Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Lexus RC F BaseFACTORY OEM SERVICE PROCEDURE
Section 13 (Front Radar Sensor System - Diagnostic Codes)
WARNING: This page is about a different car, the 2024 Lexus RC F and 2023 Lexus RC F. However, it is still accessible from the selected car via links, so may be relevant.
- Front Radar Sensor System
- Vehicle Control History [01/2023 - ]
- DTC C1A11-00: Front Radar Sensor Optical Axis Misalignment Malfunction [01/2023 - ]
- DTC C1A8C-46: Main Microcomputer in Front Radar Sensor Calibration/Parameter Memory Failure; DTC C1A8D-1C: Power Supply Circuit in Front Radar Sensor Circuit Voltage Out of Range; DTC C1A90-00: Malfunction of Millimeter-wave Circuit in Front Radar Sensor; DTC C1A91-00: Malfunction of Acceleration Sensor in Front Radar Sensor [01/2023 - ]
- DTC U0104-87: Lost Communication with Cruise Control Module Missing Message [01/2023 - ]
- DTC U0305-57: Software Incompatibility with Cruise Control Module Invalid/Incompatible Software Component [01/2023 - ]
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.