LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2021 >> RX 350L FWD >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> Pre-Collision System - Diagnostics - Introduction >> Pre-Collision System >> How To Proceed With Troubleshooting [08/2019 - ] >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

How To Proceed With Troubleshooting [08/2019 - ]: Procedure

  1. VEHICLE BROUGHT TO WORKSHOP 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  2

  2. PRE-CHECK 
    1. 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.

    2. Check the fuses and relays.
    3. Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  3

  3. INSPECT MULTI-INFORMATION DISPLAY 
    1. Check if a pre-collision system warning message is displayed on the multi-information display in the combination meter assembly.

      HINT: 

      If more than one message is displayed, perform each inspection in the order listed in the table.

      Result

      Result Proceed to
      "VSC Turned OFF Pre-Collision Brake System Unavailable" is displayed A
      "Pre-Collision System Malfunction Visit Your Dealer" is displayed B
      Any of the following messages is displayed:
      • "Pre-Collision System Unavailable"
      • "Pre-Collision System Unavailable Clean Sensor"
      • "Front Camera Unavailable"
      • "Front Camera Unavailable See Owner's Manual"
      		 C
      Warning message is not displayed D

    Result: 

    A 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2019 - ]  

    Result: 

    C 

    See step  6

    Result: 

    D 

    See step  9

    Result: 

    B 

    See step  4

  4. CHECK CAN COMMUNICATION SYSTEM* 
    1. Using the Techstream, check if the CAN communication system is functioning normally.

      HINT: 

      Refer to CAN Bus Check in CAN Communication System.

      Refer to DIAGNOSIS SYSTEM [08/2019 - ]

      OK

      CAN communication system is functioning normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2015 - ] 

    Result: 

    OK 

    See step  5

  5. CHECK FOR DTCs* 
    1. Using the Techstream, check for DTCs.

      Body Electrical > Pre-Collision System > Trouble Codes 

    2. Make a note of the output DTCs.

      Result

      Result Proceed to
      DTCs are not output A
      DTC C1425-71 is output B
      DTCs other than C1425-71 are output C

    Result: 

    B 

    GO TO DTC CHART (C1425-71). Refer to  DTC C1425-71: Stop Light Relay Actuator Stuck [08/2019 - ] 

    Result: 

    C 

    See step  7

    Result: 

    A 

    See step  6

  6. CHECK VEHICLE CONTROL HISTORY* 
    1. Using the Techstream, check for Vehicle Control History (RoB).

      Body Electrical > Pre-Collision System > Utility 

      Tester Display
      Vehicle Control History (RoB)
    2. Record any output Vehicle Control History (RoB).

      Result

      Result Proceed to
      Vehicle Control History (RoB) codes are not output A
      Vehicle Control History (RoB) code X2006, X2013, X2015, X2022, X2024, X2025, X2026 or X2028 is output B
      Vehicle Control History (RoB) codes other than X2006, X2013, X2015, X2022, X2024, X2025, X2026 and X2028 are output C

    Result: 

    A 

    GO TO SYMPTOM SIMULATION. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

    Result: 

    B 

    GO TO VEHICLE CONTROL HISTORY (X2006, X2013, X2015, X2022, X2024, X2025, X2026 or X2028). Refer to  VEHICLE CONTROL HISTORY [08/2019 - ] 

    Result: 

    C 

    See step  8

  7. RECONFIRM DTC OUTPUT* 
    1. Using the Techstream, clear the DTCs.

      Body Electrical > Pre-Collision System > Clear DTCs 

    2. 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.

      Refer to DIAGNOSTIC TROUBLE CODE CHART [08/2019 - ] 

    3. Using the Techstream, check for DTCs.

      Body Electrical > Pre-Collision System > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      DTCs are output B

    Result: 

    A 

    GO TO SYMPTOM SIMULATION. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2019 - ]  

  8. RECONFIRM VEHICLE CONTROL HISTORY* 
    1. Using the Techstream, clear the Vehicle Control History (RoB).

      Body Electrical > Pre-Collision System > Utility 

      Tester Display
      Vehicle Control History (RoB)
    2. Using the Techstream, check for Vehicle Control History (RoB).

