PRECAUTIONSSTC-3
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000009951730
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. Information necessary to service t he system safely is included in the SR and SB section of
this Service Manual.
WARNING:
• To avoid rendering the SRS inoper ative, 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 in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
• When working near the Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
• When using air or electric power tools or hammers , always switch the Ignition OFF, disconnect the
battery and wait at least three mi nutes before performing any service.
Service Notice and Precautions for Hydrau lic Pump Electric Power Steering System
INFOID:0000000009460340
• Check each tire for proper air pressure and size. Refer to WT-60, "Tire".
• Verify that the steering system components are G enuine NISSAN parts and have been installed properly.
• Check the steering column for loose mounting bolts.
• Check the steering gear assembly for loose mounting bolts. Check the inner sockets and outer sockets for
damage or wear. Inspect the boots and seals for leakage of power steering fluid.
• Verify proper wheel alignment. Refer to FSU-7, "Inspection and Adjustment"
.
• Check for any damage, wear, or modification to the suspension and body that would result in increased
weight or an improper wheelarch height. Refer to FSU-26, "Wheelarch Height (Unladen*
1)".
• Check for proper battery voltage.
• Verify that all power steering pump assembly connections are clean and fully seated.
• Verify that only Genuine NISSAN E-PSF is used. Use of any power steering fluid other than Genuine NIS-
SAN E-PSF will prevent the power st eering system from proper operation.
• An audible high pitch noise may be heard from the engine compartment when the steering wheel is oper-
ated, particularly at low speeds such as a parking lot maneuver. This condition is not a malfunction, rather
normal system operation. Steering at low speeds or parking lot maneuvers demands higher hydraulic assis-
tance, resulting in larger power st eering pump load and increased system noise.
• The power steering pump is electrically controlled by the power steering control module.
• Before connecting or disconnecting the power steeri ng control module harness connectors, turn ignition
switch “OFF” and disconnect battery ground cable. Batter y voltage is applied to power steering control mod-
ule even if ignition switch is turned “OFF”.
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STC-4
< SYSTEM DESCRIPTION >
COMPONENT PARTS
SYSTEM DESCRIPTION
COMPONENT PARTS
Component Parts LocationINFOID:0000000009460341
Component DescriptionINFOID:0000000009460342
1. Power steering oil pump assembly 2. Steering angle sensor(view with the steering wheel re-
moved) 3. ECM
4. Combination meter 5. EPS warning light
ALGIA0128ZZ
Component parts Reference
Power steering oil pump assembly STC-5, "Power Steering Oil Pump Assembly"
Steering angle sensorTransmits steering angle sensor signal to the power steering control module via CAN commu-
nication.
ECM Transmits engine speed signal to the power steering control module via CAN communication.
Combination meter Transmits vehicle speed signal to the power steering control module via CAN communication.
The combination meter also di splays the EPS warning light.
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SYSTEMSTC-7
< SYSTEM DESCRIPTION >
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When the steering angle speed is high or the vehicle speed is low,
force is generated by increasing discharge amount from the power
steering oil pump and by raising system hydraulic pressure.
OPERATION PRINCIPLE
When Steering Wheel is in the Neutral Position
Because the hydraulic routes open at the power steeri ng pump, gear housing right side, gear housing left side,
and reservoir tank, the hydraulic pressure applied to the right side and left side of the gear housing is equal
and no steering assist force is generated.
When Steering Wheel is Rotated to the Right
The hydraulic routes open from power steering pump to gear housing right side and from gear housing left
side to reservoir tank, providing left direction assist force to the rack.
JSGIA0916GB
JSGIA0918GB
JSGIA0919GB
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STC-8
< SYSTEM DESCRIPTION >
SYSTEM
When Steering Wheel is Rotated to the Left
The hydraulic routes open from power steering pump to gear housing left side and from gear housing right
side to reservoir tank, providing right direction assist force to the rack.
CONDITIONS FOR HYDRAULIC PUMP ELECTR IC POWER STEERING WARNING LAMP ON
• When the hydraulic pump electric power steering syst em is operating and steering assist force is being gen-
erated, the hydraulic pump electric power steering warning lamp is OFF.
• When the hydraulic pump electric power steering system is stopped by the fail-safe or protective function
and steering assist force is not being generated, the hy draulic pump electric power steering warning lamp
turns ON to inform the driver that t he system is in the manual steering state.
NOTE:
When the hydraulic pump electric power steering system warning lamp turns ON according to the protection
system, the cause is internal high temperature state of the hydraulic pump electric power steering system.
By stopping the engine, internal temperature of the s ystem decreases. After starting the engine, the system
returns to the normal state and the hydraulic pump elec tric power steering system warning lamp turns OFF.
