Pre-Collision (Diagnostic Codes & Circuit Tests): Overview Lexus HS I

DESCRIPTION

The seat belt control ECU receives information from the driving support ECU using CAN communication and tightens the seat belt by operating the motor in the front seat outer belt assembly RH.

Scheme 68

The seat belt control ECU receives information from the driving support ECU using CAN communication and tightens the seat belt by operating the motor in the front seat outer belt assembly RH.

The seat belt control ECU receives information from the driving support ECU using CAN communication and tightens the seat belt by operating the motor in the front seat outer belt assembly RH.

The seat belt control ECU receives information from the driving support ECU using CAN communication and tightens the seat belt by operating the motor in the front seat outer belt assembly LH.

Scheme 69

The seat belt control ECU receives information from the driving support ECU using CAN communication and tightens the seat belt by operating the motor in the front seat outer belt assembly LH.

The seat belt control ECU receives information from the driving support ECU using CAN communication and tightens the seat belt by operating the motor in the front seat outer belt assembly LH.

The DTCs above are stored during seat belt control ECU self diagnosis.

HINT

1. When DTC B2015 or B2016 is detected, DTCs B2026 and B2027 will not be detected.
2. When DTC B2020 or B2021 is detected, DTCs B2031 and B2032 will not be detected.

If the seat belt control ECU judges that there is a malfunction in its internal circuit as a result of self-diagnosis, or if the power source voltage (+B) is not input to the seat belt control ECU, this DTC will be stored.

This DTC is stored when a malfunction in the electronically controlled brake system is detected. This circuit consists of the brake booster with master cylinder (skid control ECU) and seat belt control ECU. Signals are sent from the brake booster with master cylinder (skid control ECU) using CAN communication.

The seat belt control ECU is connected to the main body ECU using CAN communication.

The seat belt control ECU receives vehicle model information from the main body ECU and determines whether the seat belt buckle switch information from the center airbag sensor assembly is for the driver seat or the front passenger seat.

DTC B2064 is stored when the CAN communication frame with the main body ECU is normal and communication is available, but the steering wheel position information is not set or varies.

These DTCs are stored when a malfunction is detected in the driver side seat buckle switch circuit or passenger side seat belt buckle switch circuit.

Scheme 70

This DTC is stored when CAN communication between the driving support ECU and brake booster with master cylinder (skid control ECU) is interrupted.

This circuit consists of the driving support ECU, brake booster with master cylinder (skid control ECU) and seat belt control ECU. DTC B2085 is stored when the seat belt control ECU detects an interruption in CAN communication between the driving support ECU and brake booster with master cylinder (skid control ECU).

The seat belt control ECU receives collision information from the driving support ECU and brake booster with master cylinder (skid control ECU) via CAN communication, and tightens the seat belts by operating the motor inside the front seat outer belt assembly.

When the driving support ECU detects a malfunction in the dynamic radar cruise control system and pre-collision system, the malfunction information is sent to the seat belt control ECU, which outputs this DTC.

When DTC B2090 is detected, other DTCs are also stored by the driving support ECU (dynamic radar cruise control system and pre-collision system).

The driving support ECU uses the millimeter wave radar sensor assembly and lane recognition camera sensor assembly to detect obstacles in front of the vehicle.

Based on this information, the driving support ECU calculates the risk of a collision and operates the pre-collision system when it determines that the risk is high.

When a new driving support ECU is installed, it receives vehicle specification information (destination, steering wheel position, 2WD or AWD information, etc.) from the main body ECU and memorizes the information.

DTC C1A02 is stored when the driving support ECU receives the vehicle specification information from the main body ECU but cannot store it.

The driving support ECU uses the millimeter wave radar sensor assembly and lane recognition camera sensor assembly to detect obstacles in front of the vehicle.

Based on this information, the driving support ECU sends pre-collision control operation signals.

When the millimeter wave radar sensor assembly is replaced with a new one, it acquires the country specification information from the driving support ECU. Also, when the driving support ECU is replaced with a new one, it receives country specification information from the main body ECU. When country specification information in the sensor, ECU and/or main body ECU do not match, DTC C1A0A is stored.

