What it means
The control circuit for pressure control solenoid T is not performing within the expected range.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Pressure control solenoid T is an electrically operated valve that helps regulate transmission hydraulic pressure. The transmission control module compares the solenoid T circuit response with its expected range and sets P27DE when electrical performance falls outside that range, even if the circuit is not fully open or shorted.
Common causes
Most likely first.
- Solenoid coil resistance out of specification
- High-resistance connection in solenoid wiring or connector
- Fault in the control circuit
Symptoms
- Transmission warning light may illuminate
- Harsh or delayed shifting
- Slipping or unexpected shifts
- Transmission may enter limp mode
How to diagnose it
- Record freeze-frame data and transmission live data with a scan tool, noting when P27DE appears and whether commanded solenoid T operation matches the reported response.
- Inspect the solenoid T connector and wiring for corrosion, loose terminals, chafing, or damage that could add resistance.
- Check the solenoid T coil resistance and compare it with the manufacturer's specification.
- Test the solenoid T wiring and connector for excessive resistance or poor continuity using the manufacturer's procedure.
- If the solenoid and harness pass, test the control circuit and TCM output as directed by the manufacturer.
Common fixes
- Clean and secure a poor solenoid T connector contact, or repair a damaged terminal.
- Repair high-resistance or damaged wiring in the solenoid T control circuit.
- Replace pressure control solenoid T if its coil is outside the manufacturer's specification.
- Repair the control circuit or TCM driver if tests identify a fault there.
Can I keep driving?
Limit driving and avoid towing or hard acceleration because pressure control problems can cause slipping, harsh shifts, or limp mode. Stop if the transmission slips or loses drive, as continued operation can increase internal damage.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.