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![NISSAN LATIO 2008 Service Repair Manual STC-6
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TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
Fail-Safe FunctionINFOID:0000000001703875
• If any malfunction occurs in the system, and control unit detects the malfunction, NISSAN LATIO 2008 Service Repair Manual 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,](/manual-img/5/57360/w960_57360-2688.png)
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.
SEF233G
SEF234G
SEF907L
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TROUBLE DIAGNOSIS
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Component Parts LocationINFOID:0000000001703877
SGIA1623E
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STC-8
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Wiring Diagram - EPS -
INFOID:0000000001703878
BGWA0001E
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TROUBLE DIAGNOSIS
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EPS Control Unit Input/Output Signal Reference ValueINFOID:0000000001703879
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.
BGWA0002E
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![NISSAN LATIO 2008 Service Repair Manual STC-10
< SERVICE INFORMATION >[EPS]
TROUBLE DIAGNOSIS
*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 t NISSAN LATIO 2008 Service Repair Manual STC-10
< SERVICE INFORMATION >[EPS]
TROUBLE DIAGNOSIS
*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 t](/manual-img/5/57360/w960_57360-2692.png)
STC-10
< SERVICE INFORMATION >[EPS]
TROUBLE DIAGNOSIS
*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.
EPS Terminal and Reference ValueINFOID:0000000001703880
EPS HARNESS CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUES FOR EPS CONTROL UNIT
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
SGIA1624E
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Data are reference values and are measured between each terminal and ground.
CAUTION:
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Data are reference values and are measured between each terminal and ground.
CAUTION:
When using a circuit tester](/manual-img/5/57360/w960_57360-2693.png)
TROUBLE DIAGNOSIS
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Data are reference values 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.
CONSULT-III Function (EPS)INFOID:0000000001703881
FUNCTION
CONSULT-III can display each diagnostic item using the diagnostic test modes shown following.
SELF-DIAG RESULTS MODE
Display Item List
Te r m i n a lWire
colorItem Condition Data (Approx.)
4 V Torque sensor sub Engine runningSteering wheel: Not steering
(There in 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
9 L CAN-H — —
10 O Power supplyIgnition switch: ON Battery voltage
Ignition switch: OFF 0 V
16 P CAN-L — —
17 R Power supply (Memory back-up)Ignition switch: ON Battery voltage
Ignition switch: OFF Battery voltage
18 B Ground Always 0 V
19 — Motor (+) — —
20 — Motor (–) — —
Diagnostic test mode Function Reference page
Self-diagnostic results • Self-diagnostic results can be read and erased quickly."SELF-DIAG
RESULTS
MODE"
Data monitor • Input/Output data in the EPS control unit can be read."DATA MONI-
TOR"
CAN diagnostic support monitor • The results of transmit/receive diagnosis of CAN communication can be read.LAN-6
ECU part number • EPS control unit part number can be read."EPS CON-
TROL UNIT
PART NUM-
BER"
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![NISSAN LATIO 2008 Service Repair Manual STC-12
< SERVICE INFORMATION >[EPS]
TROUBLE DIAGNOSIS
CAUTION:
If “CAN COMM CIRCUIT [U1000]” is displayed with other DTCs, first perform the trouble diagnosis for CAN communication
line.
How to Er NISSAN LATIO 2008 Service Repair Manual STC-12
< SERVICE INFORMATION >[EPS]
TROUBLE DIAGNOSIS
CAUTION:
If “CAN COMM CIRCUIT [U1000]” is displayed with other DTCs, first perform the trouble diagnosis for CAN communication
line.
How to Er](/manual-img/5/57360/w960_57360-2694.png)
STC-12
< SERVICE INFORMATION >[EPS]
TROUBLE DIAGNOSIS
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.
2. Turn ignition switch “OFF” to erase memory.
3. Turn ignition switch “ON” and select “SELF-DIAG RESULTS” mode with CONSULT-III.
4. Touch “ERASE” on CONSULT-III screen to erase DTC memory.
CAUTION:
If memory cannot be erased, perform diagnosis.
DATA MONITOR
Display Item List
EPS CONTROL UNIT PART NUMBER
Display a part number of EPS control unit carried by a vehicle.
Item
(CONSULT-III 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-14, "
DTC C1601
BATTERY VOLT"
TORQUE SENSOR
[C1604]When the torque sensor malfunction assembled in steering column
assembly is detected. STC-15, "DTC C1604
TORQUE SENSOR"
EPS MOTOR
[C1606]When the motor driver malfunction of EPS control unit or EPS motor
malfunction is detected.STC-16, "DTC C1606
EPS MOTOR"
EEPROM
[C1607]When the memory (EEPROM) system malfunction is detected in
EPS control unit.STC-17, "DTC C1607
EEPROM"
CONTROL UNIT
[C1608]When the internal malfunction is detected in EPS control unit.STC-17, "DTC C1608
CONTROL UNIT"
CAN VHCL SPEED
[C1609]When the malfunction is detected in vehicle speed signal received
with CAN communication.STC-18, "DTC C1609
CAN VHCL SPEED"
CAN ENG RPM
[C1610]When the malfunction is detected in engine status signal received
with CAN communication.STC-19, "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-19, "DTC U1000
CAN COMM CIRCUIT"
NO DTC IS DETECTED.
FURTHER TESTING MAY BE RE-
QUIRED.No NG item has been detected. —
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
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Symptom ChartINFOID:0000000001703882
If EPS warning lamp turns ON, perform self-diagnosis. Refer to STC-11, " NISSAN LATIO 2008 Service Repair Manual TROUBLE DIAGNOSIS
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Symptom ChartINFOID:0000000001703882
If EPS warning lamp turns ON, perform self-diagnosis. Refer to STC-11, "](/manual-img/5/57360/w960_57360-2695.png)
TROUBLE DIAGNOSIS
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Symptom ChartINFOID:0000000001703882
If EPS warning lamp turns ON, perform self-diagnosis. Refer to STC-11, "CONSULT-III Function (EPS)" .
Symptom Condition Check item Reference page
EPS warning lamp does not turn ON when ig-
nition switch to “ON”.
(EPS warning lamp check)Ignition switch: ONCAN communication line
STC-21
Combination meter
EPS warning lamp does not turn OFF for sev-
eral seconds after starting the engineEngine runningCAN communication line
STC-21
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-22
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-23
Steering 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-24
Steering wheel turning force
(Mechanical malfunction)