What it means
Pressure control solenoid M stays in the activated state when commanded off. Affected hydraulic circuit stays pressurised.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Pressure control solenoid M switches hydraulic pressure in a transmission circuit according to TCM commands. This stuck-on fault sets when the circuit remains activated after the TCM commands solenoid M off, so pressure may stay applied when it should change or release.
Common causes
Most likely first.
- Solenoid spool stuck in open position
- TCM output driver stuck on
- Carbon or debris buildup preventing free movement
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Capture freeze-frame data and check solenoid M's commanded state alongside available pressure data to confirm pressure remains when the command is off.
- Check fluid level and condition using the vehicle's specified procedure, and note contamination that could make a valve stick.
- Inspect solenoid M's wiring and connector for shorts, corrosion, or damaged pins that could keep the solenoid electrically activated.
- Use a supported scan-tool actuator test to switch solenoid M on and off while observing the pressure or shift response.
- If wiring is sound, test the TCM output and inspect solenoid M and its valve-body passage for a spool stuck open or debris, following the manufacturer's procedure.
Common fixes
- Repair wiring or connector damage that is holding solenoid M's control circuit active.
- Clean or service contaminated fluid and the filter as specified.
- Replace solenoid M if its spool remains open or it does not release when commanded off.
- Repair the valve body if debris or bore wear prevents the solenoid valve from closing.
- Repair the TCM output driver only if testing confirms it continues to energize solenoid M with an off command.
Can I keep driving?
Avoid driving if the transmission is slipping, engaging unexpectedly, shifting harshly, or locked in limp mode; arrange prompt diagnosis. Continued operation with pressure applied at the wrong time can damage clutches and other transmission parts.
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.