STC-6
[EPS]
EPS SYSTEM
Revision: June 20062007 Versa
System DiagramUGS000A6
COMPONENTS FUNCTION DESCRIPTION
CAN CommunicationUGS000A7
SYSTEM DESCRIPTION
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.
For details, refer to LAN-47, "
CAN System Specification Chart" .
WGIA0187E
Component parts Function
EPS control unit
(Electric power steering control unit)
Outputs optimum assist torque signal to EPS motor.
Reduces output signals to EPS motor and protects EPS motor and EPS control unit when
using power steering continuously and excessively.
As a fail-safe function, turned off output signal to EPS motor and then enters a manual steer-
ing state, if malfunction is detected in EPS system.
EPS motor Products assist torque by control signal from EPS control unit.
Torque sensor Detects steering wheel turning force and outputs sensor signal to EPS control unit.
Reduction gear Increases motor-produced assist torque by worm gear and transmits it to column shaft.
EPS warning lamp Illuminates if malfunction is detected in electrical system of EPS system.
ECMTransmits the following signals via CAN communication to EPS control unit.
Engine status signal
ABS actuator and electric unit (con-
trol unit) (With ABS)Transmits the following signals via CAN communication to EPS control unit.
Vehicle speed signal
Combination meterTransmits the following signals via CAN communication to EPS control unit.
Vehicle speed signal
TCM (Without ABS)Transmits the following signals via CAN communication to EPS control unit.
Vehicle speed signal
TROUBLE DIAGNOSIS
STC-11
[EPS]
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MA
B
STC
Revision: June 20062007 Versa
EPS Control Unit Input/Output Signal Reference ValuesUGS0007X
SPECIFICATIONS WITH CONSULT-II
CAUTION:
The output signal indicates the EPS control unit calculation date. The normal values will be displayed
even in the event that the output circuit (harness) is open.
*1 : In the front of the value, “L” is displayed at steering left and “R” is displayed at steering right.
*2 : Almost in accordance with the value of “MOTOR SIG”. It is not a malfunction though these values are not accorded when steering
quickly.
*3 : It is not a malfunction, though it might not be corresponding just after ignition switch is turned ON.
*4 : It turns to OFF after waiting for a short period of time.Monitor item (Unit) Content Condition Display value
MOTOR VOL (V)Power supply voltage for
EPS control unitIgnition switch: ON Battery voltage
TORQUE SENSOR (Nm)Steering wheel turning
forceEngine runningSteering wheel: Not
steering (There is no
steering force) 0.00 Nm
Steering wheel: Steer-
ing0 – 8.19 Nm
*1 (The value
is changed according to
steering left or right)
MOTOR SIG (A)Command current to EPS
motorEngine runningSteering wheel: Not
steering (There is no
steering force)0.00 A
Steering wheel: Steer-
ing0 – 65.00 A (The value is
changed according to
steering left or right)
MOTOR CURRENT (A)Consumption current of
EPS motorEngine runningSteering wheel: Not
steering (There is no
steering force)0.00 A
Steering wheel: Steer-
ing0 – 65.00 A
*2 (The value
is changed according to
steering left or right)
VEHICLE SPEED (km/h) or (mph) Vehicle speedVehicle stopped 0 km/h (0 mph)
While drivingApproximately equal to
the indication on speed-
ometer (Inside of ±10%)
*3
WARNING LAMP (ON/OFF)EPS warning lamp condi-
tionEPS warning lamp: ON ON
EPS warning lamp: OFF OFF
DERATING STAT (ON/OFF) Protect overload status Engine runningSteering wheel: Nor-
mal steeringOFF
Steering wheel: Steer-
ing over the stopON
*4
ENGINE STATUS (RUN/STOP) Engine statusEngine stopped
(Engine speed: Less than 400 rpm)STOP
Engine running
(Engine speed: 400 rpm or more)RUN
TROUBLE DIAGNOSIS
STC-13
[EPS]
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STC
Revision: June 20062007 Versa
CONSULT-II Function (EPS)UGS0007Y
FUNCTION
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II SETTING PROCEDURE
Refer to GI-38, "CONSULT-II Start Procedure" .
SELF-DIAG RESULTS MODE
Operation Procedure
1. Perform “CONSULT-II Start Procedure”. Refer to GI-38, "CONSULT-II Start Procedure" .
2. With engine at idle, touch “SELF-DIAG RESULTS”. Display
shows malfunction experienced since the last erasing operation.
NOTE:
When malfunction occurred at the same time, it is dis-
played to a 3 system at the maximum.
The details for “TIME” are as follow:
–“0”: Error currently detected with EPS control unit.
–Except for “0”: Error detected in the past and memorized
with EPS control unit.
Detects frequency of driving after DTC occurs (frequency
of turning ignition switch “ON”).
Display Item List
CAUTION:
If “CAN COMM CIRCUIT [U1000]” is displayed with other DTCs, first perform the trouble diagnosis for CAN communication
line.
