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Engine-Codes – Toyota – C120C Toyota

C120C Toyota Code - Linear Solenoid Power Supply System Malfunction

Quick Answer

The C120C diagnostic trouble code (DTC) for Toyota vehicles refers to a Linear Solenoid Power Supply System Malfunction. Common causes include Faulty linear solenoid, Wiring or connector issues in the power supply system, Low transmission fluid levels or dirty transmission fluid. 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
C120C Toyota indicates Linear Solenoid Power Supply System Malfunction.
Common causes
Common causes include Faulty linear solenoid, Wiring or connector issues in the power supply system, Low transmission fluid levels or dirty transmission fluid.
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.
What is this?
Table of contents Created and updated by William Orellana on Aug 18, 2024
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Code C120C Toyota Description

The C120C diagnostic trouble code (DTC) for Toyota vehicles refers to a Linear Solenoid Power Supply System Malfunction. This code indicates that there is an issue with the power supply system for the linear solenoid, which is a crucial component in the vehicle's transmission system. The linear solenoid is responsible for controlling the hydraulic pressure within the transmission, allowing for smooth shifting between gears. When this system malfunctions, it can lead to a variety of transmission-related issues and affect the overall performance of the vehicle.

OBDII Code C120C Toyota - Linear Solenoid Power Supply System Malfunction
C120C Toyota Code - Linear Solenoid Power Supply System Malfunction

Common Causes of C120C Toyota

  1. Faulty linear solenoid
  2. Wiring or connector issues in the power supply system
  3. Low transmission fluid levels or dirty transmission fluid
  4. Electronic control module (ECM) malfunction
  5. Mechanical damage to the transmission components

Symptoms of C120C Toyota

  1. Rough or delayed shifting between gears
  2. Transmission slipping or jerking
  3. Illumination of the Check Engine Light
  4. Decreased fuel efficiency
  5. Transmission overheating

How to Fix C120C Toyota

  1. Diagnose the specific cause of the power supply system malfunction by using a scan tool to read the DTC and perform additional tests as needed.
  2. Inspect the wiring and connectors related to the linear solenoid for any signs of damage or corrosion.
  3. Check the transmission fluid level and condition, topping off or replacing as necessary.
  4. Test the linear solenoid itself for proper operation and replace if found to be faulty.
  5. Clear the DTC from the vehicle's memory, reset the transmission adaptations, and road test the vehicle to ensure proper operation.

Cost to Fix C120C Toyota

The cost of repairing a Linear Solenoid Power Supply System Malfunction can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. In general, the parts for this repair can range from $100 to $300, with labor costs adding an additional $100 to $200. Overall, the total repair cost for this issue could range from $200 to $500 or more. It's important to note that diagnostic time and labor rates can vary based on location and other factors, so it's recommended to get a quote from a trusted repair shop before proceeding with the repair.

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Information for Specific Toyota Models

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 C120C Toyota Code

1. What does the OBDII code C120C mean on a Toyota?

C120C indicates a "Linear Solenoid Power Supply System Malfunction," which relates to the vehicle's braking system, specifically an issue with the power supply to the solenoid controlling brake pressure.

2. What are common symptoms of the C120C code on a Toyota?

Symptoms may include the ABS warning light illuminating, reduced braking performance, or the vehicle's stability control system not functioning properly.

3. What causes the C120C code to appear in a Toyota?

Common causes include a faulty linear solenoid, damaged wiring or connectors in the power supply circuit, a blown fuse, or a malfunctioning ABS module.

4. Can I drive my Toyota with the C120C code active?

Driving with the C120C code may be unsafe as it can affect braking and stability systems. It is best to address the issue promptly to ensure safe operation.

5. How do I diagnose the C120C code on a Toyota?

Diagnosis involves checking the linear solenoid circuit, inspecting wiring and connectors for damage, testing the solenoid's resistance, and verifying that the ABS module is functioning correctly.

6. How is the C120C code repaired on a Toyota?

Repairs may include replacing the faulty linear solenoid, repairing or replacing damaged wiring or connectors, replacing a blown fuse, or, in some cases, replacing the ABS module.

7. What tools are needed to troubleshoot the C120C code on a Toyota?

You’ll need an OBDII scanner capable of reading ABS codes, a multimeter to test resistance and voltage, and basic tools for inspecting and repairing wiring or components.

8. How much does it cost to fix the C120C code on a Toyota?

Repair costs can vary depending on the exact cause but typically range from $100 to $500, with higher costs if the ABS module needs replacement.

9. Can a low battery cause the C120C code in a Toyota?

Yes, a weak or failing battery can cause voltage issues in the system, potentially triggering the C120C code. Ensure the battery is fully charged and in good condition.

10. Will clearing the C120C code fix the problem permanently?

No, clearing the code will only temporarily remove it from the system. The underlying issue must be diagnosed and repaired to prevent the code from returning.

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