What it means
The transmission control module detects an intermittent fault associated with pressure control solenoid T.
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. P27DC sets when the transmission control module detects an electrical fault that comes and goes, often as a connector contact changes with vibration or the coil behaves differently as it warms.
Common causes
Most likely first.
- Solenoid connector not fully seated
- Coil resistance drifts with temperature
- Connector with intermittent contact under vibration
Symptoms
- Transmission warning light may illuminate
- Intermittent harsh or delayed shifting
- Transmission may intermittently enter limp mode
How to diagnose it
- Record freeze-frame data and review when P27DC sets, including transmission temperature and operating conditions.
- Inspect and reseat the solenoid T connector, checking for loose locking tabs, corroded terminals, or pins that move in the connector body.
- Examine the solenoid T harness for chafing or damage, and gently move the harness while monitoring live circuit data for dropouts.
- Measure solenoid T coil resistance when cold and after it warms, comparing readings with the manufacturer's specification.
- If the connector, harness, and coil remain stable, test the TCM control circuit for intermittent faults using the manufacturer's procedure.
Common fixes
- Fully seat and secure the solenoid T connector or replace a damaged connector terminal.
- Repair chafed or intermittently open wiring in the solenoid T harness.
- Replace pressure control solenoid T if its coil resistance becomes unstable outside specification as it warms.
- Repair the TCM control circuit if testing confirms an intermittent fault there.
Can I keep driving?
Because shifting or limp mode can change suddenly, avoid long trips, towing, and hard acceleration until the intermittent fault is found. Stop if the transmission begins slipping or loses drive.
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.