Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: How To Proceed With Troubleshooting

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Engine & Hybrid System / Cruise Control / Road Sign Assist System / How To Proceed With Troubleshooting

CAUTION / NOTICE / HINT

HINT:

  • Before performing troubleshooting for the road sign assist system, make sure that the pre-collision system and lane control system are not malfunctioning.

    Pre-collision system: Click here

    Lane control system: Click here

  • Perform the following procedure to troubleshoot the road sign assist system.
  • *: Use the Techstream.

PROCEDURE

1.

VEHICLE BROUGHT TO WORKSHOP
NEXT

2.

CUSTOMER PROBLEM ANALYSIS

HINT:

  • In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
  • Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases.
  • The following 5 items are important points for problem analysis:

    What

    Vehicle model, system name

    When

    Date, time, occurrence frequency

    Where

    Road conditions

    Under what conditions?

    Driving conditions, weather conditions

    How did it happen?

    Problem symptoms
NEXT

3.

PRE-CHECK

(a) Measure the battery voltage.

Standard Voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step.

(b) Check the fuses and relays.

(c) Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc.

NEXT

4.

CHECK COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM*

(a) Using the Techstream, check for CAN communication system DTCs.

Click here

Result

Proceed to

CAN DTCs are not output

A

CAN DTCs are output

B
B

GO TO CAN COMMUNICATION SYSTEM

A

5.

CHECK FOR DTCs*

(a) Using the Techstream, Check for DTCs.

Body Electrical > Road Sign Assist > Trouble Codes

(b) Make a note of the output DTCs.

Result

Proceed to

DTCs are not output

A

DTCs are output

B
A

GO TO STEP 7

B

6.

RECONFIRM DTC OUTPUT*

(a) Using the Techstream, Clear the DTCs.

Body Electrical > Road Sign Assist > Clear DTCs

(b) Reproduce the vehicle conditions that were present when the DTCs that were noted were stored.

HINT:

Refer to each corresponding DTC for details on the detection conditions.

Click here

(c) Using the Techstream, check for DTCs.

Body Electrical > Road Sign Assist > Trouble Codes

Result

Proceed to

DTCs are not output

A

DTCs are output

B
B

GO TO DIAGNOSTIC TROUBLE CODE CHART

A

7.

CHECK VEHICLE CONTROL HISTORY*

(a) Using the Techstream, check for Vehicle Control History (RoB).

Body Electrical > Road Sign Assist > Utility

Tester Display

Vehicle Control History (RoB)

(b) Make a note of the output Vehicle Control History (RoB).

Result

Proceed to

Vehicle Control History (RoB) is not output

A

Vehicle Control History (RoB) is output

B
A

GO TO SYMPTOM SIMULATION

B

8.

RECONFIRM VEHICLE CONTROL HISTORY*

(a) Using the Techstream, clear the Vehicle Control History (RoB).

Body Electrical > Road Sign Assist > Utility

Tester Display

Vehicle Control History (RoB)

(b) Using the Techstream, check for Vehicle Control History (RoB).

Body Electrical > Road Sign Assist > Utility

Tester Display

Vehicle Control History (RoB)

Result

Proceed to

Vehicle Control History (RoB) is not output

A

Vehicle Control History (RoB) is output

B
A

GO TO SYMPTOM SIMULATION

B

GO TO VEHICLE CONTROL HISTORY

    Parts Location
    PARTS LOCATION ILLUSTRATION *1 MILLIMETER WAVE RADAR SENSOR ASSEMBLY *2 FORWARD RECOGNITION CAMERA *3 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) *4 ECM ILLUSTRATION *A for ...

    Utility
    UTILITY NOTICE: If the forward recognition camera has been replaced due to a malfunction in the road sign assist system, be sure to perform forward recognition camera adjustment. Otherwise all systems ...

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    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Road Sign Assist System: Freeze Frame Data
    FREEZE FRAME DATA DESCRIPTION (a) Whenever a road sign assist system DTC is stored, the forward recognition camera stores the current vehicle state (ECU and sensor information) as Freeze Frame Data. CHECK FREEZE FRAME DATA (a) Connect the Techstream to the DLC3. (b) Turn the engine switch on (IG). ( ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

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