Variable Gear Ratio Steering (Diagnostic Codes & Symptom Tests): Overview Lexus LX J200

DESCRIPTION

If the steering control ECU or steering actuator is replaced, or if the tie-rod ends are adjusted, VGRS system calibration is required. If the steering control ECU detects that steering angle adjustment is incomplete, it will store DTC C1591/51.

The steering control ECU first checks the actuator angle neutral position calibration flag after entering test mode. If the ECU detects that steering actuator angle neutral position calibration is incomplete twice, it will store DTC C1592/52.

If the steering control ECU detects a steering actuator standard position error, it will store DTC C1593/53.

Signal transmission between the steering control ECU and steering angle sensor is performed via serial communication.

If an error occurs between them in serial communication, the ECU will store DTC C1595/55.

HINT

*: A tire angle of 36° and a motor rotation angle of 36° correspond to the steering wheel angle. The amount of change in tire angle and motor rotation angle is from when the mode is changed to test mode.

Scheme 14

Scheme 15

Scheme 16

1. CHECK DTC (CAN COMMUNICATION SYSTEM) Check for DTCs in the CAN communication system. Refer to «DIAGNOSIS SYSTEM». RESULT Result Proceed to DTC is not output A DTC is output B B --> See step 7 A: Go to next step
2. CHECK STEERING ANGLE SENSOR Check if a steering angle sensor that complies with the vehicle specifications is installed. OK A steering angle sensor that complies with the vehicle specification is installed. NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (STEERING CONTROL ECU - STEERING ANGLE SENSOR) Disconnect the E84 steering control ECU connector. Disconnect the E11 steering angle sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E84-10 (SS1-) - E11-7 (SS1-) Always Below 1 ohms E84-19 (SS1+) - E11-8 (SS1+) E84-19 (SS1+) - Body ground Always 10 kohms or higher E84-10 (SS1-) - Body ground E84-19 (SS1+) - E84-10 (SS1-) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK STEERING ANGLE SENSOR Disconnect the E84 steering control ECU connector. Move the shift lever to N. Jack up the vehicle. Check the waveform of the steering angle sensor using an oscilloscope. HINT: The voltage must be measured with the steering angle sensor connector connected. Standard Voltage Tester Connection Switch Condition Specified Condition E84-19 (SS1+) - E84-10 (SS1-) Engine switch on (IG), steering wheel rotated slowly Pulse generation (0 to 5 V) HINT: The output voltage should fluctuate up and down similarly to the diagram when the wheel is turned slowly. NG --> See step 6 OK --> See step 5
5. REPLACE STEERING CONTROL ECU. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/electronic-steering/#variable-gear-ratio-steering-service-information)
6. REPLACE STEERING ANGLE SENSOR. Refer to «REMOVAL»
7. GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING). Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»

The steering control ECU drives the actuator while the steering wheel is turned to set the gear ratio. It detects the current flowing into the actuator motor driving circuit.

If the steering control ECU detects excessive current, it will store DTC C15A1/61, turn on the master warning light, and stop VGRS operation.

Scheme 17

The steering control ECU drives the actuator based on steering angle sensor signals and vehicle speed signals.

If the steering control ECU detects excessive current flowing into the steering actuator, or an internal malfunction, it will turn on the master warning light, store DTC C15A2/62, and stop VGRS operation.

If the steering control ECU detects a malfunction in the motor drive circuit, it will turn the master warning light on, store DTC C15A6/62, and stop VGRS operation.

Scheme 18

The steering actuator drives the internal motor using the current output from the steering control ECU to change the relative angle between the tire angle and steering wheel angle.

The rotation angle sensor in the steering actuator detects the motor rotation angle and outputs this information to the steering control ECU.

If the steering control ECU detects a malfunction in the rotation angle sensor circuit, it will store DTC C15A3/63.

HINT

*: A tire angle of 36° and a motor rotation angle of 36° correspond to the steering wheel angle. The amount of change in tire angle and motor rotation angle is from when the mode is changed to test mode.

Scheme 19

Scheme 20

Scheme 21

1. CHECK HARNESS AND CONNECTOR (STEERING CONTROL ECU - STEERING ACTUATOR) Disconnect the E84 steering control ECU connector. Disconnect the E85 steering actuator connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E84-4 (S1) - E85-2 (S1+) Always Below 1 ohms E84-6 (RV) - E85-1 (RV+) E84-14 (S2) - E85-9 (S2+) E84-15 (RG) - E85-10 (RG+) E84-4 (S1) - E84-6 (RV) Always 10 kohms or higher E84-4 (S1) - E84-14 (S2) E84-4 (S1) - E84-15 (RG) E84-6 (RV) - E84-14 (S2) E84-6 (RV) - E84-15 (RG) E84-14 (S2) - E84-15 (RG) E84-4 (S1) - Body ground E84-6 (RV) - Body ground E84-14 (S2) - Body ground E84-15 (RG) - Body ground NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK STEERING ACTUATOR Disconnect the E84 steering control ECU connector. Measure the resistance according to the value(s) in the table below. HINT: The resistance must be measured with the steering actuator connector connected. Standard Resistance Tester Connection Condition Specified Condition E84-4 (S1) - E84-6 (RV) Always Below 200 ohms E84-4 (S1) - E84-14 (S2) E84-4 (S1) - E84-15 (RG) E84-6 (RV) - E84-14 (S2) E84-6 (RV) - E84-15 (RG) E84-14 (S2) - E84-15 (RG) E84-4 (S1) - Body ground Always 10 kohms or higher E84-6 (RV) - Body ground E84-14 (S2) - Body ground E84-15 (RG) - Body ground NG --> See step 3 OK --> See step 4
3. REPLACE STEERING ACTUATOR ASSEMBLY. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/electronic-steering/#variable-gear-ratio-steering-service-information__removal)
4. REPLACE STEERING CONTROL ECU. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/electronic-steering/#variable-gear-ratio-steering-service-information)

When the VGRS system is normal, the steering actuator conducts current from the steering control ECU to the steering actuator solenoid to release the lock mechanism, enabling motor operation.

