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.
2017 Lexus GS FFACTORY OEM SERVICE PROCEDURE
Lane-Keeping Assist System
LANE-KEEPING ASSIST SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC Code | Description |
|---|---|
| C1A01 | Driving Support ECU |
| C1A10 | Front Radar Sensor |
| C1A11 | Front Radar Sensor Incorrect Axial Gap |
| C1A14 | Front Radar Sensor Beam Axis Not Adjusted |
| C1A47 | Steering Angle Sensor |
| C1A48 | G Sensor |
| C1A50 | Brake System Malfunction |
| C1A70 | Power Steering Control System |
| C1A71 | Power Steering Control Torque |
| C1A72 | Communication Error from FCM to Driving Support ECU |
| C1A73 | Driving Support ECU Receive Data Malfunction |
| C1A74 | Steering Vibrator System Malfunction |
| C1A75 | Lost Communication with Steering Vibrator System |
| C1AA0 | Front Camera Module Circuit |
| C1AA1 | FCM Destination Information Unmatched |
| C1AA2 | Vehicle Speed Tolerance Malfunction |
| C1AA3 | Vehicle Speed Sensor Circuit |
| C1AA4 | Yaw Rate Sensor Circuit |
| C1AA5 | Yaw Rate Sensor Power Supply Voltage Circuit |
| C1AA6 | Yaw Rate Sensor Zero Point Malfunction |
| C1AA9 | Front Camera Module Beam Axis Not Adjusted |
| C1AAA | FCM Destination Information Uninitialized |
| C1AAC | Vehicle Information Unmatched |
| C1AAD | Vehicle Information Initialization Incomplete |
| U0100 | Lost Communication With ECM/PCM "A" |
| U0101 | Lost Communication With TCM |
| U0123 | Lost Communication with Yaw Rate Sensor Module |
| U0126 | Lost Communication with Steering Angle Sensor Module |
| U0129 | Lost Communication with Brake System Control Module |
| U0131 | Lost Communication with Power Steering Control Module |
| U0142 | Lost Communication with Body Control Module "B" |
| U0155 | Lost Communication with Combination Meter |
| U0235 | Lost Communication with Cruise Control Front Distance Range Sensor |
| U023A | Lost Communication with Front Camera Module |
| U1104 | Lost Communication with Driving Support ECU |
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.
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