Variable Gear Ratio Steering System (Diagnostics - Introduction): Other Lexus IS III

PRECAUTION [04/2013 - ]

1. PRECAUTION FOR DISCONNECTING CABLE FROM NEGATIVE BATTERY TERMINAL NOTE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected. System Name See Procedure Variable Gear Ratio Steering System Refer to «INITIALIZATION [04/2013 - ]»(ref-665529-S01115916402014102400000) Air Conditioning System
2. TROUBLESHOOTING PRECAUTIONS If a problem is caused by a poor connection of a terminal or poor installation of a part, reconnecting the terminal or removing and reinstalling the part may solve the problem or may temporarily return the system to normal. To determine the cause of a problem, check for DTCs or confirm the vehicle operating conditions when the problem occurred and note them down before disconnecting connectors or removing parts. Be sure to check for DTCs in other systems as a problem may be caused by a malfunction in another system. Other systems may store DTCs when the VGRS system is inspected. Therefore, check and clear any DTCs from other systems after inspecting the VGRS system. When the engine switch is turned on (IG)/off, the system start-up/stop operation is performed. At this time, a small operating sound can be heard and the steering wheel turns slightly. If "Fixed Val" is not displayed for "Direct Advance Wheel Angle Status" in the Data List, the VGRS system does not operate. If the steering wheel is turned left and right with the engine switch off, a noise can be heard. However, this is not a malfunction.
3. HANDLING AND OPERATING PRECAUTIONS Removal and installation of the VGRS ECU (front steering control ECU), steering actuator assembly and each sensor must be performed with the engine switch off unless specified. If the VGRS ECU (front steering control ECU), steering actuator assembly or a sensor is removed and installed, perform the test mode inspection, check for DTCs, and confirm that the normal system code is output. Other systems may store DTCs when the engine switch is turned on (IG) with the connector of the VGRS ECU (front steering control ECU) disconnected. Therefore, after performing repairs, check and clear DTCs for other systems.
4. PRECAUTIONS FOR REPLACEMENT OF STEERING SYSTEM PARTS If the VGRS ECU (front steering control ECU) or steering actuator assembly is replaced, perform actuator angle neutral point calibration and initialization. The VGRS ECU (front steering control ECU) cannot be disassembled or repaired. If there is any problem with the VGRS ECU (front steering control ECU), replace it with a new one.
5. PRECAUTIONS FOR STEERING WHEEL OFF-CENTER NOTE: If the steering wheel is still off-center after completing steering sensor initialization. Refer to «INITIALIZATION [04/2013 - ]»(ref-665552-S41026054322014102400000) , perform VGRS system calibration. Refer to «CALIBRATION [04/2013 - ]»(ref-665552-S22722382032014102400000) . HINT: The steering wheel may become off-center under any of the following conditions. These conditions do not indicate a malfunction. The steering wheel is turned when the engine switch is off. The steering wheel is turned quickly. The steering wheel is turned from lock to lock. If the steering wheel is off-center, drive the vehicle at 40 km/h (25 mph) or more for 5 seconds, or turn the steering wheel to the left and right with the vehicle stopped or while driving at low speeds. This may center the steering wheel. If one of the situations under Conditions Under Which VGRS System does Not Operate occurs, the steering wheel may temporarily become off-centered.
6. CONDITIONS UNDER WHICH VGRS SYSTEM DOES NOT OPERATE The VGRS system does not operate under any of the following conditions: The power supply voltage is low or too high. A fail-safe function is operating to protect the system from overheating. System control is suspended to prevent the motor in the steering actuator assembly and the VGRS ECU (front steering control ECU) from overheating. If the temperatures of the motor and ECU drop, the system returns to normal. Steering sensor zero point calibration has not been performed.

