warning NISSAN VERSA 2006 Workshop Service Repair Manual

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-7
[EPS]
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STC
Revision: June 20062007 Versa
TROUBLE DIAGNOSISPFP:00004
Fail-Safe FunctionUGS0008G

If any malfunction occurs in the system, and control unit detects the malfunction, EPS warning lamp on
combination meter turns ON to indicate system malfunction.

When EPS warning lamp is ON, enters a manual steering state. (Control turning force steering wheel
becomes heavy.)
How to Perform Trouble DiagnosisUGS00090
BASIC CONCEPT

To perform trouble diagnosis, it is the must to have understanding about vehicle systems (control and
mechanism) thoroughly.

It is also important to clarify customer complaints before starting
the inspection.
First of all, reproduce the symptoms, and understand them fully.
Ask customer about his/her complaints carefully. In some cases,
it will be necessary to check symptoms by driving vehicle with
customer.
CAUTION:
Customers are not professionals. It is dangerous to make
an easy guess like “maybe the customer means that...” or
“maybe the customer mentions this symptom”.

It is essential to check symptoms right from the beginning in
order to repair malfunctions completely.
For intermittent malfunctions, reproduce symptoms based on
interview with customer and past examples. Do not perform
inspection on ad hoc basis. Most intermittent malfunctions are
caused by poor contacts. In this case, it will be effective to shake
suspected harness or connector by hand. When repairing with-
out any symptom diagnosis, you cannot judge if malfunctions
has actually been eliminated.
PRECAUTIONS FOR TROUBLE DIAGNOSIS

Be sure to check the procedures of the trouble diagnosis in advance. Refer to STC-7, "How to Perform
Trouble Diagnosis" .

Always erase memory after completing trouble diagnosis. Refer to STC-13, "How to Erase Self-Diagnostic
Results" .

Checking continuity and voltage between units, be sure to check connector terminals for disconnection,
looseness, bend, or collapse. Repair or replace applicable part if any non-standard condition is detected.

Be careful not to forcibly extend any connector terminal if a circuit tester is used for the check.

Always confirm the general precautions. Refer to GI-4, "General Precautions" .
INTERVIEW

Complaints vary depending on the person. It is important to clar-
ify the customer's actual remarks.

Ask the customer about what symptoms occur under what con-
ditions. Use the information to reproduce the symptom of con-
firm by vehicle.
SEF 2 33 G
SEF 2 34 G
SEF 9 07 L

TROUBLE DIAGNOSIS
STC-11
[EPS]
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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

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)

STC-18
[EPS]
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: June 20062007 Versa
3. CHECK DTC
Start engine.
Does EPS warning lamp turn OFF?
YES >>INSPECTION END
NO >> Perform self-diagnosis, repair or replace damaged parts. Refer to STC-13, "
SELF-DIAG
RESULTS MODE" .

STC-26
[EPS]
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: June 20062007 Versa
TROUBLE DIAGNOSIS FOR SYMPTOMSPFP:00007
EPS Warning Lamp Does Not Turn ONUGS0008S
SYMPTOM:
EPS warning lamp does not turn ON when ignition switch to “ON”.
DIAGNOSTIC PROCEDURE
1. CHECK SYSTEM FOR CAN COMMUNICATION LINE
Perform self-diagnosis. Refer to STC-13, "
SELF-DIAG RESULTS MODE" .
Is the
“CAN COMM CIRCUIT [U1000]” displayed?
YES >> Perform trouble diagnosis for CAN communication line. Refer to STC-24, "DTC U1000 CAN
COMM CIRCUIT" .
NO >> GO TO 2.
2. 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 3.
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.
3. SYMPTOM CHECK
Check again.
OK or NG
OK >>INSPECTION END
NG >> Replace combination meter. Refer to DI-23, "
Removal and Installation" .

TROUBLE DIAGNOSIS FOR SYMPTOMS
STC-27
[EPS]
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STC
Revision: June 20062007 Versa
EPS Warning Lamp Does Not Turn OFFUGS0008T
SYMPTOM:
EPS warning lamp does not turn OFF for several seconds after starting the engine.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to STC-13, "
SELF-DIAG RESULTS MODE" .
Is any malfunction detected by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 2.
2. CHECK EPS CONTROL UNIT POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”.
2. Disconnect EPS control unit harness connector.
3. Turn ignition switch “ON”. (Do not start engine.)
4. Check voltage between EPS control unit harness connector (A)
terminals and ground.
5. Turn ignition switch “OFF”.
6. Check voltage between EPS control unit harness connector (A)
terminals and ground.
7. Connect EPS control unit harness connector.
OK or NG
OK >> GO TO 3.
NG >> Check the following. If any items are damaged, repair or
replace damaged parts.

60 A fusible link (No. m , located in the fuse and fusible link block). Refer to PG-4, "POWER
SUPPLY ROUTING CIRCUIT" .

10 A fuses (No. 2, located in the fuse block). Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .

Harness for short or open between battery and EPS control unit harness connector M54 termi-
nal 17.

Harness for short or open between ignition switch and EPS control unit harness connector M53
terminal 10.
Connector Terminal Voltage
M53 10 – Ground Battery voltage
M54 17 – Ground Battery voltage
SGIA1626E
Connector Terminal Voltage
M53 10 – Ground Approx. 0 V
M54 17 – Ground Battery voltage
SGIA1627E

TROUBLE DIAGNOSIS FOR SYMPTOMS
STC-31
[EPS]
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STC
Revision: June 20062007 Versa
Unbalance Steering Wheel Turning Force and Return Between Right and LeftUGS0008V
SYMPTOM:
Unbalance steering wheel turning force and return between right and left, while driving.
DIAGNOSTIC PROCEDURE
1. CHECK EPS WARNING LAMP
Confirm EPS warning lamp during engine running.
Does EPS warning lamp turn OFF?
YES >> GO TO 2.
NO >> Go to STC-27, "
EPS Warning Lamp Does Not Turn OFF" .
2. CHECK WHEEL ALIGNMENT
Check wheel alignment. Refer to FSU-6, "
Wheel Alignment Inspection" .
OK or NG
OK >> GO TO 3.
NG >> Adjust wheel alignment. Refer to FSU-6, "
Wheel Alignment Inspection" .
3. CHECK EPS CONTROL UNIT
Check EPS control unit input/output signal. Refer to STC-11, "
EPS Control Unit Input/Output Signal Reference
Va lu e s" .
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. SYMPTOM CHECK
Check again.
OK or NG
OK >>INSPECTION END
NG >> Check the steering wheel turning force because there may be mechanical malfunction. Refer to
PS-6, "
CHECKING STEERING WHEEL TURNING FORCE" .

STC-32
[EPS]
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: June 20062007 Versa
Unbalance Steering Wheel Turning Force (Torque Variation)UGS0008W
SYMPTOM:
Unbalance steering wheel turning force, while driving (Torque variation).
DIAGNOSTIC PROCEDURE
1. CHECK EPS WARNING LAMP
Confirm EPS warning lamp during engine running.
Does EPS warning lamp turn OFF?
YES >> GO TO 2.
NO >> Go to STC-27, "
EPS Warning Lamp Does Not Turn OFF" .
2. CHECK STEERING COLUMN INTERMEDIATE SHAFT
Check the connection between intermediate shaft and the mounting part of steering column assembly and
steering gear assembly. Refer to PS-9, "
COMPONENT" .
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. SYMPTOM CHECK
Check again.
OK or NG
OK >>INSPECTION END
NG >> Check the steering wheel turning force because there may be mechanical malfunction. Refer to
PS-6, "
CHECKING STEERING WHEEL TURNING FORCE" .