Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
NOTICE:
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Before replacing the ECM, refer to Registration.
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- When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle and a DTC may be stored.
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When the millimeter wave radar sensor assembly has been replaced with a new one, it is necessary to perform millimeter wave radar sensor assembly adjustment and front radar acceleration sensor calibration, and to clear the vehicle control history.
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- When replacing the forward recognition camera, replace it with a new one. If a forward recognition camera which was installed to another vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle and a DTC may be stored.
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If the forward recognition camera has been replaced with a new one or the windshield glass has been removed and installed, it is necessary to perform forward recognition camera adjustment.
HINT:
Forward recognition camera adjustment can be performed by using either One Time Recognition or Sequential Recognition.
One Time Recognition: Click here
Sequential Recognition: Click here
HINT:
- Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
- Inspect the fuses and relays related to this system before inspecting the suspected areas below.
- Determine the problem systems, then perform the respective inspection procedures.
- By using the vehicle control history, various control parameter history can be checked.
| Symptom | Suspected Area | Link |
|---|---|---|
| The dynamic radar cruise control system cannot be turned on using the cruise control main switch | CAN communication system | |
| Cruise control switch circuit | | |
| Cruise main indicator light circuit | | |
| Forward recognition camera | | |
| ECM | | |
| The dynamic radar cruise control mode cannot be changed between vehicle-to-vehicle distance control mode and constant speed control mode | CAN communication system | |
| Cruise control switch circuit | | |
| ECM | | |
| The vehicle-to-vehicle distance cannot be changed | CAN communication system | |
| Distance control switch circuit | | |
| Forward recognition camera | | |
| Vehicle speed setting cannot be performed (in constant speed control mode) | Fail-safe chart | |
| CAN communication system | | |
| Cruise control switch circuit | | |
| Stop light switch circuit | | |
| Automatic transaxle system (for U881E) | | |
| Automatic transaxle system (for U881F) | | |
| Vehicle stability control system | | |
| Forward recognition camera | | |
| ECM | | |
| Vehicle speed setting cannot be performed (in vehicle-to-vehicle distance control mode) | Front Radar Sensor Temporary Unavailable (Optical Axis Misalignment) history* | |
| Fail-safe chart | | |
| Forward recognition camera is temporarily unavailable | | |
| Millimeter wave radar sensor assembly is dirty | | |
| Millimeter wave radar sensor assembly beam axis not adjusted | | |
| CAN communication system | | |
| Cruise control switch circuit | | |
| Automatic transaxle system (for U881E) | | |
| Automatic transaxle system (for U881F) | | |
| Millimeter wave radar sensor assembly | | |
| Forward recognition camera | | |
| Vehicle stability control system | | |
| ECM | | |
| Control of vehicle speed by the dynamic radar cruise control system is canceled (in constant speed control mode) | Fail-safe chart | |
| CAN communication system | | |
| Cruise control switch circuit | | |
| Stop light switch circuit | | |
| Automatic transaxle system (for U881E) | | |
| Automatic transaxle system (for U881F) | | |
| Vehicle stability control system | | |
| ECM | | |
| Control of vehicle speed by the dynamic radar cruise control system is canceled (in vehicle-to-vehicle distance control mode) | Fail-safe chart | |
| Forward recognition camera is temporarily unavailable | | |
| Millimeter wave radar sensor assembly is dirty | | |
| Millimeter wave radar sensor assembly beam axis not adjusted | | |
| CAN communication system | | |
| Cruise control switch circuit | | |
| Automatic transaxle system (for U881E) | | |
| Automatic transaxle system (for U881F) | | |
| Millimeter wave radar sensor assembly | | |
| Forward recognition camera | | |
| Vehicle stability control system | | |
| ECM | | |
| Hunting/vehicle speed is not constant (in constant speed control mode) | CAN communication system | |
