P2788Auto Shift Manual Adaptive Learning at Limit
- Generic OBD-II code · Powertrain
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2788 is the system-level code for an automated manual gearbox whose learned correction values have reached the end of their allowed range. Such units learn the clutch bite point, engagement speed and the end stops of the shift and select movements so that gear changes stay smooth as parts wear; when a value would have to move beyond its limit, the controller can no longer compensate and stores this code. No manufacturer documents P2788 publicly; it falls under the comprehensive component rules of CARB 13 CCR 1968.2. Allison's bulletins on the related P2789 show the usual route: check whether engine torque data are plausible and whether newer software exists before replacing parts. Also check clutch wear, actuator travel and whether a relearn was skipped after repair. P2789 and P278F are the clutch-specific versions.
- What you may notice
- Jerky take-off and harsh or slow shifts
- Transmission warning lamp
- Clutch slip or engine flare during shifts
- Likely causes
- LikelyWorn clutch moving the bite point beyond the learnable range
- PossibleBasic setting or relearn skipped after clutch, actuator or module work
- PossibleWorn or sticking shift and clutch actuators changing their travel
- RareOutdated software or implausible engine torque signal
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.