AutoCodes – Generic – C1236

C1236 Code - Left Rear Wheel Speed Sensor Input Signal Missing

Quick Answer

The ABS module receives wheel speed readings from each wheel speed sensor and processes this information to determine if an ABS event is necessary. Common causes include Faulty Left Rear Wheel Speed Sensor, Left Rear Wheel Speed Sensor harness is open or shorted, Left Rear Wheel Speed 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: C1236 indicates Left Rear Wheel Speed Sensor Input Signal Missing.
Common causes: Common causes include Faulty Left Rear Wheel Speed Sensor, Left Rear Wheel Speed Sensor harness is open or shorted, Left Rear Wheel Speed 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 42,891

How popular is this code, among other codes? Medium

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 Aug 28, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code C1236 Description

The ABS module receives wheel speed readings from each wheel speed sensor and processes this information to determine if an ABS event is necessary. The wheel speed sensor detects the magnetic field of the sensor ring as it passes the face of the active wheel speed sensor.

The active wheel speed sensor generates a signal that is sent to the ABS module. The wheel speed sensor circuitry connects to the ABS module through 2 wires and a connector at each wheel speed sensor. When the ignition is turned to the RUN position, the ABS module carries out a self-test by sending a reference voltage to all of the wheel speed sensors through their circuitry to determine if they are functional.

The ABS module continuously monitors and compares the rotational speed of each wheel and when it detects an impending wheel lock, modulates brake pressure to the appropriate brake caliper. This is accomplished by triggering the hydraulic control unit (HCU) to open and close the appropriate solenoid valves. Once the affected wheel returns to normal speed, the ABS module returns the solenoid valves to their normal position and normal (base) braking resumes.

OBDII Code C1236 - Left Rear Wheel Speed Sensor Input Signal Missing - AutoCodes.com — C1236 Code - Left Rear Wheel Speed Sensor Input Signal Missing

What does this mean?

What are the Possible Causes of the DTC C1236?

Faulty Left Rear Wheel Speed Sensor
Left Rear Wheel Speed Sensor harness is open or shorted
Left Rear Wheel Speed Sensor circuit poor electrical connection

How to Fix the DTC C1236?

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 C1236 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 C1236 code?

Need more information on how to fix the C1236 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C1236 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

C1236 Buick — Low System Supply Voltage
C1236 Cadillac — Low System Supply Voltage
C1236 Chevrolet — Low System Supply Voltage
C1236 Ford — Left Rear Wheel Speed Sensor Input Signal Missing
C1236 GMC — Low System Supply Voltage
C1236 Lexus — Foreign Object Attached on Tip of Left Front Sensor
C1236 Lincoln — Left Rear Wheel Speed Sensor Input Signal Missing
C1236 Mazda — Speed Wheel Left Rear Input Signal Missing
C1236 Mercury — Left Rear Wheel Speed Sensor Input Signal Missing
C1236 Pontiac — Low System Supply Voltage
C1236 Scion — Foreign Object Attached on Tip of Left Front Sensor
C1236 Toyota — Foreign Object Attached on Tip of Left Front Sensor

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 C1236 Code

1. What are the common symptoms of OBDII code C1236 (Left Rear Wheel Speed Sensor Input Signal Missing)?

Symptoms may include the ABS warning light illuminating on the dashboard, traction control issues, and potential loss of stability control.

2. What are the possible causes of OBDII code C1236?

Potential causes include a faulty left rear wheel speed sensor, damaged wiring or connectors related to the sensor, or issues with the ABS module.

3. How can I diagnose the cause of OBDII code C1236?

Diagnosis typically involves visually inspecting the left rear wheel speed sensor and its wiring, testing the sensor's output signal, and checking for any related ABS system faults.

4. Can a dirty or corroded sensor cause OBDII code C1236?

Yes, a dirty or corroded left rear wheel speed sensor can disrupt the signal and trigger the C1236 code. Cleaning or replacing the sensor may resolve the issue.

5. What is the recommended repair for OBDII code C1236?

The recommended repair typically involves replacing the left rear wheel speed sensor if it is found to be faulty, repairing any damaged wiring or connectors, and clearing the code from the system.

6. Is it safe to continue driving with OBDII code C1236 present?

It is not recommended to drive with the C1236 code active, as it may affect the proper functioning of the ABS and traction control systems, potentially compromising vehicle safety.

7. Can a DIY enthusiast fix OBDII code C1236 at home?

Depending on your skill level and access to tools, DIY enthusiasts may be able to address OBDII code C1236 by replacing the left rear wheel speed sensor and performing necessary repairs to the wiring.

8. Do I need a professional mechanic to reset OBDII code C1236 after repair?

A professional mechanic or automotive technician can clear the C1236 code from the system using a diagnostic scanner, ensuring that the repair was successful and the issue is resolved.

9. Are there any other codes related to OBDII code C1236?

Codes related to other wheel speed sensors or ABS system malfunctions may also be present alongside C1236, indicating potential broader issues with the ABS system.

10. How can I prevent OBDII code C1236 from recurring in the future?

Regularly inspecting and maintaining the wheel speed sensors, keeping connectors clean and secure, and addressing any ABS system warnings promptly can help prevent the recurrence of OBDII code C1236.