C1A47 on Lexus: How to Diagnose & Fix
Manufacturer-Specific Steering Angle / Torque Sensor Circuit (EPS)
1 Lexus model · 1 documented issue
C1A47 on Lexus by model: symptoms, diagnosis and fix
Some owners report intermittent pre-collision system, radar cruise, or lane-support warnings on 2023-2025 Lexus IS models, often after heavy rain, road grime buildup, windshield contamination, or minor front-end impacts. The system may temporarily disable with a message indicating the camera or radar is unavailable, even though no permanent hardware failure exists. In other cases, sensor alignment or calibration drift after windshield or bumper work can trigger recurring warnings.
Common Symptoms
- Pre-Collision System unavailable warning
- Radar cruise temporarily disabled
- Lane assist warning messages
- ADAS warnings in rain or after car wash
- Intermittent master warning light
How to Fix
Inspect and clean the front radar emblem area and windshield camera zone first, then scan for stored ADAS-related codes. If warnings persist, perform radar/camera aiming and calibration, especially after windshield replacement, bumper repair, or alignment work. Replace the affected sensor only after confirming power, communication, and calibration status.
Owner tips & cautions
- TipClean the radar emblem and the windshield area in front of the camera before assuming a failed sensor.
C1A47 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does C1A47 mean on a Lexus?
C1A47 stands for "Manufacturer-Specific Steering Angle / Torque Sensor Circuit (EPS)." C1A47 is a manufacturer-specific chassis code generally tied to the Electric Power Steering system, commonly involving the steering angle or steering torque sensor circuit. The power steering ECU relies on these sensors (and often the clock spring/spiral cable connection) to know how far and how hard the driver is turning the wheel; this code sets when that signal is missing, implausible, or out of range. The precise definition varies by manufacturer. When set, power steering assist may be reduced and steering can feel heavier than normal. On Lexus it is documented across 1 model: IS.
What are the most common causes of C1A47?
The most common causes of C1A47 are: Faulty steering angle or torque sensor, Damaged clock spring / spiral cable in the steering column, Connector or wiring fault at the steering sensor, Sensor calibration lost after battery or steering work, Failed EPS control module, Steering angle sensor not zeroed/initialized. The specific cause varies by vehicle.
How much does it cost to fix C1A47 on a Lexus?
Repair costs vary widely with the root cause and Lexus model; each issue on this page carries its own estimate where one is published.
Looking for C1A47 on a different make?
View C1A47 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.