Nissan Maxima Service and Repair Manual: Steering control system
- Basic inspection
- System description
- DTC/circuit diagnosis
- ECU diagnosis information
- Wiring diagram
- Symptom diagnosis
- Unit removal and installation
DIAGNOSIS AND REPAIR WORKFLOW Work Flow DETAILED FLOW 1.COLLECT THE INFORMATION FROM THE CUSTOMER It is also important to clarify customer complaints before inspection. First of all, reproduce symptoms, andunderstand them fully. Ask customer about his/her complaints carefully. In some cases, it will be necessary tocheck symptoms by driving vehicle with customer. 2.BASIC INSPECTION Check the power steering fluid leakage and the power steering fluid level. Refer to ST-12, "Inspection". Check the drive belt tension. Refer to EM-14, "Checking Drive Belts". Check the power steering gear for damages, cracks and oil leakage. Refer to ST-12, "Inspection". Check the relief oil pressure. 3.
EPS SYSTEM System Diagram CONTROL DIAGRAM System Description The EPS system controls the power steering solenoid valvethrough the power steering control unit. The valve driving voltage to control the power steering solenoid valve varies according to the vehicle speed. OPERATION PRINCIPLE During Parking (When Turning The Steering Wheel To The Right) Power steering solenoid valve is closed while a vehicle is stopped. Pinion "1R", "2R" and "3R" are closed depending on steering torque of steering wheel. Oil pressure "P" in the gear housing assembly is the sum of oil pressures occurring in "2R" and "3R". Thisresults in a light steering force because of high pressure.
POWER STEERING CONTROL UNIT Reference Value TERMINA LAYOUT PHYSICAL VALUES CAUTION: When using circuit tester or oscilloscope to measure voltage for inspection, be sure not to extend forcibly any connector terminals. Fail Saf EPS system EPS system enters the fail-safe mode (that allows the steering force to be controlled without impairing the drive ability) if any ofthe input/output signals to/from EPS system (power steering controlunit) deviate from the standard.NOTE:The system enters the fail-safe mode if the engine speed remainsat 1,500 RPM or more for over 10 seconds while the vehicle isstopped. This is normal. The fail-safe function is cancelled when a vehicle speed signal of 2 km/h (1.
ELECTRONICALLY CONTROLLED POWER STEERING SYSTEM Wiring Diagram
UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION) Description Hard steering when fully turning the steering wheel. Light steering when driving at a high speed. Diagnosis Procedure 1.CHECK SYSTEM FOR POWER SUPPLY AND GROUND Perform trouble diagnosis for power supply and ground circui 2.CHECK SYSTEM FOR VEHICLE SPEED SIGNAL Perform trouble diagnosis for vehicle speed si 3.CHECK SYSTEM FOR ENGINE SPEED SIGNAL Perform trouble diagnosis for engine speed signa 4.CHECK SYSTEM FOR POWER STEERING SOLENOID VALVE Perform trouble diagnosis for power steering solenoid valve.
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELTPRE-TENSIONER" The Supplemental Restraint System such as "AIR BAG" and "SEAT BELT PRE-TENSIONER", used alongwith a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certaintypes of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRSsystem uses the seat belt switches to determine the front air bag deployment, and may only deploy one frontair bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
EPS CONTROL UNIT Removal and Ins REMOVAL Disconnect negative battery terminal. Refer to PG-67, "Removal and Installation (Battery)". Remove audio display unit. Refer to AV-73, "Removal and Installation" (BASE AUDIO), AV-161, "Removaland Installation" (BOSE W/MONOCHROME DISPLAY), AV-481, "Removal and Installation" (BOSE W/COLOR DISPLAY), AV-652, "Removal and Installation" (BOSE W/COLOR DISPLAY W/NAVIGATION). Remove automatic drive position control unit (if equipped). Refer to ADP-170, "Removal and Installation". Remove EPS control unit (1) from the bracket. Disconnect EPS control unit harness connector (A) and remove the EPS control unit (1).