AutoCodes – Generic – C1781

C1781 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 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 5,109

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

What does this mean?

What are the Possible Causes of the DTC C1781?

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?

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 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 code?

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

Need Help with the Code?

Get the C1781 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C1781 Lexus — Steering Angle Sensor Circuit
C1781 Toyota — Steering Angle Sensor Circuit

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 Code

1. What are the common symptoms of OBDII code C1781 (Steering Angle Sensor Circuit)?

The common symptoms of OBDII code C1781 include the ABS warning light coming on, stability control system malfunctions, and potential loss of power steering assistance.

2. What are possible causes of OBDII code C1781?

Possible causes of OBDII code C1781 include a faulty steering angle sensor, damaged wiring or connectors in the steering angle sensor circuit, or a malfunctioning electronic control unit (ECU).

3. How can I diagnose the issue related to OBDII code C1781?

Diagnosing the issue related to OBDII code C1781 involves using a diagnostic scanner to read the code, checking the wiring and connectors for any damage, and testing the steering angle sensor for proper functionality.

4. Can I drive my vehicle with OBDII code C1781?

It is not recommended to drive your vehicle with OBDII code C1781 as it can lead to potential safety hazards due to the compromised steering angle sensor circuit.

5. What are the repair options for OBDII code C1781?

Repair options for OBDII code C1781 include replacing the faulty steering angle sensor, repairing any damaged wiring or connectors, or reprogramming the ECU if necessary.

6. How much does it cost to fix OBDII code C1781?

The cost to fix OBDII code C1781 can vary depending on the specific cause of the issue, but it may range from a few hundred to a few thousand dollars, including parts and labor.

7. Can OBDII code C1781 be triggered by a dead battery?

Yes, in some cases, a dead or low battery voltage can trigger OBDII code C1781 due to disruptions in the electrical system affecting the steering angle sensor circuit.

8. Is it possible to reset OBDII code C1781 without repairs?

Resetting OBDII code C1781 without addressing the underlying issue will only temporarily clear the code. The problem will persist and may lead to safety concerns if left unresolved.

9. Will OBDII code C1781 cause my vehicle to fail an emissions test?

OBDII code C1781 is related to the steering angle sensor circuit and may not directly cause your vehicle to fail an emissions test. However, it should still be addressed to ensure overall vehicle safety.

10. How can I prevent OBDII code C1781 from recurring in the future?

To prevent OBDII code C1781 from recurring, you should perform regular maintenance checks on your vehicle, including inspecting the steering angle sensor and related components for any signs of wear or damage.