Scheme 6

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Scheme 8

CAUTION / NOTICE / HINT

HINT

1. Use the following procedures to troubleshoot the VGRS system.
2. *: Use the Techstream.

PROCEDURE

1. VEHICLE BROUGHT TO WORKSHOP Result Proceed to NEXT Result: 1 NEXT See step 2
2. INSPECT BATTERY VOLTAGE Standard Voltage 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding. Result Proceed to NEXT Result: 1 NEXT See step 3
3. CHECK CAN COMMUNICATION SYSTEM* Use the Techstream to check if the CAN communication system is functioning normally. Refer to «DIAGNOSIS SYSTEM [04/2013 - ]»(ref-665810-S14264089842014102400000) Result Result Proceed to CAN DTCs are not output. A CAN DTCs are output. B Result: 2 B GO TO CAN COMMUNICATION SYSTEM. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING [04/2013 - ]»(ref-665785-S15342612202014102400000) Result: 1 A See step 4
4. CHECK FOR DTCs* Check for DTCs. Refer to «DTC CHECK/CLEAR [04/2013 - ]»(ref-665552-S41604125052014102400000) Chassis > VGRS > Trouble Codes Clear the DTCs. Refer to «DTC CHECK/CLEAR [04/2013 - ]»(ref-665552-S41604125052014102400000) Chassis > VGRS > Clear DTCs Recheck for DTCs. Refer to «DTC CHECK/CLEAR [04/2013 - ]»(ref-665552-S41604125052014102400000) Chassis > VGRS > Trouble Codes Simulate the malfunction and check if the DTCs are output again. Refer to «DTC CHECK/CLEAR [04/2013 - ]»(ref-665552-S41604125052014102400000) Result Result Proceed to DTCs are not output. A DTCs are output. B DTCs are not output, and the malfunction cannot be simulated or checked C Result: 2 B See step 9 Result: 3 C SYMPTOM SIMULATION Result: 1 A See step 5
5. DTC TABLE Result Proceed to NEXT Result: 1 NEXT See step 6
6. CIRCUIT INSPECTION Result Proceed to NEXT Result: 1 NEXT See step 7
7. REPAIR Result Proceed to NEXT Result: 1 NEXT See step 8
8. CONFIRMATION TEST Result Proceed to NEXT Result: 1 NEXT END
9. PROBLEM SYMPTOMS TABLE Result Proceed to NEXT Result: 1 NEXT See step 10
10. CIRCUIT INSPECTION Result Proceed to NEXT Result: 1 NEXT See step 11
11. CONFIRMATION TEST Result Proceed to NEXT Result: 1 NEXT END

INITIALIZATION [04/2013 - ]

1. STEERING SENSOR INITIALIZATION HINT: If the cable is disconnected from the negative (-) battery terminal or the steering sensor connector is disconnected, the steering sensor zero point may be cleared. Even when the steering sensor zero point calibration has not been performed, the master warning light does not illuminate. Start the engine. Slowly turn the steering wheel 360° clockwise and counterclockwise twice or three times. Drive the vehicle on a straight road at 40 km/h (25 mph) or more for 5 seconds or more.

FREEZE FRAME DATA [04/2013 - ]

HINT

The VGRS system stores data when a trouble code is stored which can be viewed using the Techstream.

