STC-4
[EPS]
SYSTEM DESCRIPTION
Revision: 2007 April2007 M35/M45
Fail-Safe FunctionNGS000DW
When the fail-safe function operate, it controls power steering sole-
noid valve by the engine speed as shown in the figure and maintains
the steering force.
FAIL-SAFE INPUT/CANCEL CONDITIONS
CAUTION:
Fail-safe function is activated when the engine runs at 1,500 rpm or higher for 10 seconds with the vehicle stopped. This is
normal and the fail-safe function is automatically deactivated when a vehicle speed signal of 2 km/h (1.2 MPH) or higher is
input or the ignition switch is turned OFF.
SGIA0411E
Input conditions Cancel conditions
When vehicle runs at an engine speed of 1,500 rpm or higher and no vehicle speed signal
is received for 10 seconds.
A vehicle speed of 2 km/h (1.2 MPH) or
more is input.
Turn the ignition switch ON after turn-
ing it OFF. The continuous vehicle speed signal 30 km/h (19 MPH) or more suddenly drops to less
than 2 km/h (1.2 MPH) within 1.4 seconds.
STC-10
[EPS]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
3. CHECK POWER STEERING CONTROL UNIT POWER SUPPLY CIRCUIT
Turn ignition switch ON, and then check voltage between power
steering control unit harness connector M8 and ground.
OK or NG
OK >> Power supply and ground circuit are normal.
NG >> Power supply circuit open or shorted. Repair or replace
any inoperative parts.
Symptom: The Steering Force Does Not Change Smoothly According to the
Vehicle Speed
NGS000E4
Heavy steering force with the static steering/light steering force during high-speed driving
1. POWER STEERING SOLENOID VALVE SIGNAL INSPECTION 1
1. Start engine.
2. Change the vehicle speed from 0 to 100 km/h (0 to 62 MPH)
slowly, and then check voltage between power steering control
unit harness connector M8 and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 7.
2. POWER STEERING SOLENOID VALVE SIGNAL INSPECTION 2
1. Activate fail-safe function by running the engine speed at 1,500 rpm or higher for 10 seconds with the
vehicle stopped.
2. Change the engine speed to the idling, to approximately 1,600
rpm, and to approximately 3,000 rpm slowly, and then check
voltage between power steering control unit harness connector
M8 and ground.
OK or NG
OK >> GO TO 3.
NG >> GO TO 8.
3. CHECK POWER STEERING SOLENOID VALVE CONNECTOR
Turn ignition switch OFF, disconnect power steering solenoid valve harness connector, and check terminal for
deformation, disconnection, looseness, etc.
OK or NG
OK >> GO TO 4.
NG >> Harness or connector open or shorted. Repair or replace any inoperative parts.Terminal 1 – ground : Battery voltage (Approx. 12 V)
SGIA1232E
Terminal 7 – ground : The voltage has changed from
approximately 4.4 - 6.6 V to
approximately 2.4 - 3.6 V
SGIA1233E
Terminal 7 – ground : The voltage has changed from
approximately 5.5 V to approxi-
mately 2.1 V step-by-step.
SGIA1233E
REAR ACTIVE STEER
STC-15
[RAS]
C
D
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MA
B
STC
Revision: 2007 April2007 M35/M45
4. Supply 6 V voltage by connecting the four 1.5 V batteries in a
series. Connect them to the RAS motor connector (motor side),
and then operate the motor and adjust the rack in the neutral
position (A).
CAUTION:
Do not supply 12 V voltage (battery, etc) to the RAS motor.
NOTE:
For right stroke, connect positive probe to the RAS motor con-
nector terminal 1. For left stroke, connect it to the terminal 2.
5. Install rear wheel steering angle sensor with O-ring to the RAS
actuator assembly. Temporarily tighten the mounting bolts in the specified torque that the sensor can be
moved by hand.
6. Turn and adjust the rear wheel steering angle sensor so as to make each sensor signal of “DATA MONI-
TOR” mode to the following standard with CONSULT-II.
CAUTION:
During DATA MONITOR mode, “MONITORING ERROR” is displayed. But there is not malfunction
in this procedure.
7. Tighten rear wheel steering angle sensor mounting bolts.
8. Perform “ERASE” with CONSULT-II, and then erase the error memory of rear wheel steering angle sen-
sor. Refer to STC-29, "
How to Erase Self-Diagnostic Results" .
