NISSAN LATIO 2009 Service Repair Manual

STC
N
O P
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 fo r Steering Wheel Rota-
tion After Battery Disconnect ............................... ......
2
Service Notice or Precau tion for EPS System ..........3
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/O utput 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

PRECAUTIONS
STC-3
< SERVICE INFORMATION >
[EPS] C
D E
F
H I
J
K L
M A
B STC
N
O
P
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 al l control units using CONSULT-III.
Service Notice or Precaution for EPS System INFOID:0000000004307286
CAUTION:
Check or confirm the following item wh en performing the trouble diagnosis.
• Check any possible causes by interviewing the symptom and it’s condition from the customer if any
malfunction, such as EPS warn ing 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 steer ing 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 alignmen t is adjusted properly.
• Check if there is any damage or modification to su spension 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 disconnect ing 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 igniti on switch is turned “OFF”.
• When connecting or disconnect ing 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 inspectio n and make sure whether EPS
control unit functions properly or not. Refer to STC-9, " EPS
Control Unit Input/Output Signal Reference Value " . SEF289H
SEF291H
SDIA1848E

SGIA1648E

STC
N
O P
Schematic
INFOID:0000000004307288
COMPONENTS FUNCTION DESCRIPTION
CAN Communication INFOID:0000000004307289
SYSTEM DESCRIPTION CAN (Controller Area Network) is a serial communication li ne 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-26, " CAN System Specification Chart " .

STC-6< SERVICE INFORMATION >
[EPS]
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
Fail-Safe Function INFOID:0000000004307290
• 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 steer ing state. (Control turning force steering wheel
becomes heavy.)
How to Perform Trouble Diagnosis INFOID:0000000004307291
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 app licable 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 sy mptoms occur under what condi-
tions. Use the information to reproduce the symptom of confirm by
vehicle. SEF233G
SEF234G
SEF907L

STC
N
O P
Component Parts Location
INFOID:0000000004307292

STC
N
O P
EPS Control Unit Input/Output Signal Reference Value INFOID:0000000004307294
SPECIFICATIONS WITH CONSULT-III 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. B