1. FREEZE FRAME DATA OF VGRS ECU (FRONT STEERING CONTROL ECU) Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Chassis / VGRS / Trouble Codes. Chassis > VGRS > Trouble Codes According to the display on the Techstream, select the trouble code data display with Freeze Frame Data. Chassis > VGRS Tester Display Measurement Item Range Normal Condition Steering Angle Steering angle Min.: -1638.40 deg Max.: 1638.35 deg -600 to 600 deg Steering Angle Changing Speed Steering angle changing speed Min.: -1638.40 deg/s Max.: 1638.35 deg/s -1146 to 1146 deg/s Vehicle Speed Vehicle speed Min.: 0.00 km/h (0 mph) Max.: 327.67 km/h (203 mph) Actual vehicle speed Starting Status Starting status Stop or Starting-up Engine stopped: Stop Engine running: Starting-up IG Power Supply Voltage IG power supply voltage Min.: 0.00 V Max.: 255.99 V 11 to 14 V PIG Power Supply Voltage PIG power supply voltage Min.: 0.00 V Max.: 255.99 V 11 to 14 V Power Supply Status Power supply status Normal, N Pos Stop, Cur Pos Stop or Prompt Stop Normal Limit Power Request (from EPS) Limit power request ON or OFF OFF Stop Request (from EPS) Stop request ON or OFF OFF System Heavily-loaded Status System heavily-loaded status ON or OFF OFF ECU Substrate Temperature ECU substrate temperature Min.: -256.00°C (-428°F) Max.: 255.99°C (492°F) Within 20°C (68°F) of ambient temperature Motor Temperature (ECU Calculated Value) Motor temperature Min.: -256.00°C (-428°F) Max.: 255.99°C (492°F) Within 20°C (68°F) of ambient temperature Ambient Temperature Ambient temperature Min.: -40°C (-40°F) Max.: 50°C (122°F) Same as ambient temperature System Overheat Status System overheat status Normal, Overheat-Weak, Overheat-Mid or Overheat-Strong Normal ECU Substrate Temperature (ECU Calculated Value) ECU substrate temperature Min.: -256.00°C (-428°F) Max.: 255.99°C (492°F) -40 to 70°C (-40 to 158°F) Wheel Angle (SIL Communication) Wheel angle (SIL communication) Min.: -1638.40 deg Max.: 1638.35 deg -600 to 600 deg Wheel Angle (CAN Communication) Wheel angle (CAN communication) Min.: -1638.40 deg Max.: 1638.35 deg -600 to 600 deg Steering Angle Sensor Communication Protocol Steering sensor communication protocol Calc Val Fix, SIL or CAN SIL Direct Advance Wheel Angle Direct advance wheel angle Min.: -1638.40 deg Max.: 1638.35 deg -10.5 to 10.5 deg Direct Advance Wheel Angle Status Direct advance wheel angle status Delete, Temp Val or Fixed Val Fixed Val Motor Resolver Electrical Angle Motor resolver electrical angle Min.: 0.00 deg Max.: 359.99 deg 0.00 to 359.99 deg Changing Amount of Motor Resolver Electrical Angle Changing amount of motor resolver electrical angle Min.: -180.00 deg Max.: 179.99 deg -46 to 46 deg Motor Resolver SIN Phase Shaped Width Motor resolver SIN phase amplitude/ Min.: -5.00 V Max.: 4.99 V -4.1 to 4.1 V Motor Resolver SIN Phase Offset Motor resolver SIN phase offset Min.: 0.00 V Max.: 19.99 V 5 to 15 V Motor Resolver COS Phase Shaped Width Motor resolver COS phase amplitude Min.: -5.00 V Max.: 4.99 V -4.1 to 4.1 V Motor Resolver COS Phase Offset Motor resolver COS phase offset Min.: 0.00 V Max.: 19.99 V 5 to 15 V Motor Resolver Shaped Width Squared Sum Sum of squares of motor resolver amplitudes Min.: 0.00 V^2 Max.: 25.00 V^2 1.4 to 16.6 V^2 Deep Groove Electrical Angle Position Deep groove electrical angle position Min.: 0.00 deg Max.: 359.99 deg 75 to 145 deg Neutral Position Calibration Status Neutral position calibration status Incmpl or Cmpl Cmpl Actuator Target Angle Actuator target angle Min.: -512.00 deg Max.: 511.98 deg -150 to 150 deg Actuator Angle Actuator angle Min.: -512.00 deg Max.: 511.98 deg -150 to 150 deg Pinion Angle Status Pinion angle status Invalid or Valid Valid Pinion Angle Pinion angle Min.: -2048.00 deg Max.: 2047.93 deg -600 to 600 deg Motor U Phase Voltage Motor U phase voltage Min.: 0.00 V Max.: 255.99 V 0 to 14 V Motor V Phase Voltage Motor V phase voltage Min.: 0.00 V Max.: 255.99 V 0 to 14 V Motor W Phase Voltage Motor W phase voltage Min.: 0.00 V Max.: 255.99 V 0 to 14 V Motor U Phase Current Motor U phase current Min.: -256.00 A Max.: 255.99 A -75 to 75 A Motor V Phase Current Motor V phase current Min.: -256.00 A Max.: 255.99 A -75 to 75 A Motor W Phase Current Motor W phase current Min.: -256.00 A Max.: 255.99 A -75 to 75 A Motor U Phase Duty Motor U phase duty Min.: 0.00% Max.: 100.00% 6 to 94% Motor V Phase Duty Motor V phase duty Min.: 0.00% Max.: 100.00% 6 to 94% Motor W Phase Duty Motor W phase duty Min.: 0.00% Max.: 100.00% 6 to 94% PIG Current PIG current Min.: -256.00 A Max.: 255.99 A -50 to 50 A Motor q Axis Target Voltage Motor q axis target voltage Min.: -32.00 V Max.: 31.99 V -6 to 6 V Motor q Axis Current Motor q axis current Min.: -256.00 A Max.: 255.99 A -92 to 92 A Motor d Axis Current Motor d axis current Min.: -256.00 A Max.: 255.99 A -10 to 13 A Motor Rotation Speed Motor rotation speed Min.: -32768 deg/s Max.: 32767 deg/s -17190 to 17190 deg/s Lock Solenoid Voltage Lock solenoid voltage Min.: 0.00 V Max.: 255.99 V 0 to 14 V Lock Status Lock status Pin Pos Indef, Pin Inserting, Pin Vadum Insert, Pin Inserted, Pin Insert Confirming, Pin Insert Confirmed, Pin Insert Mal, Release Start, Pin Release Confirmed, Pin Release Confirmed, Pin Release Mal, Pin Released, Pin Release Impos, Line Power OFF or Pin Insert Waiting Pin Released Lock Solenoid Duty Lock solenoid duty Min.: 0% Max.: 100% 0 to 100%