When the lane recognition camera sensor assembly is replaced with a new one, it acquires the country specification information from the driving support ECU. The lane recognition camera sensor assembly has information about the market it is intended for use in (country specification information such as the destination, steering wheel position, etc.). When a new lane recognition camera sensor assembly is installed and the country specification information does not match that of the driving support ECU, the ECU stores DTC C1A0C.

The driving support ECU uses the millimeter wave radar sensor assembly and lane recognition camera sensor assembly to detect obstacles in front of the vehicle.

Based on this information, the driving support ECU sends pre-collision control operation signals.

When the driving support ECU receives information that there is a malfunction in the millimeter wave radar sensor, DTC C1A10 is stored.

The driving support ECU uses the millimeter wave radar sensor assembly and lane recognition camera sensor assembly to detect obstacles in front of the vehicle.

Based on this information, the driving support ECU sends pre-collision control operation signals.

When the vehicle is determined to be driving in a straight line or on a slow curve based on signals from the yaw rate sensor etc., the millimeter wave radar sensor assembly performs a self diagnosis to check if the sensor beam axis is deviated from the vehicle movement direction. When the millimeter wave radar sensor beam axis is deviated, the driving support ECU detects this, and stores DTC C1A11.

After installing a new millimeter wave radar sensor assembly, if the sensor beam axis adjustment is not performed, DTC C1A14 is stored.

When the driving support ECU receives information that there is a malfunction in the lane recognition camera sensor assembly, DTC C1A20 is stored.

If the driving support ECU determines that the lane recognition camera sensor assembly axis is deviated, DTC C1A22 is stored. Also, if the lane recognition camera sensor assembly beam axis adjustment is not performed after installing the lane recognition camera sensor assembly, DTC C1A23 is stored.

The driving support ECU uses the millimeter wave radar sensor assembly, driver monitor camera and lane recognition camera sensor assembly to detect obstacles in front of the vehicle, and detect the direction that the driver's head is facing. Based on this information, the driving support ECU sends pre-collision control operation signals.

When the driving support ECU receives information that there is a malfunction in the driver monitor ECU, DTC C1A30 is stored.

The driving support ECU uses the millimeter wave radar sensor assembly, driver monitor camera and lane recognition camera sensor assembly to detect obstacles in front of the vehicle, and detect the direction that the driver's head is facing. Based on this information, the driving support ECU sends pre-collision control operation signals.

When the driving support ECU receives information that there is a malfunction in the driver monitor camera, DTC C1A31 is stored.

Scheme 71

1. INSPECT DRIVER MONITOR CAMERA (POWER SOURCE) Turn the power switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition 6 (CB+) - Body ground Power switch on (IG) 5.5 to 6.5 V TEXT IN ILLUSTRATION *1 Component without harness connected (Driver Monitor ECU) NG --> See step 5 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (DRIVER MONITOR CAMERA - DRIVER MONITOR ECU) Disconnect the driver monitor camera connector. Disconnect the driver monitor ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F112-1 (CB+) - F111-6 (CB+) Always Below 1 ohms F112-2 (CGND) - F111-8 (CGND) Always Below 1 ohms F112-1 (CB+) or F111-6 (CB+) - Body ground Always 10 kohms or higher F112-2 (CGND) or F111-8 (CGND) - Body ground Always 10 kohms or higher Reconnect the driver monitor camera and driver monitor ECU connectors. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVER MONITOR CAMERA - DRIVER MONITOR ECU) OK: Go to next step
3. REPLACE DRIVER MONITOR CAMERA Replace the driver monitor camera. Refer to «REMOVAL»(ref-398296-S23721350542011051600000) . NEXT: Go to next step
4. CHECK FOR DTC Using the Techstream, enter the following menus: Body Electrical / Pre-Collision2 / Trouble Codes. Clear the DTCs. Refer to «DTC CHECK / CLEAR»(ref-398341-S04426416572011051600000) . Turn the power switch off. Turn the power switch on (IG). Drive the vehicle. Recheck for DTC. OK DTC C1A31 is not output. NG --> See step 5 OK --> END
5. REPLACE DRIVER MONITOR ECU. Refer to «REMOVAL»(ref-398296-S20723478812011051600000)