The steering actuator does not operate under any of the following conditions

1. The engine switch is off.
2. The motor in the actuator is locked by the lock mechanism to prevent rotation (fail-safe function).
3. The system is being protected from overheating (fail-safe function).

If the steering control ECU detects a malfunction in the steering actuator lock mechanism or a motor rotation angle error, it will store these DTCs.

If the steering control ECU detects a malfunction in the lock mechanism, it will turn the master warning light on, store DTC C15A5/65, and stop VGRS operation.

Scheme 22

Scheme 23

Scheme 24

1. CHECK HARNESS AND CONNECTOR (STEERING CONTROL ECU - STEERING ACTUATOR) Disconnect the E84 steering control ECU connector. Disconnect the E85 steering actuator connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E84-3 (LV) - E85-7 (LV+) Always Below 1 ohms E84-12 (LG) - E85-16 (LG+) E84-3 (LV) - Body ground Always 10 kohms or higher E84-12 (LG) - Body ground Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition E84-3 (LV) - Body ground Engine switch on (IG) Below 1 V E84-12 (LG) - Body ground NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK STEERING ACTUATOR (STEERING CONTROL ECU - STEERING ACTUATOR) Disconnect the E84 steering control ECU connector. Reconnect the E85 steering actuator connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E84-3 (LV) - E84-12 (LG) Always 10 to 100 ohms E84-3 (LV) - Body ground Always 10 kohms or higher E84-12 (LG) - Body ground NG --> See step 3 OK --> See step 4
3. REPLACE STEERING ACTUATOR ASSEMBLY. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/electronic-steering/#variable-gear-ratio-steering-service-information__removal)
4. REPLACE STEERING CONTROL ECU. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/electronic-steering/#variable-gear-ratio-steering-service-information)

If the steering control ECU detects an internal malfunction, it will turn the master warning light on, store these DTCs, and stop VGRS operation.

If the steering control ECU detects an internal malfunction, it will turn the master warning light on, store DTC C15B4/71, and stop VGRS operation.

The steering control ECU detects a steering angle sensor malfunction by receiving an error signal from the steering angle sensor via CAN communication. If the steering control ECU detects this error signal, it will turn the master warning light on, store these DTCs, and stop VGRS operation.

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Scheme 29

1. CHECK DTC (CAN COMMUNICATION SYSTEM) Using the Techstream, check if the CAN communication system is functioning normally. Refer to «DIAGNOSIS SYSTEM». RESULT Result Proceed to DTC is not output A DTC is output B B --> See step 6 A: Go to next step
2. CHECK HARNESS AND CONNECTOR (STEERING CONTROL ECU +B1 TERMINAL VOLTAGE) Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition E82-10 (+B1) - Body ground Always 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK STEERING CONTROL ECU (+BO TERMINAL VOLTAGE) Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition E84-1 (+BO) - Body ground Always 11 to 14 V NG --> See step 7 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (STEERING ANGLE SENSOR) Disconnect the E11 steering angle sensor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition E11-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E11-2 (ESS) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK STEERING ANGLE SENSOR Disconnect the E11 steering angle sensor connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition E11-3 (BAT) - E11-2 (ESS) Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 8
6. GO TO CAN COMMUNICATION SYSTEM (DIAGNOSTIC TROUBLE CODE CHART). Refer to «DIAGNOSTIC TROUBLE CODE CHART»
7. REPLACE STEERING CONTROL ECU. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/electronic-steering/#variable-gear-ratio-steering-service-information)
8. REPLACE STEERING ANGLE SENSOR. Refer to «REMOVAL»

The steering control ECU detects a vehicle speed error by receiving an error signal from the skid control ECU via CAN communication.

If the steering control ECU detects this error signal, it will turn the master warning light on, store this DTC, and stop VGRS operation.

The steering control ECU monitors the IG power supply voltage.

If the steering control ECU detects a malfunction, it will turn on the master warning light, store DTC C15C6/77, and stop VGRS operation.

Scheme 30

The steering control ECU monitors PIG (motor power source voltage) and detects a malfunction in the power supply relay (located inside the steering control ECU).

If the steering control ECU detects a malfunction, it will turn on the master warning light, store these DTCs, and stop VGRS operation.

Scheme 31

The steering control ECU receives signals from the skid control ECU, ECM and steering angle sensor via CAN communication. When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system first.

If the steering control ECU detects that the VGRS system has a malfunction, warning information is transmitted to the combination meter via CAN communication.

The combination meter will turn the master warning light on based on this information.

Warning information is transmitted via the following route

1. Steering control ECU --> (CAN) --> Network gateway ECU --> (CAN) --> Combination meter

Connecting terminals TC and CG of the DLC3 makes the master warning light blink and outputs DTCs.

Scheme 32

See also:
• REMOVAL
• REMOVAL
• ADJUSTMENT
• INSPECTION