FAIL-SAFE TABLE [04/2013 - ]

1. FAIL-SAFE FUNCTION The VGRS ECU (front steering control ECU) performs fail-safe control according to the chart below when a malfunction occurs in the VGRS system. VGRS SYSTEM DTC Code Detection Condition Fail-safe Operation C1591/51 Actuator Neutral Position Calibration Undone Control is not started C1592/52 Actuator Neutral Position Calibration Incomplete Control is not started C1593/53 Actuator Standard Position Control is not started C1595/55 Lost Communication with Steering Angle Sensor Module (SIL) Returns the relative angle to the neutral position and stops or stops at the current position C15A1/61 Short in Motor Circuit Control is not started or stops C15A2/62 Open in Motor Circuit Control is not started or stops C15A3/63 Motor Rotation Angle Not Detected Control is not started C15A4/64 Motor Rotation Angle Malfunction Control is not stopped C15A5/65 Lock Mechanism Circuit Control is not started or stops C15A6/62 Actuator Motor Power Distribution Malfunction Control is not started or stops C15A9/66 Lock Holder Deviation Detection Control is not started or stops C15AA/66 Lock Mechanism Release Incomplete Control is not stopped C15AB/66 Lock Mechanism Insertion Control is not started or stops C15B1/71 ECU Malfunction (CPU) Control is not started or stops C15B2/72 ECU Malfunction (Internal Line) Control is not started or stops C15B3/73 ECU Malfunction (Substrate Temperature Sensor) Control continues C15B4/71 ECU Malfunction (Actuator Angle Record) Control is not started or stops C15B5/82 ECU Malfunction (Flash Memory) Control is not started or stops C15B6/83 ECU Malfunction (EEPROM) Control is not started or stops C15C1/74 Steering Angle Sensor Control is not started or stops C15C2/74 Steering Angle Sensor B+ Returns the relative angle to the neutral position and stops C15C3/75 Brake System Control Module Returns the relative angle to the neutral position and stops C15C4/68 Steering Signal Not Detected - C15C5/69 Motor Rotation Signal Not Detected - C15C6/77 IG Power Supply Voltage Returns the relative angle to the neutral position and stops C15C7/78 DC Motor Power Source Voltage Control is not started or stops C15C8/79 Power Supply Relay Failure Control is not started C15CA/79 EPS System Malfunction Returns the relative angle to the neutral position and stops C15CB/84 VSC System Malfunction Returns the relative angle to the neutral position and stops U0100/56 Lost Communication with ECM/PCM "A" Control is not started U0101/56 Lost Communication with TCM Returns the relative angle to the neutral position and stops U0125/56 Lost Communication with Yaw Rate Sensor Module Control continues U0126/56 Lost Communication with Steering Angle Sensor Module Returns the relative angle to the neutral position and stops U0129/56 Lost Communication with Brake System Control Module Returns the relative angle to the neutral position and stops U0131/56 Lost Communication with Power Steering Control Module Returns the relative angle to the neutral position and stops