P27AA: Pressure Control Solenoid D Data Incompatible

What it means

The calibration data programmed for pressure control solenoid D does not match the format expected by the transmission controller.

At a glance

• Usually lights the check-engine light

How it works

Pressure control solenoid D regulates transmission hydraulic pressure under the TCM's control. This code sets when the calibration data for solenoid D is in a format or version the TCM does not accept, which can interfere with commanded pressure control.

Common causes

Most likely first.

1. Replacement solenoid incompatible with software version
2. Calibration code format does not match controller version

Symptoms

• Check engine or transmission warning light may be on
• Harsh, delayed, or erratic shifting
• Transmission may enter a limited operating mode

How to diagnose it

1. Capture freeze-frame data and check other transmission codes, noting whether the fault appeared after solenoid D replacement or TCM programming.
2. Verify that pressure control solenoid D is compatible with the transmission and TCM software version.
3. Read solenoid D's calibration data and compare its format with the controller's specified requirements.
4. Check that the correct calibration for solenoid D was entered during installation or programming.
5. If the data and solenoid are compatible, consult vehicle-specific service information for any required TCM software update or calibration.

Common fixes

• Program the correct calibration data for pressure control solenoid D.
• Replace an incompatible solenoid D with a compatible unit.
• Correct the calibration format or entry associated with solenoid D.
• Update or reprogram the TCM if vehicle-specific service information calls for it.

Can I keep driving?

Limit driving if the transmission shifts harshly, late, or erratically, or enters a limited mode, because incorrect pressure control may increase transmission wear. Stop driving if the vehicle cannot shift predictably.