What it means
Pressure control solenoid M is commanded on but does not produce the expected pressure. Spool stuck closed or hydraulic feed restricted.
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 controls hydraulic pressure in a transmission circuit when the TCM commands it on. This performance or stuck-off fault sets when the command is present but the expected pressure response does not occur, which can point to a closed or sticking spool or a restricted hydraulic feed.
Common causes
Most likely first.
- Solenoid spool stuck in closed position
- Hydraulic feed restricted by debris
- 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
- Save freeze-frame data and compare solenoid M's commanded state with available pressure and shift data to confirm the fault occurs when it is commanded on.
- Check transmission fluid level and condition using the specified procedure, since low or contaminated fluid can restrict or weaken the pressure response.
- Inspect the solenoid M connector and nearby harness for damage, corrosion, or loose pins that could prevent the command from reaching the solenoid.
- Run a supported scan-tool actuator test for solenoid M and observe whether the expected pressure or shift change follows the command.
- If electrical checks pass, inspect the hydraulic feed and solenoid M spool for debris or sticking, following the manufacturer's service procedure.
Common fixes
- Correct the fluid level or service contaminated fluid and filter as specified.
- Repair the solenoid M connector or wiring if inspection finds a poor connection or damage.
- Clean or clear a restricted hydraulic feed if the approved service procedure allows it.
- Replace a solenoid M that sticks closed or fails its commanded test.
- Repair the valve body if debris or bore wear continues to restrict solenoid M's hydraulic flow.
Can I keep driving?
Limit driving and avoid towing or demanding acceleration if the transmission shifts harshly, slips, or enters limp mode. A pressure circuit that fails to respond can lead to loss of drive or further internal transmission 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.