2008 NISSAN TIIDA stc

PS-6
< SERVICE INFORMATION >
STEERING WHEEL
STEERING WHEEL
On-Vehicle Inspection and ServiceINFOID:0000000001703859
CHECKING CONDITION OF INSTALLATION
• Check installation conditions of steering gear assembly, front suspension assembly, axle and steering col-
umn assembly.
• Check if movement exists when steering wheel is moved up and down, to the left and right and to the axial
direction.
• Check steering gear assembly mounting bolts and nuts for looseness. Refer to PS-12, "
Removal and Instal-
lation" .
CHECKING STEERING WHEEL PLAY
• Turn steering wheel so that front wheels come to the straight-ahead position. Start engine and lightly turn
steering wheel to the left and right until front wheels start to move. Measure steering wheel movement on the
outer circumference.
• When the measurement value is outside the standard value, check backlash for each joint of steering col-
umn assembly and installation condition of steering gear assembly.
CHECKING NEUTRAL POSITION STEERING WHEEL
• Make sure that steering gear assembly, steering column assembly and steering wheel are installed in the
correct position.
• Perform neutral position inspection after wheel alignment. Refer to RSU-2, "
Precaution for Supplemental
Restraint System (SRS) "AIR BAG" and "SEAT BELT PRE-TENSIONER"" .
• Set vehicle to the straight-ahead position and confirm steering wheel is in the neutral position.
• Loosen outer socket lock nut and turn inner socket to left and right equally to make fine adjustments if steer-
ing wheel is not in the neutral position.
CHECKING STEERING WHEEL TURNING FORCE
1. Park vehicle on a level and dry surface, set parking brake.
2. Start engine.
3. Check steering wheel turning force when steering wheel has
been turned 360° from neutral position using suitable tool as
shown.
4. If steering wheel turning force is out of the specification, refer to
STC-6, "
How to Perform Trouble Diagnosis" .
CHECKING FRONT WHEEL TURNING ANGLE
Steering wheel axial end play : 0 mm (0 in)
Steering wheel play : 0 - 35 mm (0 - 1.38 in)
Steering wheel
turning force: Less than 36 N (3.7 kg-f, 8.2 lb-f)
WGIA0180E

