Fault code P278F is called “Clutch “B” Adaptive Learning at Limit” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P278F
OBD-II fault code P278F is a generic code that is defined as “Adaptive learning of clutch “B” at the limit”. It is set when the Transmission Control Module (TCM) detects that the “B” clutch can no longer be adapted.
On vehicles equipped with dual clutch transmissions, the computer reads data from several sensors. To create a specific shifting strategy to suit the owner’s driving style.
The clutch normally functions in positions between fully engaged (clutch closed) and fully disengaged (clutch open). If the TCM can no longer determine the appropriate shift strategy, this code is set.
The occurrence of the error may be due to an internal mechanical clutch fault, such as wear and tear. Or an electrical one, which may include, bad contacts or failure of the electronic unit.
Therefore, when the TCM can no longer detect a suitable shifting strategy, it sets code P278F, adaptive clutch “B” learning at the limit. Then the signal lamp lights up, which signals the occurrence of a problem.
Symptoms of vehicle malfunctions
The main signal that an error P278F has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be memorized as a fault).
- Other related fault codes may also be present.
- Poor transmission operation.
- Hard shifting of gears.
- Clutch or transmission slipping.
- Transmission overheating.
- Increased fuel consumption.
- The vehicle may enter failure or emergency operation mode.
The severity of fault code P278F is high, and transmission operation may be disrupted. Shifting problems may occur, creating a safety hazard.
Factors that can cause this error code
The error code P278F can mean that one or more of the following problems have occurred:
- Internal transmission failure.
- Clutch fraying.
- Mechanical failure of the transmission.
- Problem with wiring or connectors.
- Low or dirty transmission fluid.
- Faulty pressure control solenoid.
- Sometimes faulty TCM module is the cause.
How to fix or reset OBD-2 code P278F
Some suggested steps for troubleshooting and fix the error code P278F:
- Connect an OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
- Clear the error codes from the computer memory and test-drive the vehicle to see if code P278F appears again.
- Check the level and quality of the transmission fluid.
- Inspect the electrical wiring and connectors.
- Check the actuator and solenoid sensors.
- If the clutch is worn out, it must be replaced.
Diagnose and repair of problems
The first thing to do is to properly adapt the transmission as specified in the manufacturer’s technical documentation. In some cases, it is necessary to contact the dealer for this procedure.
Next, when diagnosing the P278F code, it is worth checking the electrical part for damage. In today’s vehicles, electrical and electronic signals require good cabling for proper data transmission.
Any faults, such as breaks, disconnected connectors or corrosion, can interrupt signals, leading to transmission control failures. Next, check the battery, as some PCM and TCM modules are sensitive to low voltage.
If the battery is low, the system may detect this as a failure. Make sure the battery is delivering a minimum of 12 volts and that the alternator is operating properly, a minimum of 13 volts at idle.
The transmission control module (TCM) fails very rarely, but it can happen. Therefore, when diagnosing error P278F, it should be checked if all other steps have been completed.
On which vehicles does this problem occur most frequently
Fault code P278F can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Ford (EcoSport, Focus)
Fault code P278F can sometimes be found with other errors. The most common are the following: P2789, P286F, P2872, P2877, P287A.
