AutoCodes – Lexus – C1781 Lexus

C1781 Lexus Code - Steering Angle Sensor Circuit

Quick Answer

The Steering Angle Sensor is fitted to the turn signal switch assembly and detects the steering rotating direction and angle. Common causes include Faulty Steering Angle Sensor, Steering Angle Sensor harness is open or shorted, Steering Angle Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: C1781 Lexus indicates Steering Angle Sensor Circuit.
Common causes: Common causes include Faulty Steering Angle Sensor, Steering Angle Sensor harness is open or shorted, Steering Angle Sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,825

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 26, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C1781 Lexus Description

The Steering Angle Sensor is fitted to the turn signal switch assembly and detects the steering rotating direction and angle. The sensor consists of a slit disc that rotates with the steering wheel as a unit, and a pair of photo interrupters. Each photo interrupter consists of an LED (Light Emitting Diode) and a photo transistor, which face each other. It converts the change in the light irradiation between the 2 elements to the on/off signals. The slit disc rotates between the LED and the photo transistor of the pair of photo interrupters. As the steering wheel is operated, the slit disc rotates with the wheel as a unit to stop and allow light transmission between the 2 elements. The pair of photo interrupters have phases and the suspension ECU detects the steering direction and angle based on the changes of each output. When it is judged that the steering wheel's turning angle is large and the speed is greater than a set value, the ECU causes the damping force to increase.

OBDII Code C1781 Lexus - Steering Angle Sensor Circuit - AutoCodes.com — C1781 Lexus Code - Steering Angle Sensor Circuit

What does this mean?

What are the Possible Causes of the DTC C1781 Lexus?

Faulty Steering Angle Sensor
Steering Angle Sensor harness is open or shorted
Steering Angle Sensor circuit poor electrical connection
Faulty Suspension ECU

How to Fix the DTC C1781 Lexus?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C1781 Lexus code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the C1781 Lexus code?

Need more information on how to fix the C1781 Lexus code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C1781 Lexus Code

1. What are the common symptoms of OBDII code C1781 in a Lexus related to the steering angle sensor circuit?

The common symptoms include the Malfunction Indicator Lamp (MIL) or Check Engine Light illuminating on the dashboard, issues with the vehicle's stability control system, and potential problems with the power steering system.

2. What could cause the OBDII code C1781 to appear in a Lexus?

The code C1781 typically indicates a problem with the steering angle sensor circuit, which could be caused by a faulty steering angle sensor, damaged wiring or connectors, or a malfunction in the electronic control unit (ECU).

3. How can I diagnose the OBDII code C1781 related to the steering angle sensor circuit in my Lexus?

Diagnosis usually involves using a professional OBDII scanner to retrieve the specific trouble code, checking the wiring and connectors for any visible damage, and testing the steering angle sensor itself for proper operation.

4. Can I still drive my Lexus with the OBDII code C1781 present?

While it may be possible to drive the vehicle with this code, it is not recommended, as it may affect the stability control system and compromise overall safety. It is best to address the issue promptly.

5. What are some repair tips for fixing the OBDII code C1781 in a Lexus?

Repair tips may include checking and repairing any damaged wiring or connectors, replacing the steering angle sensor if deemed faulty, and ensuring proper re-calibration of the system after repairs are completed.

6. Is it necessary to visit a dealership or mechanic to fix the OBDII code C1781 in a Lexus?

While it is recommended to seek professional help for accurate diagnosis and repair, some experienced DIYers may be able to address the issue themselves if they have the necessary tools and expertise.

7. How much does it typically cost to repair the OBDII code C1781 in a Lexus?

The cost can vary depending on the exact cause of the issue, the labor rates of the repair shop, and the cost of any replacement parts needed. It is advisable to obtain a few quotes from different mechanics or dealerships.

8. Can resetting the OBDII code C1781 in a Lexus make it go away permanently?

Simply resetting the code may temporarily turn off the Check Engine Light, but if the underlying issue is not addressed, the code is likely to reappear. It is crucial to diagnose and fix the root cause of the problem.

9. What are the potential risks of ignoring the OBDII code C1781 in a Lexus?

Ignoring the code may lead to further damage to the vehicle's steering or stability control systems, compromise safety while driving, and potentially result in more expensive repairs down the line.

10. Are there any recalls or technical service bulletins related to the OBDII code C1781 in Lexus vehicles?

It is advisable to check with Lexus dealerships or visit the National Highway Traffic Safety Administration (NHTSA) website to see if there are any relevant recalls or technical service bulletins related to this specific OBDII code in Lexus vehicles.