PS-10
< SERVICE INFORMATION >
STEERING COLUMN
8. Remove bolt of intermediate shaft (upper side), and then remove intermediate shaft from steering column
assembly.
9. Remove steering column assembly mounting nuts, and then remove steering column assembly from vehi-
cle.
10. Remove bolt of intermediate shaft (lower side), and then remove intermediate shaft from vehicle.
11. Remove screws of bracket and EPS control unit, and then remove bracket and EPS control unit from
steering column assembly.
INSPECTION AFTER REMOVAL
• Check each part of steering column assembly, EPS control unit and intermediate shaft for damage and .
replace as necessary.
• Measure the length “L” as shown, if vehicle has been involved in a
minor collision. Replace steering column assembly (with motor,
reduction gear, sensor) if outside the standard.
• Check tilt mechanism for damage or other malfunctions. Replace
steering column assembly (with motor, reduction gear, sensor) as
necessary.
• Measure steering column assembly rotating torque using Tool. Replace steering column assembly (with
motor, reduction gear, sensor) if outside the standard.
INSTALLATION
Installation is in the reverse order of removal.
• Installation is in the reverse order of removal. For tightening torque, refer to "COMPONENT".
• When tightening bolt (intermediate shaft lower side), tighten it by hand first, and make sure there is no feel-
ing of sticking or galling before final tightening.
CAUTION:
Insert bolt in the proper direction. (Do not insert it from the other side.)
• When connecting intermediate shaft upper side (1) and column
shaft, make sure the bolt is securely seated in groove (A) of col-
umn shaft (A) before final tightening.
INSPECTION AFTER INSTALLATION
• Rotate steering wheel to check for decentered condition, binding, noise or excessive steering effort.
• After installing steering column assembly, perform self-diagnosis with CONSULT-II to ensure correct opera-
tion. Refer to STC-11, "
CONSULT-III Function (EPS)". Steering column
length “L”Minimum 462.1 mm (18.19 in)
Nominal 464.1 mm (18.27 in)
Maximum 466.1 mm (18.35 in)
Tool number : ST3127S000 (J-25742-1)
Rotating torque : 0 - 2.1 N·m (0 - 0.21 kg-m, 0 - 18 in-lb)
SGIA1293E
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STC-1
STEERING
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SECTION STC
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CONTENTS
STEERING CONTROL SYSTEM
EPS
SERVICE INFORMATION ............................
2
PRECAUTIONS ...................................................2
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ...................................................................
2
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect .....................................
2
Service Notice or Precaution for EPS System ..........2
EPS SYSTEM ......................................................4
System Description ...................................................4
Schematic .................................................................5
CAN Communication .................................................5
TROUBLE DIAGNOSIS ......................................6
Fail-Safe Function .....................................................6
How to Perform Trouble Diagnosis ...........................6
Component Parts Location ........................................7
Wiring Diagram - EPS - .............................................8
EPS Control Unit Input/Output Signal Reference
Value .........................................................................
9
EPS Terminal and Reference Value ........................10
CONSULT-III Function (EPS) ..................................11
Symptom Chart ........................................................13
TROUBLE DIAGNOSIS FOR SYSTEM ............14
DTC C1601 BATTERY VOLT ..................................14
DTC C1604 TORQUE SENSOR .............................15
DTC C1606 EPS MOTOR .......................................16
DTC C1607 EEPROM .............................................17
DTC C1608 CONTROL UNIT ..................................17
DTC C1609 CAN VHCL SPEED .............................18
DTC C1610 CAN ENG RPM ...................................19
DTC U1000 CAN COMM CIRCUIT .........................19
Component Inspection .............................................19
TROUBLE DIAGNOSIS FOR SYMPTOMS ......21
EPS Warning Lamp Does Not Turn ON ..................21
EPS Warning Lamp Does Not Turn OFF ................21
Steering Wheel Turning Force Is Heavy or Light .....22
Unbalance Steering Wheel Turning Force and Re-
turn Between Right and Left ....................................
23
Unbalance Steering Wheel Turning Force (Torque
Variation) .................................................................
24

STC-2
< SERVICE INFORMATION >[EPS]
PRECAUTIONS
SERVICE INFORMATION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000001703869
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal
injury caused by unintentional activation of the system. For removal of Spiral Cable and Air Bag
Module, see the SRS section.
• Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or har-
ness connectors.
Precaution Necessary for Steering Wheel Rotation After Battery Disconnect
INFOID:0000000001703870
NOTE:
• This Procedure is applied only to models with Intelligent Key system and NVIS/IVIS (NISSAN/INFINITI
VEHICLE IMMOBILIZER SYSTEM - NATS).
• Remove and install all control units after disconnecting both battery cables with the ignition knob in the
″LOCK″ position.
• Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If DTC is detected, perform trouble diagnosis according to self-diagnostic results.
For models equipped with the Intelligent Key system and NVIS/IVIS, an electrically controlled steering lock
mechanism is adopted on the key cylinder.
For this reason, if the battery is disconnected or if the battery is discharged, the steering wheel will lock and
steering wheel rotation will become impossible.
If steering wheel rotation is required when battery power is interrupted, follow the procedure below before
starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables.
NOTE:
Supply power using jumper cables if battery is discharged.
2. Use the Intelligent Key or mechanical key to turn the ignition switch to the ″ACC″ position. At this time, the
steering lock will be released.
3. Disconnect both battery cables. The steering lock will remain released and the steering wheel can be
rotated.
4. Perform the necessary repair operation.
5. When the repair work is completed, return the ignition switch to the ″LOCK″ position before connecting
the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of all control units using CONSULT-III.
Service Notice or Precaution for EPS SystemINFOID:0000000001703871
CAUTION:
Check or confirm the following item when performing the trouble diagnosis.

