Steering Lock (Diagnostic Codes & Circuit Tests): Overview Lexus ES XV40 facelift

DESCRIPTION

If the steering lock ECU determines that there is a malfunction inside the ECU, it outputs this DTC. The steering lock ECU diagnosis information cannot be read directly from the steering lock ECU by the tester. The diagnosis information from the steering lock ECU is transmitted to the tester via the certification ECU to the tester using the controller area network (CAN).

The main body ECU (*) controls the power supply to activate the steering lock motor. This prevents the steering from being locked while the vehicle is moving.

HINT

*: The power source control ECU is not a physical part. This code refers to the power source control function performed by the main body ECU.

Scheme 71

Scheme 72

Scheme 73

Scheme 74

1. INSPECT STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU) Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition E78-3 (IGE) - E78-1 (GND) The specified condition should be checked after performing the following: Turn the engine switch off Turn the engine switch on (ACC or IG) Motor activated: Below 1 V Motor not activated: 10 to 12 V E78-3 (IGE) - E78-1 (GND) The specified condition should be checked after performing the following: Move the shift lever to the P position Turn the engine switch off Open the driver's door Motor activated: Below 1 V Motor not activated: 10 to 12 V HINT: The steering lock ECU and steering lock actuator assembly are supplied as a unit. OK --> REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU) NG: Go to next step
2. CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BODY GROUND) Disconnect the E78 connector from the steering lock actuator assembly. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E78-1 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - MAIN BODY ECU) Disconnect the E61 connector from the main body ECU. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E78-3 (IGE) - E61-19 (SLR+) Always Below 1 ohms E78-3 (IGE) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE MAIN BODY ECU

The steering lock ECU receives power from the IG2 relay. When the digital signal from the certification ECU and the voltage from the IG2 relay are received by the steering lock ECU, the steering will be unlocked. The steering lock ECU will not lock the steering when power from the IG2 relay is present (this prevents the steering from being locked while the vehicle is moving).

Scheme 75

Scheme 76

Scheme 77

Scheme 78

1. INSPECT IGNITION RELAY NO. 2 Remove the IG2 relay from the engine room R/B. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition 3 - 5 Always 10 kohms or higher 3 - 5 When battery voltage is applied to terminals 1 and 2 Below 1 ohms NG --> REPLACE IGNITION RELAY NO. 2 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BODY GROUND) Disconnect the E78 connector from the steering lock actuator assembly. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E78-1 (GND) - Body ground Always Below 1 ohms E78-2 (SGND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BATTERY) Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition E78-6 (IG2) - E78-1 (GND) Engine switch on (IG) 10 to 14 V E78-6 (IG2) - E78-2 (SGND) Engine switch on (IG) 10 to 14 V Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition *E78-6 (IG2) - E78-7 (B) Engine switch off 10 kohms or higher *: This measurement is performed with the engine switch off to check for a short between IG2 and battery voltage. OK --> REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BATTERY)

The steering lock ECU is connected to the main body ECU and certification ECU. The steering lock ECU cannot activate the motor unless it receives permission signals from both ECUs. (The main body ECU permits the steering lock ECU to supply power to activate the motor.)

The unlock position sensor is one of the components in the steering lock actuator. The sensor switch contact closes when the steering lock is released. The steering lock release signal is then sent to the main body ECU. Receiving the signal, the ECU permits engine start. (This prevents the engine from being started with the steering locked.)

Scheme 79

Scheme 80

Scheme 81

1. INSPECT STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU) Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition E78-4 (SLP1) - E78-2 (SGND) Engine switch off Engine switch on (ACC or IG) Below 1 V OK --> CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START FUNCTION NG: Go to next step
2. CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - MAIN BODY ECU) Disconnect the E78 connector from the steering lock actuator assembly. Disconnect the E61 connector from the main body ECU. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E78-4 (SLP1) - E61-18 (SLP) Always Below 1 ohms E78-4 (SLP1) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

This circuit supplies voltage from the battery to terminal B of the steering lock ECU. This circuit is used as power source for the steering lock CPU, motor, communication, and peripheral circuits.

Scheme 82

Scheme 83

1. CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BODY GROUND) Disconnect the E78 connector from the steering lock actuator assembly. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E78-1 (GND) - Body ground Always Below 1 ohms E78-2 (SGND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BATTERY) Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Condition Specified Condition E78-7 (B) - E78-1 (GND) Always 10 to 14 V E78-7 (B) - E78-2 (SGND) Always 10 to 14 V OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (STEERING LOCK ACTUATOR ASSEMBLY - BATTERY)

See also:
• DISASSEMBLY