P2788 code definition
This DTC represents Auto Shift Manual Adaptive Learning at Limit.
What the P2788 code means
Your vehicle adapts to your specific driving habits via adaptive transmission. This function is controlled by the PCM (powertrain control module) or TCM (transmission control module), using a variety of data obtained from sensors, actuators, and hydraulic pressure information. The purpose of the system is to improve torque application and devise an efficient shifting strategy according to the driving conditions.
When the computer detects an anomaly in the adaptive learning system of the transmission, P2788 will set. The degree by which the adaptive response must exceed the expected limitations varies by make and model. In general, code-setting parameters are based upon throttle position, engine speed, engine load, and vehicle speed calculations.
What causes the P2788 code?
A problem with the automatic shifting manual adaptive learning system may be caused by:
- Clogged transmission fluid passages
- A bad electronic pressure control solenoid
- Internal mechanical transmission failure
- Contaminated or dirty transmission fluid
- Low transmission fluid
- A faulty TCM
- A faulty PCM (rare)
What are the symptoms of the P2788 code?
There may be a range of signs from no noticeable symptoms at all, all the way to completely disabled shifting function. Other possible problems include stalling at idle, harsh shifting, transmission overheating or slipping, and decreased fuel economy. The MIL (malfunction indicator lamp) may illuminate, and the code will store. There may also be other torque converter clutch, shift solenoid, gear ratio, or transmission slippage codes present.
How does a mechanic diagnose the P2788 code?
Diagnosis may involve:
- Verifying the codes present by using a code reader, and capturing the freeze frame data
- Clearing any fault codes out of the vehicle’s computer, road testing the vehicle, then checking to see if they return
- Inspecting the transmission fluid level and condition
- Inspecting the system wiring and connectors for corrosion, shorts, or loose connections
- Checking resistance and voltage at the pressure control solenoid, shift solenoids, torque converter lockup solenoids, and transmission temperature sensor
- Using an ohmmeter to check the system for continuity
- Using a manual pressure gauge to measure the transmission pump pressure
Common mistakes when diagnosing the P2788 code
Sometimes the transmission is rebuilt/replaced without checking all associated solenoids, wiring, and connections. This is a very expensive error to make, so be sure your technician is carrying out a thorough diagnostic process.
How serious is the P2788 code?
You should generally regard any transmission code as serious. Even if the problem is simply faulty wiring or a solenoid, this may lead to the transmission not functioning properly, which can eventually cause severe damage within the mechanical components.
What repairs can fix the P2788 code?
Possible fixes for this DTC include:
- Repairing defective solenoids, sensors, or actuators
- Repairing any transmission fluid leaks
- Repairing shorted or damaged wiring and connectors
- Replacing the transmission pump
- Replacing the electronic pressure regulator
- Rebuilding or replacing the entire transmission
- Replacing the TCM
- Replacing the PCM
Additional comments for consideration regarding the P2788 code
One of the first steps in determining the severity of this issue is to check the transmission fluid. If it looks or smells burned or abnormal in any way, this is a sign that the transmission has run in a low fluid condition for at least some amount of time, and there is a chance it may already have experienced catastrophic internal damage.
Dealing with transmission diagnoses and repairs can be a major undertaking, particularly if there is damage to the transmission itself. When dealing with a code like P2788 it’s best to leave the dirty work to a professional. A qualified technician has the required tools and expertise to find the source of the problem and fix it.
Need help with a P2788 code?
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