DETAILED FLOW
- COLLECT THE INFORMATION FROM THE CUSTOMER It is also important to clarify customer complaints before inspection. First of all, reproduce 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. GO TO 2.
- BASIC INSPECTION Check the power steering fluid leakage and the power steering fluid level. Refer to " «INSPECTION»(ref-388052-S19269934092011022800000) ". Check the drive belt tension. Refer to " «CHECKING DRIVE BELTS»(ref-388044-S15393606542011022800000) ". Check the power steering gear for damages, cracks and oil leakage. Refer to " «INSPECTION»(ref-388052-S19269934092011022800000) ". Check the relief oil pressure. Refer to " «INSPECTION»(ref-388052-S42266479212011022800000) ". GO TO 3.
- TROUBLE DIAGNOSIS FOR SYMPTOM Perform the diagnosis by symptom. Refer to " «DESCRIPTION»(ref-388075-S16228389472011022800000) ". GO TO 4.
- FINAL CHECK Check the input/output standard values for the power steering control unit. Are the power steering control unit input/output values within standard ranges respectively? YES >> Inspection End NO >> GO TO 2 .
Scheme 24
Scheme 24: CONTROL DIAGRAM
Scheme 25
Scheme 25: System Description
- The EPS system controls the power steering solenoid valve through the power steering control unit.
- The valve driving voltage to control the power steering solenoid valve varies according to the vehicle speed.
PHYSICAL VALUES
TERMINALS REFERENCE CHART Terminal No. Wire color Description Condition Value (Approx.) + - Signal name Input/Output 1 Ground R/Y Power steering solenoid valve voltage Output Vehicle speed: 0 km/h (0 MPH) (Engine is running) 4.4 - 6.6 V Vehicle speed: 100 km/h (62 MPH) 2.5 - 3.7 V 3 Ground G Ignition power supply Input Ignition switch: ON Battery voltage Ignition switch: OFF 0 V 5 Ground LG/W Power steering solenoid valve ground - Always 0 V 6 Ground B Ground - Always 0 V 8 Ground L/B Vehicle speed signal Input Vehicle speed: 40 km/h (25 MPH) CAUTION: Check air pressure of tire under standard condition. 10 Ground V/W Engine speed signal Input Engine speed: At idle (Warm-up condition) Engine speed: Approx. 2,000 RPM (Warm-up condition)
| CAUTION | When using circuit tester or oscilloscope to measure voltage for inspection, be sure not to extend forcibly any connector terminals. |
Scheme 26
- EPS system enters the fail-safe mode (that allows the steering force to be controlled without impairing the drive ability) if any of the input/output signals to/from EPS system (power steering control unit) deviate from the standard. NOTE: The system enters the fail-safe mode if the engine speed remains at 1,500 RPM or more for over 10 seconds while the vehicle is stopped. This is normal.
- The fail-safe function is cancelled when a vehicle speed signal of 2 km/h (1.2 MPH) or more is inputted or the key switch is turned OFF --> ON. EPS system restores the normal operation at that time. FAIL SAFE FUNCTION REFERENCE CHART Function Warning lamp DTC No. Detection point (malfunction part) Malfunction part and cause Fail-safe function - - Vehicle speed signal Engine speed is 1,500 RPM or more and there is no vehicle speed signal input for over 10 seconds during vehicle travel. Vehicle speed signal has abruptly dropped from 30 km/h (19 MPH) or more to 2 km/h (1.2 MPH) or less within 1.4 seconds.
Scheme 27
Scheme 27: Wiring Diagram
Scheme 28
Scheme 29
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT PRE-TENSIONER"
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 AIRBAG -- MAXIMA " and SEAT BELTS -- MAXIMA " articles.
| 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 AIRBAG . Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this Service Information. SRS wiring harnesses can be identified by yellow and/or orange harnesses or harness connectors. |
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
| WARNING | When working near the Airbag Diagnosis Sensor Unit or other Airbag System sensors with the Ignition ON or engine running, DO NOT use air or electric 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 3 minutes before performing any service. |
Scheme 30
- Disconnect negative battery terminal. Refer to " «REMOVAL AND INSTALLATION (BATTERY)»(ref-388040-S08852523192011022800000) ".
- Remove Audio/Navi unit. Refer to " «REMOVAL AND INSTALLATION»(ref-388076-S08096025092011022800000) " (base audio), " «REMOVAL AND INSTALLATION»(ref-388076-S40290873202011022800000) " (Bose w/ monochrome display), " «REMOVAL AND INSTALLATION»(ref-388076-S35974645152011022800000) " (Bose w/ color display), " «REMOVAL AND INSTALLATION»(ref-388076-S12949408612011022800000) " (Bose w/ color display w/Navi).
- Remove automatic drive position control unit, if equipped. Refer to " «REMOVAL AND INSTALLATION»(ref-388077-S39647720122011022800000) ".
- Remove EPS control unit (1) from the bracket.
- Disconnect EPS control unit connector (A) and remove the EPS control unit (1).
