C1239 Code - Foreign Object Attached on Tip of Left Rear Sensor
Quick Answer
The speed sensor detects wheel speed and sends the appropriate signals to the ECU. Common causes include Faulty Left Rear Speed Sensor, Left Rear Speed Sensor rotor, Sensor installation. 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
- C1239 indicates Foreign Object Attached on Tip of Left Rear Sensor.
- Common causes
- Common causes include Faulty Left Rear Speed Sensor, Left Rear Speed Sensor rotor, Sensor installation.
- 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.
Code C1239 Description
When the rotors rotate, the magnetic field emitted by the permanent magnet in the speed sensor generates AC voltage. Since the frequency of this AC voltage changes in direct proportion to the speed of the rotor, the frequency is used by the ECU to detect the speed of each wheel.
What are the Possible Causes of the DTC C1239?
- Faulty Left Rear Speed Sensor
- Left Rear Speed Sensor rotor
- Sensor installation
- Faulty Skid Control ECU (Brake Actuator Assembly)
How to Fix the DTC C1239?
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 C1239 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 C1239 code?
Need more information on how to fix the C1239 code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the C1239 code diagnosed by a professional: Find a repair shop in your area
Information for Specific Makes
- C1239 Buick — Brake Pressure Sensor 1/2 Correlation
- C1239 Cadillac — Brake Pressure Sensor 1/2 Correlation
- C1239 Chevrolet — Brake Pressure Sensor 1/2 Correlation
- C1239 GMC — Brake Pressure Sensor 1/2 Correlation
- C1239 Lexus — Foreign Object Attached on Tip of Left Rear Sensor
- C1239 Scion — Foreign Object Attached on Tip of Left Rear Sensor
- C1239 Toyota — Foreign Object Attached on Tip of Left Rear Sensor
Frequently Asked Questions about C1239 Code
1. What does the OBDII code C1239 mean?
C1239 indicates that a foreign object is detected on the tip of the left rear sensor, potentially interfering with its proper function.
2. What are the common symptoms of code C1239?
Symptoms can include erratic readings from the left rear sensor, warning lights on the dashboard (e.g., ABS or traction control), or reduced functionality of driver-assist systems.
3. What causes OBDII code C1239 to appear?
The code is typically caused by debris, mud, ice, or a physical obstruction on the left rear sensor, or a damaged sensor tip.
4. How can I fix the C1239 code?
Inspect the left rear sensor for any debris or foreign objects and clean it carefully. If the sensor is damaged, it may need to be replaced.
5. Can I drive with the C1239 code active?
While the vehicle may still be drivable, safety systems like ABS or traction control may not function properly, so it's best to address the issue promptly.
6. How do I clean the left rear sensor to clear the C1239 code?
Gently wipe the sensor with a soft, damp cloth to remove dirt or debris. Avoid using abrasive materials that could damage the sensor.
7. Will clearing the C1239 code solve the problem?
Clearing the code without addressing the root cause may result in the code reappearing. Ensure the sensor is cleaned or repaired before resetting the code.
8. Can a damaged sensor wire cause the C1239 code?
Yes, a damaged or disconnected wire to the left rear sensor can sometimes trigger this code.
9. What tools are needed to diagnose the C1239 code?
A basic OBDII scanner can read the code, but a visual inspection of the sensor and its surroundings is also necessary.
10. Is the C1239 code specific to certain vehicles?
Yes, the code and its description may apply to specific vehicle makes and models, so refer to your vehicle’s service manual for exact details.
Discuss the causes and fixes for C1239 OBDII Code
Code C1239 comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
