P27AA: Pressure Control Solenoid D Data Incompatible
What to do
Drivable, and the answer is programming rather than parts. If this appeared after transmission work, go back to whoever did it — the solenoid characterisation step was missed or did not complete, and it is quick to put right with the proper tool. Shift quality may be poor in the meantime; the module is driving the solenoids through the wrong calibration, not failing mechanically.
What this code means
The characterisation data stored for pressure control solenoid D does not match the solenoid.
Modern pressure solenoids are individuals, and the module knows each one by name. Two solenoids off the same production line do not flow identically at the same current, and shift quality depends on pressure being exact. So manufacturers measure every solenoid's true current-to-pressure curve at the factory and record it — stored in the module, or printed on the solenoid as a code to be entered when it is fitted. The module then commands pressure through that solenoid's own curve.
Data incompatible means the curve on file does not belong to the solenoid in the gearbox. The wiring is intact and the solenoid may be healthy; what is wrong is the module's model of it. It almost always follows a repair: a solenoid, valve body or mechatronic unit changed without its characterisation being programmed in, a module swapped from another vehicle, or a programming session that did not run to completion.
The symptom is a gearbox that was just repaired and now shifts worse. Commanded through the wrong curve, every pressure is slightly off — harsh engagements, flare between gears, clunks the old unit never made. The fix is programming, not more parts: replacing the solenoid again without entering its data reproduces the fault with newer hardware.
Before valve body or mechatronic work, ask who will program the characterisation data. It is a five-minute step with the right tool and the difference between a repair that works and one that comes straight back.
Likely causes
Start here
- Incorrect module configuration after replacement · specialist
Less common
- Interrupted module programming · specialist
- Faulty transmission control module · specialist
Rare
- Faulty pressure control solenoid · specialist
Symptoms
Components involved
Information, not instruction
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Community experience
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