How to Erase Self-Diagnostic Results
1. Perform applicable inspection of malfunctioning item and then repair or replace.
Diagnostic test mode Function Reference page
Self-diagnostic results
Self-diagnostic results can be read and erased quickly.STC-13
Data monitorInput/Output data in the EPS control unit can be read.STC-14
CAN diagnostic support monitorThe results of transmit/receive diagnosis of CAN communication can be read.LAN-44
ECU part numberEPS control unit part number can be read.STC-14
SGIA1531E
Item
(CONSULT-II screen terms)Diagnostic item is detected when.... Check item
BATTERY VOLT
[C1601]When the power supply malfunction supplied to EPS control unit is
detected.STC-16, "
DTC C1601
BATTERY VOLT"
TORQUE SENSOR
[C1604]When the torque sensor malfunction assembled in steering column
assembly is detected. STC-19, "DTC C1604
TORQUE SENSOR"
EPS MOTOR
[C1606]When the motor driver malfunction of EPS control unit or EPS motor
malfunction is detected.STC-21, "DTC C1606
EPS MOTOR"
EEPROM
[C1607]When the memory (EEPROM) system malfunction is detected in
EPS control unit.STC-22, "DTC C1607
EEPROM"
CONTROL UNIT
[C1608]When the internal malfunction is detected in EPS control unit.STC-22, "DTC C1608
CONTROL UNIT"
CAN VHCL SPEED
[C1609]When the malfunction is detected in vehicle speed signal received
with CAN communication.STC-23, "DTC C1609
CAN VHCL SPEED"
CAN ENG RPM
[C1610]When the malfunction is detected in engine status signal received
with CAN communication.STC-24, "DTC C1610
CAN ENG RPM"
CAN COMM CIRCUIT
[U1000]When EPS control unit is not transmitting or receiving CAN commu-
nication signal 2 seconds or more.STC-24, "DTC U1000
CAN COMM CIRCUIT"
NO DTC IS DETECTED.
FURTHER TESTING MAY BE
REQUIRED.No NG item has been detected. —
STC-14
[EPS]
TROUBLE DIAGNOSIS
Revision: June 20062007 Versa
2. Turn ignition switch “OFF” to erase memory.
3. Turn ignition switch “ON” and select “SELF-DIAG RESULTS” mode with CONSULT-II.
4. Touch “ERASE” on CONSULT-II screen to erase DTC memory.
CAUTION:
If memory cannot be erased, perform diagnosis.
DATA MONITOR
Operation Procedure
1. Perform “CONSULT-II Start Procedure”. Refer to GI-38, "CONSULT-II Start Procedure" .
2. Touch “DATA MONITOR”.
3. Select from “SELECT MONITOR ITEM”, screen of data monitor mode is displayed.
NOTE:
When malfunction is detected, CONSULT-II performs REAL-TIME DIAGNOSIS. Also, any malfunc-
tion detected while in this mode will be displayed at real time.
Display Item List
EPS CONTROL UNIT PART NUMBER
Display a part number of EPS control unit carried by a vehicle.
Monitor item (Unit) Remarks
MOTOR VOL (V) Power supply voltage for EPS control unit is displayed
TORQUE SENSOR (Nm) Steering wheel turning force detected by torque sensor is displayed
MOTOR SIG (A) Current commanded value to EPS motor is displayed
MOTOR CURRENT (A) Current value consumed by EPS motor is displayed
VEHICLE SPEED (km/h) or (mph) Vehicle speed is displayed from vehicle speed signal with CAN communication
WARNING LAMP (ON/OFF) EPS warning lamp control status is displayed
DERATING STAT (ON/OFF) Protect overload status is displayed
ENGINE STATUS (STOP/RUN) Engine speed is displayed from engine status signal with CAN communication
SGIA1532E
TROUBLE DIAGNOSIS
STC-15
[EPS]
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STC
Revision: June 20062007 Versa
Symptom ChartUGS0008I
If EPS warning lamp turns ON, perform self-diagnosis. Refer to STC-13, "SELF-DIAG RESULTS MODE" .
Symptom Condition Check item Reference page
EPS warning lamp does not turn ON when
ignition switch to “ON”.
(EPS warning lamp check)Ignition switch: ONCAN communication line
STC-26
Combination meter
EPS warning lamp does not turn OFF for
several seconds after starting the engineEngine runningCAN communication line
STC-27
Power supply and ground for
EPS control unit
Torque sensor
EPS motor
Vehicle speed signal
Engine status signal
Combination meter
Steering wheel turning force is heavy or light,
while driving
While driving
Steering wheel turningCAN communication line
STC-29
Vehicle speed signal
Engine status signal
EPS motor
Steering wheel turning force
(Mechanical malfunction)
Unbalance steering wheel turning force and
return between right and left, while driving
While driving
Steering wheel turningWheel alignment
STC-31Steering wheel turning force
(Mechanical malfunction)
Unbalance steering wheel turning force,
while driving (Torque variation)
While driving
Steering wheel turningSteering column intermediate
shaft installation condition
STC-32Steering wheel turning force
(Mechanical malfunction)
TROUBLE DIAGNOSIS FOR SYSTEM
STC-19
[EPS]
C
D
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STC
Revision: June 20062007 Versa
DTC C1604 TORQUE SENSORUGS0008K
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
*: In the front of the value, “L” is displayed at steering left and “R” is displayed at steering right.
