MDPS (TRW)

2 Application - Applied in both LHD and RHD as a standard including North American market. - TRW GEN2 (Model name) - Smaller and light motor applied - Higher torque capacity Introduction ItemMCHD Max. Current65A78A Diameter [D]Φ76mmΦ86.5mm Length [L]125mm55mm Weight2.6kg2kg Rated torque34N.m58N.m Motor typeD/CA/C ModelEngineGenM/EastEUAust.CANUSA TB F/L (05.6) ε-1.1OOO α -1.4OOO- α -1.6OOO- U-1.5SSS MC α -1.4SSS α -1.6SSS--- U-1.6SSS HD γ-1.6SSS--- β-2.0SSSSSS U-1.6SSS---

3 System structure Introduction Steering Column U/Joint MDPS SYSTEM MOBIS Power Head MOBIS LWR MTG BRKT Steering Gearbox COCKPIT MODULE CHASSIS MODULE MOBIS

4 Power head Components Worm Wheel O-Ring Bearing PCB Disk Light Guide Dust Cover Bearing Circle Lip Quill Shaft Assy Sensor deploy view ASSY section view Motor ECU Worm Gear Worm Wheel Bearing Spring ASSY exterior To columnTo U/Joint

5 Power head Components Main Housing Anti-Rattle Spring Worm Wheel Sensor Assy ECU MotorWorm Shaft Assy Bearing Oval Ring & Cover

6 Control logic System Control + Main input signals for the control logic Steering Wheel Torque Steering Wheel Position (Angle) Vehicle Speed Motor Command Active Return VSS Yaw Damping VSS Angle Assistance Boost Curve Angle Torque VSS Torque

7 Torque sensor principle System Control Angle & torque sensor Gear Box Motor Rack & Pinion Gear LA A LA B Motor position sensor Linear Array 128 pixel Narrow spoke disk wide spoke disk Index point

8 ASP (Absolute Steering Position) calibration System Control When ? - MDPS Assmbly was replaced with new one or used one from the other vehicles. - MDPS ECM (TBD) was replaced with new one or used one from the other vehicles. - After wheel alignment adjustment.

9 ASP (Absolute Steering Position) calibration System Control How? 1)Ignition key ON (engine off) and set the front tire and steering wheel on the center (neutral) position. - For lower steering effort, IG ON(engine run) IG off and on whithin 2 3 seconds. 2)Connect the scanner and Enter into the ASP calibration menu on the scanner.

10 ASP (Absolute Steering Position) calibration System Control How? 3) Rotate the steering wheel more than ±180°(Left and right) from the center position - To detect the location of index point. 4) Rotate the steering (left and right) wheel until the screen in the scanner becomes as below. That is, if the index point is detected, the next procedure will be followed automatically. Scanner will skip this procedure if the index point already detected !

11 ASP (Absolute Steering Position) calibration System Control How? 5) Set the front tire and steering wheel on the neutral position (±2°) and press enter key in the scanner.. 6) Press the esc key and move to the current data in order to confirm the calibration status. Detect or Not detect: Every IG off & on, this value will show detect or not detect depending on the steering wheel position. But it will get detect naturally as the steering wheel is rotated more than 180° while driving. (not detect does not mean the calibration fault.) CAL&INDEX: Calibration is OK and Index was found.

12 ASP (Absolute Steering Position) calibration System Control How? 7) Finally check the system rotating the steering wheel and also DTC must be checked. If you have following DTC after ASP calibration, it means that the steering wheel neutral position was excessively out of specification (step 1) and you have to try again from the first step. After DTC detection, the angle value will be fixed by zero. Angle Sensor Fault

13 ASP (Absolute Steering Position) calibration System Control What happen if it is not done? 1)In case of replacement with new part - Motor assist is available but warning lamp will blink and active return (on-center control) will stop. 2) In case of replacement with used part - Motor assist is available and warning lamp will not turn on. Active return (on-center control) will stop. What happen if it was done with wrong way? (improper steering wheel center position) - You may have DTC (C1259) without warning lamp on. However, the motor assist is available but the active return (on-center control) will stop.

14 Input & Output System Control SymbolDescriptionPin No.Reference VbattBattery(+)1 GNDBattery(-)2 CAN_BUSCAN High3CAN 2.0B, 500kbps CAN_BUSCAN Low6CAN 2.0B, 500kbps CAN_BUSCAN High7Not used CAN_BUSCAN Low4Not used IGNIgnition switch input5 NCSpare8Not used

15 Power supply & Relay System Control Motor relay (built in motor) ECM relay (built in ECM) - Every ignition off from engine running, the relay will sound (off) after 2 3 seconds. - However, if you turn the ignition on before 2 3 seconds, the motor assist is available under the ignition on condition even though the engine is not running.

16 Overheat Protection (Derating motor current ) System Control - Before the DTC(C1603) is detected (before the temperature reaches 85°), as soon as the steering torque reaches to maximum value, the motor current will decrease by 40% immediately in order to prevent the overheat in the system in advance.

17 Understanding of service data Diagnosis Compensation value - Stopped - Cranking - Running

18 Failsafe for vehicle speed signal fault Diagnosis - The vehicle speed signal comes from PG-B in A/T through PCM(or TCM) and CAN. - Warning lamp OFF, No DTC and Motor ON (Default vehicle speed is 40km/h) Normal conditionPG-B open circuit

19 Failsafe for IGN1 signal fault Diagnosis - IG1 signal is used to detect the engine status (not for the MDPS ECM system power) Failsafe for engine speed signal fault For example, disconnect the CKP sensor while driving and confirm the symptom. - Warning lamp ON (IG On condition), - No DTC - Motor assist ON for 30 seconds and turn off for the safety. ItemsWhile engine runningBefore engine start FailureIgnition signal open circuit Warning lampXO Motor Assist (while engine run) OX DTCC1103

20 Failsafe for CAN fault Diagnosis One or two CAN lines (High or Low) are open/short to ground circuit OR Both CAN lines (High & Low) are shorted circuit each other 1)Warning lamp turns on immediately. (while driving or IG on before engine starting) 2)Motor assists the steering under the ignition on condition. (engine running or not) 3)Motor assists the steering for about 1 minute under the ignition off condition. (Because cannot identify the engine is running or not) 4)Relevant DTC for CAN is stored. (C1611 CAN Timeout EMS) - Must clear DTC with scanner. (Not erased automatically even though the fault is disappeared) 5)Not possible to communicate with the scanner.

21 Warning lamp Diagnosis 1) Warning lamp ON + Motor stop: Critical fault - Torque sensor fault - Motor or Relay fault - MDPS ECM internal fault - IG signal fault (from next power cycle) 2) Warning lamp ON + Motor assist: Minor fault - CAN related faults 3) Warning lamp OFF + Motor assist: Minor fault - ASP calibration failure - Variant coding fault - Vehicle speed signal fault 4) Warning lamp OFF + Motor stop - Battery voltage high or low

22 Varient coding Diagnosis Default