What it means
A general fault in pressure control solenoid M. Detected via electrical resistance, response to commanded duty cycle, or downstream pressure measurement.
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 regulates hydraulic pressure in a transmission circuit under transmission control module (TCM) command. The TCM sets this general fault when its electrical checks, response to a duty-cycle command, or pressure feedback indicates that solenoid M is not behaving as expected; this code does not by itself identify whether the problem is electrical or hydraulic.
Common causes
Most likely first.
- Aged solenoid coil resistance drift
- Worn valve body bore around the solenoid
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
- Record all transmission codes and freeze-frame data, then compare solenoid M command and available pressure data with other shifts to see when the fault occurs.
- Check the transmission fluid level and condition using the vehicle's specified procedure, since low or contaminated fluid can affect the pressure response.
- Inspect solenoid M's connector and harness for loose pins, corrosion, fluid intrusion, or damage that could cause an electrical or intermittent fault.
- Use a scan tool's bidirectional test, if supported, to command solenoid M and observe the corresponding pressure or shift response.
- Measure solenoid M coil resistance and check its wiring against the manufacturer's specification, then investigate valve-body wear if electrical checks pass but pressure response remains abnormal.
Common fixes
- Repair a loose, damaged, or corroded solenoid M connector or harness connection.
- Replace pressure control solenoid M if its coil or commanded response fails the specified checks.
- Service the transmission fluid and filter if the fluid is contaminated or overdue under the vehicle's maintenance schedule.
- Repair or replace the valve body if wear around solenoid M prevents it from controlling pressure.
Can I keep driving?
Avoid towing, hard acceleration, and long trips if shifts are harsh, delayed, slipping, or the transmission enters limp mode. Continued driving with slipping or abnormal pressure can worsen clutch and 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.