutral
position
switch
Short
Power steering oil pressure
switch Open
Engine may
stall when the steering wheel is turned while the vehicle is standstill
and the accelerator pedal is lightly pressed, or when the steering wheel is turned
Electrical load switch Short
Open
Open/short
Multiplex communication line
- -- during deceleration. '
Power steering switch is judged 'ON." Value will be compensated constantly.
Idle speed drops so that the engine can stall when electrical load is applied.
Torque reduction control is not performed. Therefore,
shift shock becomes
greater.
- -- -- -- -- Engine will not start because neither fuel system nor ignition system outputs con-
trol signals.
Open
Control unit power supply
- -- - - --- - - - - - O~edshort I Same symptoms as when sensor harness is open.
Sensor ground -- - Poor contact
Water intru-
sion - -- - - - - - -- -- In case of poor contact, the connector fitting may be loose. In case of water
intrusion, the engine stalls and become inoperative for a while. The engine may restart soon in some cases.
Control unit
and connector

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.

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
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
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 HtCAS
Trouble Diagnosis with CONSULT (Cont'd)
DATA MONITOR MODE
1 Monitor item (
Display
Main Menu - -
/ item I item 1
Remarks
VHCL SPEED SE (kmh) 1 0 I 0 I Shows a value calculated from vehicle speed sensor signal.
STEERING ANG After
battery has been disconnected and connected again, an
abnormal value is shown until neutral position
(0") is detected.
NEUTRAL SIG (ON-OFF)
( 0 ( 0 I Shows whether steering wheel is in neutral position (ONIOFF).
STOP
LAMP SW (ON-OFF) I 0 I 0 I Shows whether stop lamp switch is ON or OFF.
ENGINE SPEED Shows the engine speed caicuiated from crankshaft position sen-
sor signal.
1 I I
RR ST ANG.MAI (V) I 0 I 0 I Shows the output voltage from rear steering angle main sensor.
POWER STR SOL
RR
ST
ANG.SUB
(V)
Shows the control
unit's control current for power steering sole-
(')
' ' 1 noid. -- - - -- - -
MOTOR CURRENT (A) I 0 I 0 I shows the control unit's control current for HICAS motor relay.
0
HlCAS RELAY (ON-OFF) / 0 I 0 I Shows whether HlCAS motor relay is ON or OFF.
FAILSAFE
(ON-OFF)
I 0 I 0 I Shows whether fail-safe function is in operation (ONIOFF).
0
WARNING LAMP (ON-OFF) I Q I 0 ) Shows the control unit3 ON-OFF status of HlCAS warning lamp.
Shows the output
voltage from rear steering angle sub-sensor.
Shows the power supply voltage from HICAS control unit to rear
steering angle sensor.
CIU VOLTAGE (V) ( 0 I 0 I Shows the power supply voltage to HICAS control unit.
MOTOR VOLTAGE Shows the power supply voltage
from HICAS
control unit to
HlCAS motor.
- -- - -- VOLTAGE (V) I - I 0 I Shows the measured value by voltage probe.
PULSE Shows the measured
value by pulse probe.
If measurement
is
(mi, Hi and %I 1 - / 0 1 impossible, "#" appears. The "#" mark is shown also on the left of
final data until measurement is completed.