P27AC: Pressure Control Solenoid F Data Incompatible

What it means

The calibration data programmed for pressure control solenoid F 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 F helps regulate hydraulic pressure inside the transmission. The transmission controller relies on calibration data assigned to solenoid F and checks that the data format matches what its software expects. This code sets when the controller cannot use the stored or programmed solenoid F data in that format.

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. Use a scan tool to save transmission codes and freeze-frame data, noting whether the fault began after work involving solenoid F or the controller.
2. Check the installed solenoid F identification and calibration record against the vehicle's transmission and controller software version.
3. Inspect the solenoid F connector and transmission wiring for corrosion, fluid contamination, loose pins, or physical damage.
4. Use a transmission-capable scan tool to review solenoid F calibration status and check for related controller or communication faults.
5. Confirm the solenoid F calibration format is supported by the controller, then complete any required setup or programming by the manufacturer's procedure.

Common fixes

• Enter or correct the solenoid F calibration data using the format the controller expects.
• Clean and secure, or repair, the solenoid F connector and wiring as needed.
• Replace a solenoid F that is incompatible with the transmission or controller software.
• Reprogram the controller with a compatible manufacturer-approved software version if specified.

Can I keep driving?

Limit driving if shifts become harsh, delayed, or erratic, and avoid towing or heavy acceleration. If the transmission limits its available gears or shifts unpredictably, stop when safe and arrange recovery to reduce the risk of damage.