(The system is not malfunctioning.) For informat ion about the protective function, refer to STC-9, "HYDRAU-
LIC PUMP ELECTRIC POWER STEERING SYSTEM : Protection Function".
• When the ignition switch is turned ON, this lamp turn s ON for lamp check (system check). When the system
is operating normally, the lamp turns OFF after the engine starts.
HYDRAULIC PUMP ELECTRIC POWE R STEERING SYSTEM : Fail-safeINFOID:0000000009460345
When an error occurs in the hydraulic pump electric pow er steering system, fail-safe brings the system to a
halt (manual steering) or restricted (constant steering assi st level) state. When the system is in a halt state,
fail-safe turns ON the hydraulic pump electric power steer ing warning lamp to warn the driver that the hydrau-
lic pump electric power steering system is in the manual steering state.
JSGIA0917GB
Condition Hydraulic pump electric power steering warning lamp
Ignition switch ON. (Lamp check) ON
After engine start (steering assist force is generated) OFF
When steering assist is stopped ON
DTC Fail-safe condition
C1143 Certain steering assist force
C1601 Manual steering state
C1606 Manual steering state
C1607 Certain steering assist force
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SYSTEMSTC-9
< SYSTEM DESCRIPTION >
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HYDRAULIC PUMP ELECTRIC POWER STEE RING SYSTEM : Protection Function
INFOID:0000000009460346
• When the steering wheel is operated repeatedly or turned all the way for a long period during parking or low
speed driving, the function of the hydraulic pump elec tric power steering system becomes limited to prevent
the system from overheating. Cont inued operation of the steering wheel will cause the hydraulic pump elec-
tric power steering system to stop and the hydraulic pum p electric power steering system warning lamp may
come ON. In this case, the steering wheel operation temporarily becomes hard. This is not a malfunction.
When the engine is turned OFF (ignition switch OFF) and steering operation is stopped for a while, the tem-
perature of the hydraulic pump electric power steer ing system decreases and the steering operation returns
to normal after restarting the engine.
• Then, the hydraulic pump electric power steering syste m warning lamp turns OFF. If the system is OFF
under the protection state, the hydraulic pump electr ic power steering system warning lamp turns ON to
warn that the system is in the manual steering state. (This is not a system malfunction.) In addition, the fol-
lowing DTC remains to distinguish from malfunction.
C1608 Manual steering state
U1000 Normal control
NOTE:
If the cause is in a different ECU, the state changes to fixed steering assist force.
DTC Fail-safe condition
DTC vehicle condition
C160A The system temporarily enters the manual steering state. (This is not a hydraulic pump electric
power steering system malfunction.)
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POWER STEERING CONTROL MODULESTC-11
< ECU DIAGNOSIS INFORMATION >
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ECU DIAGNOSIS INFORMATION
POWER STEERING CONTROL MODULE
Reference ValueINFOID:0000000009460348
VALUES ON THE DIAGNOSIS TOOL
*1: The value changes according to load of power steering motor.
*2: This is in close agreement with a motor speed command value. Although a quick steering operation may
cause disagreement, this is not a malfunction.
*3: Usually, 100% is displayed. An excessive steer ing operation gradually lowers the percentage. When left
standing, the percentage returns to 100%.
Monitor item Data monitor
Condition Display value
BATTERY VOLT Engine running Battery voltage (V)
STEERING ANGLE The steering wheel is not steered. Approx. 0.0 deg
The steering wheel is steered. Displays steering angle (deg)
STR ANG SPD The steering wheel is not steered. Approx. 0.0 deg/s
The steering wheel is steered. Displays steering angle speed (deg/s)
MOTOR CURRENT Engine running Steering wheel: Not steering (There is
no steering force) MAX approx. 10 A
*1
Steering wheel: Right or left turnDisplays consumption current of pow-
er steering control module (A)
MTR REV SPD COMM Engine running Steering wheel: Not steering (There is
no steering force) Shows an almost constant value
(rpm)
Steering wheel: Right or left turn The value changes as a steering
speed (rpm)
MTR REV SPD Engine running Steering wheel: Not steering (There is
no steering force) Shows an almost constant value
(rpm)
*2
Steering wheel: Right or left turn The value changes as a steering
speed (rpm)*2
C/U TEMP Engine running Displays temperature of inside of
power steering control module ( °C or
° F)
C/U TEMP A Engine running Displays temperature of inside of
power steering control module ( °C or
° F)
MTR ASSIST Engine running 100%
*3
ESTM VHCL SPDVehicle stopped 0.00 km/h or mph
While driving Approximately equal to the indication
on speedometer*4
(inside of ±10%)
WARNING LAMP Hydraulic pump electric power steering warning lamp: ON On
Hydraulic pump electric power steering warning lamp: OFF Off
ENGINE STATUS Engine not running STOP
Engine running RUN
Engine cranking CRANK
VHCL SPD JUDGE Vehicle speed signal can be received via CAN communication OK
Vehicle speed signal cannot be received via CAN communica-
tion NG
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STC-12
< ECU DIAGNOSIS INFORMATION >
POWER STEERING CONTROL MODULE
*4: This may not agree with the speedometer indication immediately after the ignition switch is turned ON. This
is not a malfunction.