| Vehicle stability control system | | |
| ECM | | |
| Hunting/vehicle speed is not constant (in vehicle-to-vehicle distance control mode) | Millimeter wave radar sensor assembly is dirty | |
| Millimeter wave radar sensor assembly beam axis not adjusted | | |
| CAN communication system | | |
| Vehicle stability control system | | |
| Millimeter wave radar sensor assembly | | |
| ECM | | |
| Vehicle speed control by the dynamic radar cruise control system is not canceled when the CANCEL switch is pushed | Cruise control switch circuit | |
| ECM | | |
| Moving the shift lever does not cancel control of vehicle speed by the dynamic radar cruise control system | Park/neutral position switch assembly (for U881E) | |
| Park/neutral position switch assembly (for U881F) | | |
| Transmission floor shift assembly (for U881E) | | |
| Transmission floor shift assembly (for U881F) | | |
| Automatic transaxle system (for U881E) | | |
| Automatic transaxle system (for U881F) | | |
| ECM | | |
| Vehicle speed control by the dynamic radar cruise control system is not canceled when a shift paddle switch is operated | Automatic transaxle system (for U881E) | |
| Automatic transaxle system (for U881F) | | |
| Shift paddle switch circuit (for U881E) | | |
| Shift paddle switch circuit (for U881F) | | |
| ECM | | |
| Depressing the brake pedal does not cancel control of vehicle speed by the dynamic radar cruise control system | Stop light switch circuit | |
| ECM | | |
| Control cannot be canceled while the vehicle is stopped | CAN communication system | |
| Vehicle stability control system | | |
| Electric parking brake system | | |
| Seat belt warning system | | |
| Door courtesy switch circuit | | |
| ECM | | |
| Control cannot be canceled by operating the parking brake | Electric parking brake system | |
| CAN communication system | | |
| Skid control ECU (brake actuator assembly) | | |
| ECM | | |
| Even though the millimeter wave radar sensor assembly and forward recognition camera are not dirty, the warning message "Radar Cruise Control Unavailable See Owner's Manual" is displayed | Millimeter wave radar sensor assembly | |
| Forward recognition camera | | |
| The vehicle approach warning buzzer does not sound | Skid control buzzer assembly | |
| Check millimeter wave radar sensor assembly installation position | | |
| Check installation of forward recognition camera | | |
| Forward recognition camera | | |
| Millimeter wave radar sensor assembly | | |
| Even though the vehicle approach warning buzzer is sounding, brake control is not performed to decelerate the vehicle | Vehicle stability control system | |
| CAN communication system | | |
| Forward recognition camera | | |
| ECM | | |
| Even though the SET function is operating, the cruise SET indicator does not illuminate | CAN communication system | |
| Cruise SET indicator light circuit | | |
| ECM | | |
| The cruise control indicator remains illuminated | CAN communication system | |
| Cruise main indicator light circuit | | |
| ECM | | |
| Indicators are not displayed on the multi-information display in the combination meter assembly | CAN communication system | |
| ECM | | |
| A buzzer does not sound when control of vehicle speed by the dynamic radar cruise control is canceled | CAN communication system | |
| ECM | |
- *: When "Radar Cruise Control Unavailable" is displayed and there is "Front Radar Sensor Temporary Unavailable (Optical Axis Misalignment)" history, the beam axis of the millimeter wave radar sensor assembly may be being aligned. In this case, wait for beam axis alignment to complete. When beam axis alignment is complete, "Radar Cruise Control Unavailable" stops being displayed.
Operation Check
OPERATION CHECK INPUT SIGNAL CHECK (a) Connect the Techstream to the DLC3. (b) Check the cruise control main switch using the Data List function of the Techstream (ON-OFF, -SET, +RES and CANCEL). ...
Diagnosis System
DIAGNOSIS SYSTEM DIAGNOSIS FUNCTION (a) The diagnosis function turns off the cruise control indicator, illuminates the master warning light and displays a warning message when a malfunction is detecte ...
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
- For your information
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- Instrument cluster
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- When trouble arises
- Vehicle specifications
- For owners
Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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