What is OBD-II Code P079C – Transmission Friction Element C Slip Detected

What is OBD-II Code P079C – Transmission Friction Element C Slip Detected

OBD-II (On-Board Diagnostics II) is a system found in all vehicles from 1996 onwards that continuously monitors the performance and health of the vehicle’s systems. It uses a series of sensors and codes to identify any issues or malfunctions in the system, which are then communicated through a diagnostic trouble code (DTC), such as OBD-II Code P079C – Transmission Friction Element C Slip Detected.

When your vehicle’s OBD-II system detects an issue, a code is generated that can be read by a scanner. These codes can be anything from minor issues to major problems that require immediate attention. In this article, we will be discussing OBD-II Code P079C – Transmission Friction Element C Slip Detected, what it means, and how to repair the issue.

What is OBD-II Code P079C – Transmission Friction Element C Slip Detected?

OBD-II Code P079C refers to a problem with the transmission system in your vehicle. Specifically, it means that the ECU (Engine Control Unit) has detected a malfunction in the transmission’s Friction Element C, which is causing it to slip. This slip can be caused by a variety of issues, including low transmission fluid levels, worn-out transmission components, or faulty sensors.

What are the Symptoms of OBD-II Code P079C?

When your vehicle’s OBD-II system detects an issue, it may illuminate the Check Engine Light (CEL) on the dashboard. In the case of OBD-II Code P079C, there are typically several other symptoms that you may notice as well. These symptoms can include:

1. Harsh or delayed shifting
2. Poor acceleration or lack of power
3. Transmission slipping or jerking
4. Overheating of the transmission
5. Decreased fuel efficiency

If you notice any of these symptoms, it is best to have your vehicle inspected by a professional mechanic to prevent further damage or issues with your vehicle.

What Causes OBD-II Code P079C?

Several issues could cause OBD-II Code P079C to appear, including:

1. Low Transmission Fluid: Low transmission fluid levels can cause components to wear out or fail prematurely, leading to transmission slipping and failure.
2. Malfunctioning Friction Element C: Friction Element C is designed to engage and disengage to create and control torque between specific parts of the transmission, and when it fails, it causes the transmission to slip.
3. Faulty Sensors: Faulty sensors provide inaccurate data to the transmission’s control module, leading to incorrect readings and subsequent problems.
4. Worn-Out Components: Over time, transmission components such as clutches, gears, and bearings can wear out or become damaged, causing slipping.

How to Repair OBD-II Code P079C?

The repair for P079C largely depends on the cause of the issue. Here are a few ways to repair this condition:

1. Check and refill transmission fluid: Low fluid levels can cause slipping; therefore, check the fluid level and refill as necessary.
2. Replace Friction Element C: If the Friction Element C has failed, it must be replaced.
3. Clean or replace sensors: Faulty sensors may need to be cleaned or replaced to provide accurate data to the transmission’s control module.
4. Replace transmission components: If the issue is due to worn-out components, you must replace these parts. Your mechanic will need to disassemble your transmission to determine which parts are worn or damaged.


1. What happens if I don’t repair OBD-II Code P079C – Transmission Friction Element C Slip Detected?

A. If left unaddressed, OBD-II Code P079C can cause severe damage to the transmission and engine, leading to unsafe driving conditions and costly repairs.

2. Can I fix the issue myself?

A. While replacing the transmission fluid is a task most people can do themselves, diagnosing the underlying cause of the issue is best left to professional mechanics. Attempting to fix the issue yourself could lead to additional problems and further component failure.

3. How can I prevent OBD-II Code P079C from occurring?

A. Regular maintenance of your vehicle, including fluid and filter changes, can prevent issues like this. Additionally, do not tow more than the vehicle’s recommended towing capacity.

4. How much does it cost to repair OBD-II Code P079C?

A. The cost of repair depends on the severity of the issue and the parts needing replacement. The average cost of repair can range from $400 to $1500 and up, depending on the cause of the problem.

5. Is OBD-II Code P079C common in only certain types of vehicles?

A. OBD-II Code P079C can appear in any vehicle with an automatic transmission system, regardless of the make, model, or year.


OBD-II Code P079C – Transmission Friction Element C Slip Detected can be a serious issue that requires immediate attention. We have discussed the symptoms, causes, and repair options available to address this issue. Regular maintenance and inspections of your vehicle can help prevent this and other issues from arising in the future. If you suspect that your vehicle has OBD-II Code P079C, it is best to take it to a mechanic who has the necessary experience and knowledge to diagnose and repair the issue properly.

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