9. Perform CONSULT-II “SELF-DIAG RESULTS” again, and then make sure that there is no malfunction.
Refer to STC-28, "
SELF-DIAG RESULT MODE" . Full stroke (B) : 6.8 - 7.2 mm (0.268 - 0.283 in)
STEERING ANG (°) L - 0, R - 0, N - 0
RR ST ANG-MAI (V) Approx. 2.4
RR ST ANG-SUB (V) Approx. 2.4
RR ST ANG-VOL (V) Approx. 5.0
SGIA1240E
STC-16
[RAS]
SYSTEM DESCRIPTION
Revision: 2007 April2007 M35/M45
SYSTEM DESCRIPTIONPFP:00000
ComponentsNGS000E8
RAS (Rear Active Steer) FunctionNGS000E9
A. RAS control unit B. Model following control C. Target vehicle dynamics model
D. Rear wheel steering angle com-
mand value operationE. Rear wheel steering angle servo F. Vehicle speed signal (CAN)
G. Steering angle signal (CAN) H. Vehicle speed sensor I. Steering angle sensor
J. RAS actuator assembly
SGIA1241E
Part name Function
RAS control unit
Calculate the vehicle speed signal from CAN communication and the signals from steering
angle sensor and rear wheel steering angle sensor by a computer, and then control the rear
wheel steering angle.
Fail-safe function is activated when the electrical system is malfunctioning. The output signal
to the actuator is turned OFF during this mode. At that time, the RAS warning lamp illumi-
nates and indicates the system is malfunctioning.
It performs the communication control function with other control units via CAN communica-
tion.
This enables system diagnosis with CONSULT-II.
RAS actuatorThe efficiency of the rear wheel steer improves by locating the electric motor actuator into the
lower link of rear suspension.
Steering angle sensor
Measure the steering angle and send it to RAS control unit via CAN communication.
It is shared with the steering angle sensor for VDC.
Rear wheel steering angle sensor
It sends the rear wheel steering angle status to RAS control unit. The accuracy of rear wheel
steer improves by comparing the vehicle speed signal from CAN communication with the
rear wheel steering angle target value calculated from the wheel angle sensor signal, and it
controls them.
There are 2 types of rear wheel steering angle sensors (main/sub). If one of them is malfunc-
tioning, the other operates the fail-safe mode and stops the control.
RAS warning lamp
It turns on when the fail-safe function is operated and indicates that a RAS control malfunc-
tion has occurred.
It turns on when ignition switch turns on and turns off after the engine is started.
It indicates the suspect system by blinking when performing the self-diagnosis (without CON-
SULT-II).
TROUBLE DIAGNOSIS
STC-27
[RAS]
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STC
Revision: 2007 April2007 M35/M45
STANDARD BY CONSULT-II
CAUTION:
The output signal indicates the RAS control unit calculation data. The normal values will be displayed
even in the event that the output circuit (harness) is open.
CONSULT-II Function (RAS/HICAS)NGS000EG
FUNCTION
CONSULT-II can display each self-diagnostic item using the diagnostic test modes shown following.
Monitor item Condition Reference values
VHCL SPEED SE [km/h] or [mph] Ignition switch ON or engine running Almost in accordance with the speedome-
ter display. It is not a malfunction, through
it might not be corresponding just after
ignition switch is turned ON.