The brake booster with master cylinder (skid control ECU) receives vehicle stability signals from the yaw rate sensor and sends the signals to the driving support ECU. If the brake booster with master cylinder (skid control ECU) detects that the yaw rate sensor is malfunctioning, the brake booster with master cylinder (skid control ECU) sends a malfunction signal to the driving support ECU, and the driving support ECU stores DTC C1A46. Also, when DTC C1A46 is stored, the brake booster with master cylinder (skid control ECU) stores DTC for brake system at the same time.

The brake booster with master cylinder (skid control ECU) receives steering rotation angle information from the steering angle sensor, and sends the information to the driving support ECU through the CAN communication line.

If the brake booster with master cylinder (skid control ECU) detects a malfunction of the steering angle sensor, it sends a malfunction signal to the driving support ECU and stores DTC C1A47.

Based on pre-collision control, the driving support ECU communicates to the driver to be careful. The driving support ECU performs this by sending a sounding signal to the brake booster with master cylinder (skid control ECU) to sound the skid control buzzer.

When the brake booster with master cylinder (skid control ECU) detects a malfunction in the VSC warning buzzer circuit, a malfunction signal is sent to the driving support ECU, and DTC C1A4A is stored. Although the brake booster with master cylinder (skid control ECU) sends a malfunction signal to the driving support ECU, the vehicle stability control system does not store a relevant malfunction detection DTC.

The stop light switch assembly sends a brake pedal operation signal to the driving support ECU. Based on the signal, the driving support ECU cancels cruise control.

1. The driving support ECU uses the millimeter wave radar sensor assembly to detect obstacles in front of the vehicle. Based on this information, the driving support ECU sends pre-collision control operation signals. These DTCs are stored when a communication malfunction occurs between the sensors and ECUs that detect collisions, or between ECUs that perform the pre-collision control.

1. The driving support ECU sends vehicle speed and vehicle condition information to the millimeter wave radar sensor assembly. The millimeter wave radar sensor assembly then sends information on the presence, distance, and relative speed of objects ahead to the driving support ECU. The driving support ECU sends this information to the hybrid vehicle control ECU and performs pre-collision system (DTC U1104). DTC No. DTC Detection Condition Trouble Area U0122 When the power switch is on (IG), a communication error between the brake booster with master cylinder (skid control ECU) and driving support ECU is detected for approx. 1 second. When the power switch is on (IG), a communication error between the skid control ECU assembly and seat belt control ECU is detected for approx. 2 seconds. Brake booster with master cylinder (skid control ECU) CAN communication system Seat belt control ECU Driving support ECU U0123 When the power switch is on (IG), a communication error between the yaw rate sensor and driving support ECU is detected for approx. 1 second. Yaw rate sensor CAN communication system Driving support ECU U0126 When the power switch is on (IG), a communication error between the steering angle sensor and driving support ECU is detected for approx. 1 second. Steering angle sensor CAN communication system Driving support ECU U0140 When the power switch is on (IG), communication stop between main body ECU and seat belt control ECU continues for approx. 5 seconds or more. Main body ECU CAN communication system Seat belt control ECU U0151 When the power switch is on (IG), communication stop between center airbag sensor and seat belt control ECU continues for approx. 5 seconds or more. Center airbag sensor CAN communication system Seat belt control ECU U0235 When the power switch is on (IG), a communication error between the millimeter wave radar sensor and driving support ECU is detected for approx. 1 second. Communication circuit Millimeter wave radar sensor assembly Driving support ECU U0293 When the power switch is on (IG), a communication error between the driving support ECU and brake booster with master cylinder (skid control ECU) is detected for approx. 1 second. When the power switch is on (IG), a communication error between the hybrid vehicle control ECU and driving support ECU is detected for approx. 1 second. Hybrid vehicle control ECU Brake booster with master cylinder (skid control ECU) CAN communication system Driving support ECU U1002 When the power switch is on (IG), communication stop between the lane recognition camera sensor assembly, millimeter wave radar sensor and driving support ECU continues for 1 second or more. Lane recognition camera sensor assembly Millimeter wave radar sensor assembly CAN communication system Driving support ECU U1100 When the power switch is on (IG), a communication error between the seat belt control ECU and driving support ECU is detected for approx. 1 second. Seat belt control ECU CAN communication system Driving support ECU U1104 When the power switch is on (IG), a communication error between the driving support ECU and seat belt control ECU is detected for approx. 1 second. When the power switch is on (IG), a communication error between the driving support ECU and hybrid vehicle control ECU is detected for approx. 1 second. Communication circuit Millimeter wave radar sensor assembly Driving support ECU Seat belt control ECU CAN communication system U1121 When the power switch is on (IG), communication stop between the driver monitor ECU and driving support ECU continues for 1 second or more. Driver monitor ECU CAN communication system Driving support ECU