      Body Electrical > Pre-Collision System > Utility 

      Tester Display
      Vehicle Control History (RoB)

      Result

      Result Proceed to
      Vehicle Control History codes (RoB) are not output A
      Vehicle Control History codes (RoB) are output B

    Result: 

    A 

    GO TO SYMPTOM SIMULATION. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

    Result: 

    B 

    GO TO VEHICLE CONTROL HISTORY. Refer to  VEHICLE CONTROL HISTORY [08/2019 - ] 

  9. PROBLEM SYMPTOMS TABLE 
    1. Refer to Problem Symptoms Table for the pre-collision system.

      Refer to PROBLEM SYMPTOMS TABLE [08/2019 - ] 

      Result

      Result Proceed to
      Problem symptoms are not listed in the Problem Symptoms Table. A
      Problem symptoms are listed in the Problem Symptoms Table. B

    Result: 

    B 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2019 - ]  

    Result: 

    A 

    See step  10

  10. INSPECT WARNING LIGHT 
    1. Check the condition of the warning lights.

      Result

      Result Proceed to
      The PCS warning light is not illuminated A
      Only the PCS warning light is illuminated B

    Result: 

    B 

    GO TO VEHICLE CONTROL HISTORY (X2015). Refer to  VEHICLE CONTROL HISTORY [08/2019 - ] 

    Result: 

    A 

    See step  11

  11. CHECK FOR DTCs* (Confirmed) 
    1. Using the Techstream, check for DTCs (Confirmed).

      Body Electrical > Pre-Collision System > Trouble Codes 

    2. Make a note of the output DTCs (Confirmed).

      Result

      Result Proceed to
      DTCs (Confirmed) are not output A
      DTCs (Confirmed) are output B

    Result: 

    B 

    See step  15

    Result: 

    A 

    See step  12

  12. CHECK VEHICLE CONTROL HISTORY* 
    1. Using the Techstream, check for Vehicle Control History (RoB).

      Body Electrical > Pre-Collision System > Utility 

      Tester Display
      Vehicle Control History (RoB)
    2. Record any output Vehicle Control History (RoB).

      Result

      Result Proceed to
      Vehicle Control History codes (RoB) are not output A
      Vehicle Control History codes (RoB) are output B

    Result: 

    B 

    GO TO VEHICLE CONTROL HISTORY 

    Refer to VEHICLE CONTROL HISTORY [08/2019 - ]

    HINT: 

    By using information obtained from the customer problem analysis and vehicle control history such as time of detection, trip number, etc., it may be possible to determine the cause of the malfunction.

    Result: 

    A 

    See step  13

  13. CHECK CONDITIONS WHEN PRE-COLLISION SYSTEM DID NOT OPERATE 
    1. Check if the exception conditions for the pre-collision system were met.

      Refer to PRECAUTION [08/2019 - ] 

      Result

      Result Proceed to
      The exception conditions were not met. A
      The exception conditions were met. B

    Result: 

    B 

    END (The pre-collision system operated accordingly with the operation and prohibition conditions.) 

    Result: 

    A 

    See step  14

  14. INSPECT MILLIMETER WAVE RADAR SENSOR ASSEMBLY (BEAM AXIS MISALIGNMENT READING)* 
    NOTE:

    Before checking for millimeter wave radar sensor beam axis misalignment, make sure that the radiator grille and front bumper are correctly installed and have not been damaged or modified.

    1. Adjust the reflector height.

      Refer to ADJUSTMENT [08/2019 - ]

    2. Place the reflector.

      Refer to ADJUSTMENT [08/2019 - ]

    3. Connect the Techstream to the DLC3.
    4. Turn the engine switch on (IG).
    5. Turn the Techstream on.
    6. Enter the following menus: Body Electrical / Front Radar Sensor / Utility / Front Beam Axis Misalignment Reading.

      Body Electrical > Front Radar Sensor > Utility 

      Tester Display
      Front Beam Axis Misalignment Reading
    7. Check the amount of misalignment.

      Standard

      Vertical Direction -5 to 5 deg.
      Horizontal Direction -0.6 to 0.6 deg.

      Result

      Result Proceed to
      The beam axis values are within specification. A
      The beam axis values are not within specification. B

    Result: 

    A 

    GO TO SYMPTOM SIMULATION. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

    Result: 

    B 

    ADJUST MILLIMETER WAVE RADAR SENSOR ASSEMBLY. Refer to  ADJUSTMENT [08/2019 - ] 

  15. GO TO DTC CHART 
    1. Refer to each corresponding DTC (Confirmed) for details on the detection conditions.

      Refer to DIAGNOSTIC TROUBLE CODE CHART [08/2019 - ] 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

    Explain to the customer the cause of the previously stored DTC and that the output reason has been cleared.

scientia non olet · About LEMON Manuals