EPS CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.
DIAGNOSTIC PROCEDURE
1. CHECK TORQUE SENSOR SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode for “EPS” with CONSULT-II.
3. Check the value of “TORQUE SENSOR”. Refer to STC-11, "
SPECIFICATIONS WITH CONSULT-II" .
Without CONSULT-II
1. Start engine.
2. Check voltage between EPS control unit harness connector M53 terminals 4, 5, 6, 7 and ground. Refer to
STC-12, "
SPECIFICATIONS BETWEEN EPS CONTROL UNIT TERMINALS" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
Monitor item (Unit) Content Condition Display value
TORQUE SENSOR (Nm) Steering wheel turning force Engine runningSteering wheel: Not steering
(There is no steering force)0.00 Nm
Steering wheel: Steering0 – 8.19 Nm*
(The value is changed
according to steering
left or right)
TerminalWire
color Item Condition Data (Approx.)
4 V Torque sensor sub Engine runningSteering wheel: Not steering
(There is no steering force)2.5 V
Steering wheel: Steering1.7 V – 3.3 V
(The value is
changed accord-
ing to steering
left or right)
5 BR Torque sensor power supplyIgnition switch: ON 8 V
Ignition switch: OFF 0 V
6 G Torque sensor main Engine runningSteering wheel: Not steering
(There is no steering force)2.5 V
Steering wheel: Steering1.7 V – 3.3 V
(The value is
changed accord-
ing to steering
left or right)
7 R Torque sensor ground Always 0 V
STC-20
[EPS]
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: June 20062007 Versa
2. CHECK HARNESS AND CONNECTOR
1. Turn ignition switch “OFF”.
2. Disconnect EPS control unit harness connector and torque sensor harness connector.
3. Check continuity between EPS control unit harness connector
(A) M53 terminals 4, 5, 6, 7 and torque sensor harness connec-
tor (B) M63 terminals 1, 2, 3, 4.
Also check harness for short to ground and short to power.
4. Connect EPS control unit harness connector and torque sensor harness connector.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK EPS CONTROL UNIT
Check EPS control unit input/output signal. Refer to STC-11, "
EPS Control Unit Input/Output Signal Reference
Values" .
OK or NG
OK >> GO TO 4.
NG >> Check EPS control unit pin terminals for damage or loose connection with harness connector. If
any items are damaged, repair or replace damaged parts.
4. CHECK DTC
Perform the self-diagnosis, after driving the vehicle for a while.
OK or NG
OK >>INSPECTION END
NG >> Torque sensor is malfunctioning. Replace steering column assembly. Refer to PS-9, "
Removal
and Installation" .
Terminal Continuity
4 – 3
Ye s 5 – 2
6 – 1
7 – 4
SGIA1629E
TROUBLE DIAGNOSIS FOR SYSTEM
STC-21
[EPS]
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STC
Revision: June 20062007 Versa
DTC C1606 EPS MOTORUGS0008L
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
* : Almost in accordance with the value of “MOTOR SIG”. It is not a malfunction though these values are not accorded when steering
quickly.
EPS CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.
DIAGNOSTIC PROCEDURE
1. CHECK EPS MOTOR SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode for “EPS” with CONSULT-II.
3. Check the values of “MOTOR SIG” and “MOTOR CURRENT”. Refer to STC-11, "
SPECIFICATIONS
WITH CONSULT-II" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK EPS MOTOR
1. Turn ignition switch “OFF”.
2. Disconnect EPS control unit harness connector.
3. Check resistance between EPS control unit harness connector
(A) terminals.
4. Connect EPS control unit harness connector.
OK or NG
OK >> GO TO 3.
NG >> EPS motor is malfunctioning. Replace steering column
assembly. Refer to PS-9, "
Removal and Installation" .
Monitor item (Unit) Content Condition Display value
MOTOR SIG (A)Command current to
EPS motorEngine runningSteering wheel: Not steering
(There is no steering force)0.00 A
Steering wheel: Steering0 – 65.00 A
(The value is changed
according to steering left
or right)
MOTOR CURRENT (A)Consumption current of
EPS motorEngine runningSteering wheel: Not steering
(There is no steering force)0.00 A
Steering wheel: Steering0 – 65.00 A *
(The value is changed
according to steering left
or right)
Terminal Wire color Item Condition Data (Approx.)
19 — Motor (+) — —
20 — Motor (−)— —
Connector Terminal Resistance
M60 19 – 20 Approx. 0.1 Ω or less
SGIA1630E