Scheme 72

The driving support ECU uses the millimeter wave radar sensor assembly and lane recognition camera sensor assembly to detect obstacles in front of vehicle.

Because of the location of the lane recognition camera assembly, it is subject to high temperatures. If the lane recognition camera sensor assembly becomes too hot, the power source is shut down to protect the system. At that time CAN communication also stops. However, in order to inform the driving support ECU that CAN communication has not stopped because of a CAN communication error, on/off signals are periodically sent from the HITP terminal.

Scheme 73

The driving support ECU receives pre-collision brake on/off signal from the pre-collision system cancel switch.

Scheme 74

Scheme 75

Scheme 76

1. READ VALUE USING TECHSTREAM (PRE-COLLISION BRAKE CANCEL SWITCH) Use the Data List to check if the pre-collision brake cancel switch is functioning properly. PRE-COLLISION 2 Tester Display Measurement Item/Range Normal Condition Diagnostic Note Pre-Collision Brake OFF Switch Pre-collision system cancel switch signal/ON or OFF ON: Pre-collision brake cancel switch on OFF: Pre-collision brake cancel switch off - OK On screen, each item changes between ON and OFF according to above chart. NG --> See step 2 OK --> See step 5
2. INSPECT PRE-COLLISION BRAKE CANCEL SWITCH ASSEMBLY Remove the pre-collision brake cancel switch assembly. Refer to «REMOVAL»(ref-398296-S29305562632011051600000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 1 - 2 Pressed Below 1 ohms Not pressed 10 kohms or higher TEXT IN ILLUSTRATION *1 Component without harness connected (Pre-collision Brake Cancel Switch Assembly) Reinstall the pre-collision brake cancel switch assembly. Refer to «INSTALLATION»(ref-398296-S40177147852011051600000) . NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (PRE-COLLISION BRAKE CANCEL SWITCH - DRIVING SUPPORT ECU) Disconnect the pre-collision brake cancel switch assembly connector. Disconnect the driving support ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F100-1 - F102-5 (PBSW) Always Below 1 ohms F100-1 or F102-5 (PBSW) - Body ground Always 10 kohms or higher Reconnect the pre-collision brake cancel switch assembly connector and driving support ECU connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (PRE-COLLISION BRAKE CANCEL SWITCH - DRIVING SUPPORT ECU) OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (PRE-COLLISION BRAKE CANCEL SWITCH ASSEMBLY - BODY GROUND) Disconnect the pre-collision brake cancel switch assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F100-2 - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Pre-collision Brake Cancel Switch Assembly) Reconnect the pre-collision brake cancel switch assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (PRE-COLLISION BRAKE CANCEL SWITCH ASSEMBLY - BODY GROUND) OK --> See step 7
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-398341-S35018460362011051600000)
6. REPLACE PRE-COLLISION BRAKE CANCEL SWITCH ASSEMBLY. Refer to «REMOVAL»(ref-398296-S29305562632011051600000)
7. REPLACE DRIVING SUPPORT ECU. Refer to «REMOVAL»(ref-398095-S30328724522011051600000)

This circuit supplies power to the seat belt control ECU.

Scheme 77

See also:
• REMOVAL