STEERING ANG [°]Turning steering wheel clockwise or coun-
terclockwise.Displays the angle when the steering
wheel turns from the neutral position
ENGINE SPEED [rpm] Engine runningAlmost in accordance with tachometer dis-
play
POWER STR SOL [A]Accelerate the vehicle from 0 to 100 km/h
(0 to 62 MPH)0 km/h (0 MPH): Approx. 1.10 A
100 km/h (62 MPH): Approx. 0.54 A
RR ST ANG-MAI [V]
Perform the ACTIVE TEST and stroke the
actuator (with tires off the ground)Neutral: Approx. 2.4 V
Turn steering wheel to right for full stroke:
Approx. 4.4 V
Turn steering wheel to left for full stroke:
Approx. 0.4 V RR ST ANG-SUB [V]
RR ST ANG-VOL [V]
Ignition switch ON or engine runningApprox. 5 V
C/U VOLTAGE [V]Battery voltage (Approx. 12 V)
MOTOR VOLTAGE [V] Battery voltage (Approx. 12V)
MOTOR CURRENT [A]Perform the ACTIVE TEST and stroke the
actuator.It is normal when there is the current out-
put at stroke
MTR CRNT OPE [A]Turning steering wheel clockwise or coun-
terclockwise while ignition switch is ON or
running the engineNeutral (Steering force is zero and straight-
ahead position): Approx. 0 A
The value is changed according to steering
left or right
RR ANGLE OPE [°]RAS actuator assembly turned full right Approx. 1°
RAS actuator assembly neutral Approx. 0°
RAS actuator assembly turned full left Approx. - 1°
STOP LAMP SW [ON/OFF] Depressing or releasing brake pedalBrake pedal depressed: ON
Brake pedal not depressed: OFF
HICAS RELAY [ON/OFF]
Ignition switch ON or engine runningIgnition switch ON: ON
FAIL SAFE [ON/OFF] Not activated
WARNING LAMP (ON/OFF)RAS warning lamp ON: ON
RAS warning lamp OFF: OFF
Diagnostic test mode Function Reference page
SELF-DIAG RESULTSReceives self-diagnosis results from RAS control unit and
indicates DTCs.STC-28, "
SELF-DIAG
RESULT MODE"
DATA MONITORReceives input/output signals from RAS control unit and
indicates and stores them to facilitate locating cause of mal-
functions.STC-30, "DATA MONI-
TOR MODE"
CAN DIAG SUPPORT MNTRMonitors transmitting/receiving status of CAN communica-
tion.LAN-44, "CAN Diagnos-
tic Support Monitor"
ACTIVE TESTSends command to RAS actuator to change output signals
and check operation of output system.STC-30, "ACTIVE TEST
MODE"
ECU PART NUMBER Displays RAS control unit part number.STC-30, "RAS CONTROL
UNIT PART NUMBER"
TROUBLE DIAGNOSIS
STC-31
[RAS]
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STC
Revision: 2007 April2007 M35/M45
Diagnosis Procedure with Self-Diagnosis Function (Without CONSULT-II)NGS000EL
DESCRIPTION
If a malfunction is detected in the system, the RAS warning lamp turns on and indicates the malfunction. At
that time, fail-safe activates, and then stops the function.
SELF-DIAGNOSIS PROCEDURE
1. Start engine.
2. Turn steering wheel left and right at 20° or more and 5 times or more within 10 seconds. And then depress
the service brake 5 times or more.
3. RAS warning lamp blinks (displays normal/malfunction).
SELF-DIAGNOSIS DISPLAY
RAS warning lamp blinks and displays the self-diagnostic results.
Only DTCs are displayed as the pattern shown in the figure, and
then repeat the display.
If all items are normal, RAS warning lamp blinks at 4 Hz cycle.
SELF-DIAGNOSIS DISPLAY ITEMS
HOW TO ERASE SELF-DIAGNOSIS
If there is the history data for when the fail-safe has activated in the past, erase the memory with CONSULT-II.
Refer to STC-29, "
How to Erase Self-Diagnostic Results" .
CAN CommunicationNGS000EM
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. Refer to LAN-50, "
CAN Sys-
tem Specification Chart" .
SGIA1243E
DTC (warning lamp blinks) Diagnosis item Inspection item
11 RAS control unitSTC-35, "
Inspection 1: RAS Control Unit Malfunction"
12 Motor power supplySTC-35, "Inspection 2: Motor Power Supply System"
13 Motor outputSTC-37, "Inspection 3: RAS Motor Output Malfunction"
21 Vehicle speed signalSTC-38, "Inspection 4: Vehicle Speed Signal"
22 Steering angle signalSTC-39, "Inspection 5: Steering Angle Signal Malfunction"
24 Rear wheel steering angle (main)STC-40, "Inspection 6: Rear Main Signal and Rear Sub Signal
Malfunction"
25 Rear wheel steering angle (sub)STC-40, "Inspection 6: Rear Main Signal and Rear Sub Signal
Malfunction"
26 VDCSTC-43, "Inspection 7: VDC Malfunction"
33 Engine speed signalSTC-44, "Inspection 8: Engine Speed Signal Malfunction"
TROUBLE DIAGNOSIS
STC-33
[RAS]
C
D
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F
H
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B
STC
Revision: 2007 April2007 M35/M45
3. CHECK RAS CONTROL UNIT POWER SUPPLY CIRCUIT
Turn ignition switch ON, and then check voltage between RAS con-
trol unit harness connector B476 and ground.
OK or NG
OK >> Power supply and ground circuit are normal.
NG >> Power supply circuit open or shorted. Repair or replace
any inoperative parts.