TERMINAL LAYOUT
PHYSICAL VALUES
Fail-safeINFOID:0000000009460349
When an error occurs in the hydraulic pump electric pow er steering system, fail-safe brings the system to a
halt (manual steering) or restricted (constant steering assi st level) state. When the system is in a halt state,
fail-safe turns ON the hydraulic pump electric power steer ing warning lamp to warn the driver that the hydrau-
lic pump electric power steering system is in the manual steering state.
Protection FunctionINFOID:0000000009460350
• When the steering wheel is operated repeatedly or turned all the way for a long period during parking or low
speed driving, the function of the hydraulic pump elec tric power steering system becomes limited to prevent
the system from overheating. If the steering wheel is operated further more, the hydraulic pump electric
power steering system stops and the hydraulic pump el ectric power steering system warning lamp may be
turned ON. In this case, the steering wheel operation temporarily becomes hard. This is not a malfunction.
When the engine is turned OFF (ignition switch OFF) and steering operation is stopped for a while, the tem-
perature of the hydraulic pump electric power steeri ng system decreases and the steering operation returns
to normal after restarting the engine.
JSGIA0835ZZ
Te r m i n a l N o .
(Wire Color) Description
Condition Value
+ − Signal name Input/Output
1
(W) Ground Battery power supply Input Always Battery Voltage
2
(B) Ground Ground — Always 0 V
5
(BR) Ground Ignition power supply Input Ignition switch: ON Battery Voltage
Ignition switch: OFF 0 V
7
(P) — CAN-L Input/Output — —
8
(L) — CAN-H Input/Output — —
DTC Fail-safe condition
C1143 Certain steering assist force
C1601 Manual steering state
C1606 Manual steering state
C1607 Certain steering assist force
C1608 Manual steering state
U1000 Normal control
NOTE:
If the cause is in a different ECU, the state changes to fixed steering assist force.
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STC-20
< BASIC INSPECTION >
DIAGNOSIS AND REPAIR WORK FLOW
YES >> GO TO 6.
NO >> Check harness and connectors based on the information obtained by interview.
6.REPAIR OR REPLACE THE MALFUNCTIONING COMPONENTS.
• Repair or replace the malfunctioning components.
• Reconnect part or connector after repairing or replacing.
• When DTC is detected, erase self-diagnostic results for “EPS”.
>> GO TO 8.
7.IDENTIFY THE MALFUNCTIONING SYSTEM BY SYMPTOM DIAGNOSIS
Estimate the malfunctioning system based on symptom diagnosis and perform inspection.
Can the malfunctioning system be identified?
YES >> GO TO 8.
NO >> Check harness and connectors based on the information obtained by interview.
8.FINAL CHECK
With CONSULT
1. Check the reference value for power steering control module.
2. Recheck the symptom and check that sympto m is not reproduced on the same conditions.
Is the symptom reproduced?
YES >> GO TO 3.
NO >> Inspection End.
Diagnostic Work SheetINFOID:0000000009460355
Description
• In general, customers have their own criteria for a pr oblem. Therefore, it is important to understand the
symptom and status well enough by asking the customer about his/her concerns carefully. To systemize all
the information for the diagnosis, prepare the interview sheet referring to the interview points.
• In some cases, multiple conditions that appear simultaneously may cause a DTC to be detected.
Interview sheet sample
Interview sheet
Customer
name MR/MSRegistration
number Initial year
registration
Vehicle type VIN
Storage date Engine Mileage km (Mile)
Symptom †
The steering wheel position (center) is in the wrong position.
† Warning lamp turns on.
† Noise †Vibration
† Others
( )
First occurrence †Recently †Others ( )
Frequency of occurrence †Always †Under a certain conditions of †Sometimes (time(s)/day)
Climate con-
ditions †
Irrelevant
Weather †Fine †Cloud †Rain †Snow †Others ( )
Temperature †Hot †Warm †Cool †Cold †Temperature [Approx. °C ( °F)]
Relative humidity †High †Moderate †Low
Road conditions †
Urban area †Suburb area †High way
† Mountain road (uphill or down hill) †Rough road
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