PRECAUTIONS
STC-3
< SERVICE INFORMATION >[EPS]
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• Check any possible causes by interviewing the symptom and it’s condition from the customer if any
malfunction, such as EPS warning lamp turns ON, occurs.
• Check if air pressure and size of tires are proper, the specified part is used for the steering wheel,
and control unit is genuine part.
• Check if the connection of steering column assembly and steering gear assembly is proper (there is
not looseness of mounting bolts, damage of rods, boots or sealants, and leakage of grease, etc).
• Check if the wheel alignment is adjusted properly.
• Check if there is any damage or modification to suspension or body resulting in increased weight or
altered ground clearance.
• Check if installation conditions of each link and suspension are proper.
• Check if the battery voltage is proper
• Check connection conditions of each connector are proper.
• Before connecting or disconnecting the EPS control unit har-
ness connector, turn ignition switch “OFF” and disconnect
battery ground cable. Because battery voltage is applied to
EPS control unit even if ignition switch is turned “OFF”.
• When connecting or disconnecting pin connectors into or
from EPS control unit, take care not to damage pin terminals
(bend or break).
When connecting pin connectors, make sure that there are no
bends or breaks on EPS control unit pin terminal.
• Before replacing EPS control unit, perform EPS control unit
input/output signal inspection and make sure whether EPS
control unit functions properly or not. Refer to STC-9, "
EPS
Control Unit Input/Output Signal Reference Value".
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STC-4
< SERVICE INFORMATION >[EPS]
EPS SYSTEM
EPS SYSTEM
System DescriptionINFOID:0000000001703872
EPS CONTROL UNIT
• EPS control unit performs an arithmetical operation on data, such
as steering wheel turning force (sensor signal) from the torque
sensor, vehicle speed signal, etc. Then it generates an optimum
assist torque to the EPS motor according to the driving condition.
• EPS control unit decreases the output to EPS motor while
extremely using the power steering function (e.g., full steering) for
protecting EPS motor and EPS control unit (Protect overload sta-
tus). While activating protect overload status, the assist torque
gradually decreases, and the steering wheel turning force
becomes heavy. The normal assist torque reactivates by not steer-
ing.
• In case of an error in the electrical system, the fail-safe function
stops output signals to the EPS motor. Then the previous state is changed to the manual steering state.
• Self-diagnosis can be done with CONSULT-III.
EPS MOTOR
EPS motor provides the assist torque by control signal from EPS control unit.
TORQUE SENSOR
Torque sensor detects the steering torque, and transmit the signal to
EPS control unit.
REDUCTION GEAR
Reduction gear increases the assist torque provided from EPS motor with worm gears, and outputs to the col-
umn shaft.
EPS WARNING LAMP
Turns ON when there is a malfunction in EPS system. It indicates that fail-safe mode is engaged and enters a
manual steering state (Control turning force steering wheel becomes heavy).
Also turns ON when ignition switch is turned ON, for purpose of lamp check. Turns OFF after the engine starts
if system is normal.
EPS Warning Lamp Indication
SGIA1647E
SGIA1648E
Condition EPS warning lamp
Lamp checkTurns ON when ignition switch is turned ON.
Turns OFF after engine start.
EPS system malfunctionON
Other than above (system normal) OFF

EPS SYSTEM
STC-5
< SERVICE INFORMATION >[EPS]
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SchematicINFOID:0000000001703873
COMPONENTS FUNCTION DESCRIPTION
CAN CommunicationINFOID:0000000001703874
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-23, "
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 us-
ing 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

STC-6
< SERVICE INFORMATION >[EPS]
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
Fail-Safe FunctionINFOID:0000000001703875
• If any malfunction occurs in the system, and control unit detects the malfunction, EPS warning lamp on com-
bination 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 DiagnosisINFOID:0000000001703876
BASIC CONCEPT
• To perform trouble diagnosis, it is a must to have an 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 cus-
tomer.
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 inter-
view 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 without any symp-
tom 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 "How to Perform Trouble
Diagnosis" .
• Always erase memory after completing trouble diagnosis. Refer to STC-11, "
CONSULT-III Function (EPS)" .
• 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-3, "
General Precaution" .
INTERVIEW
• Complaints vary depending on the person. It is important to clarify
the customer's actual remarks.
• Ask the customer about what symptoms occur under what condi-
tions. Use the information to reproduce the symptom of confirm by
vehicle.
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