Trouble Diagnosis ChartNGS000EP
SELF-DIAGNOSIS
Terminal 27 – Ground : Battery voltage (Approx. 12 V)
SGIA1245E
Item
Reference Self-diagnosis function CONSULT-II
DTC
(warning
lamp blinks)Diagnosis item Diagnosis item
11 RAS control unitCONTROL UNIT [ABNORMAL1] [C1900]
STC-35
CONTROL UNIT [ABNORMAL2] [C1901]
CONTROL UNIT [ABNORMAL3] [C1905]
CONTROL UNIT [ABNORMAL5] [C1906]
CONTROL UNIT [ABNORMAL4] [C1907]
CONTROL UNIT [ABNORMAL7] [C1908]
CONTROL UNIT [ABNORMAL6] [C1909]
CONTROL UNIT [ABNORMAL8] [C1922]
CONTROL UNIT [ABNORMAL5] [C1927]
CONTROL UNIT [ABNORMAL9] [C1928]
12 Motor power supplyMOTOR VOLTAGE [LOW VOLTAGE] [C1911]
STC-35
MOTOR VOLTAGE [BAD OBSTRCT] [C1912]
13 Motor outputMOTOR OUTPUT [ABNORMAL SIG] [C1913]
STC-37
MOTOR OUTPUT [REV CURRENT] [C1902]
MOTOR OUTPUT [NO CURRENT] [C1903]
MOTOR OUTPUT [OVERCURRENT] [C1904]
MOTOR OUTPUT [MOTOR LOCK] [C1910]
21 Vehicle speed signal VEHICLE SPEED SEN [NO SIGNAL] [C1919]STC-38
22 Steering angle signalSTEERING ANGLE SEN [NO CHANGE] [C1923]
STC-39STEERING ANGLE SEN [NO NEUT STATE] [C1924]
STEERING ANGLE SEN [NO SIGNAL] [C1920]
STEERING ANGLE SEN [C1926]
STC-34
[RAS]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
DIAGNOSIS CHART BY SYMPTOM
24 Rear wheel steering angle (main)RR ST ANGLE SENSOR [MAIN SIGNAL] [C1915]
STC-40RR ST ANGLE SENSOR [ABNORMAL VOL] [C1914]
RR ST ANGLE SENSOR [OFFSET SIG1] [C1917]
RR ST ANGLE SENSOR [OFFSET SIG2] [C1918]
25 Rear wheel steering angle (sub)RR ST ANGLE SENSOR [SUB SIGNAL] [C1916]
RR ST ANGLE SENSOR [ABNORMAL VOL] [C1914]
RR ST ANGLE SENSOR [OFFSET SIG1] [C1917]
RR ST ANGLE SENSOR [OFFSET SIG2] [C1918]
26 VDC VDC [C1929]STC-43
33 Engine speed signal MOTOR OUTPUT [C1921]STC-44
— CAN COMM CIRCUIT [U1000]
STC-44
— CONTROL UNIT (CAN) [U1010]
Symptom Reference
It is not entering the self-diagnosis mode.STC-32, "
BASIC INSPECTION 3: RAS CONTROL UNIT POWER
SUPPLY CIRCUIT AND GROUND CIRCUIT INSPECTION"
STC-45, "Inspection 10: Stop Lamp Switch Harness"
STC-46, "Inspection 11: RAS Warning Lamp Harness"
RAS warning lamp does not turn on with ignition switch ON.STC-32, "
BASIC INSPECTION 3: RAS CONTROL UNIT POWER
SUPPLY CIRCUIT AND GROUND CIRCUIT INSPECTION"
STC-46, "Inspection 11: RAS Warning Lamp Harness"
RAS warning lamp turns on with ignition switch ON. It does not
turn off even if the engine is started.STC-32, "
Basic Inspection"
STC-28, "SELF-DIAG RESULT MODE"
STC-31, "Diagnosis Procedure with Self-Diagnosis Function
(Without CONSULT-II)"
RAS warning lamp may turn on after the engine is started.STC-28, "SELF-DIAG RESULT MODE"
The steering force does not change smoothly according to the
vehicle speed.STC-47, "Diagnosis Chart by Symptom 2"
Noise
STC-28, "SELF-DIAG RESULT MODE"
STC-31, "Diagnosis Procedure with Self-Diagnosis Function
(Without CONSULT-II)"
STC-14, "INSPECTION AFTER DISASSEMBLY"
Malfunction other than aboveSTC-47, "Diagnosis Chart by Symptom 1"