Fault code P2788 is called “Auto Shift Manual 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 P2788
This diagnostic trouble code (DTC) is a generic transmission code. Error P2788 is considered a generic code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.
This code applies to vehicles with automatic transmission. It is set when adaptation cannot be performed due to limit values. Normally, the limit values relate to clutch wear, which is why no adaptation can be performed.
Adaptation of the automatic transmission (AMT) is necessary for proper operation of the clutch release actuator. If this is not done, transmission malfunctions can occur. Such as jerks, jerks during driving, as well as increased clutch wear.
Adaptation is usually required after repairs, such as after replacing the clutch. In some cases, adaptation is performed as the clutch is worn to improve performance.
This means that the automatic transmission must be re-trained whenever it is serviced or repaired. If the re-training procedure cannot be performed due to limit values, code P2788 will be stored.
Symptoms of vehicle malfunctions
The main signal that an error P2788 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 stored as a fault).
- The transmission does not shift properly.
- Jerking when shifting or driving.
- There may be no symptoms other than a stored fault code.
A stored fault code P2788 is considered serious, as it can cause driving and safety problems. The conditions that have contributed to the stored code must be corrected as soon as possible.
Factors that can cause this error code
The error code P2788 can mean that one or more of the following problems have occurred:
- Transmission has not been adapted.
- Calibration has not been performed correctly.
- Short-circuited or damaged wiring harness in gear shift circuit.
- Faulty wiring harness connector.
- Transmission control module (TCM) may be defective.
How to fix or reset OBD-2 code P2788
Some suggested steps for troubleshooting and fix the error code P2788:
- Read all stored data and error codes with an OBD-II scan tool.
- Clear the error codes from the computer memory.
- Test-drive the vehicle to see if error P2788 appears again.
- Perform transmission adaptation according to the manufacturer’s technical documentation.
- Visually inspect the relevant wires and connectors for damage.
- If necessary, replace the defective parts.
- Test the transmission control module (TCM).
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 P2788 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 at least 12 volts and that the alternator is running properly, at least 13 volts at idle.
The transmission control module (TCM) fails very rarely, but it can happen. Therefore, when diagnosing error P2788, it should be checked if all other steps have been completed.
On which vehicles does this problem occur most frequently
Fault code P2788 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- BMW
- Honda (Fit, Vezel)
Fault code P2788 can sometimes be found with other errors. The most common are the following: P0949, P0950, P0951, P0952, P0953, P0954.
