What it means
Pressure control solenoid B does not release line pressure when commanded — output pressure remains at maximum, leading to harsh shifts and elevated stress on the clutch packs and seals.
At a glance
- Usually lights the check-engine light
How it works
Pressure control solenoid B controls hydraulic pressure in the transmission under TCM command. This code indicates that pressure remains high when the solenoid is commanded to release it, often because debris or contamination is preventing the valve from moving freely.
Common causes
Most likely first.
- Solenoid stuck open by debris
- Contaminated ATF clogging the pressure control valve
- 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
- Read freeze-frame data and transmission codes to confirm when solenoid B was commanded to reduce pressure and what shift behavior accompanied the fault.
- Check the transmission fluid level and condition using the manufacturer's procedure, looking for contamination that could obstruct the pressure-control valve.
- Inspect the transmission case connector and harness for damage or poor contact that could keep the solenoid energized.
- Use available live data to compare the solenoid B command with pressure or shift response and confirm that pressure is not releasing as expected.
- Test solenoid B electrical operation and commanded movement according to the manufacturer's procedure.
- If the electrical test passes, inspect the valve body and regulator passages for debris, carbon, or a sticking valve.
Common fixes
- Repair any damaged wiring or connector fault that is holding solenoid B in the wrong state.
- Service contaminated transmission fluid and replace the filter as specified by the manufacturer.
- Clean or repair the valve body and pressure-control passage if debris is restricting movement.
- Replace pressure control solenoid B if it sticks or fails its test.
Can I keep driving?
Avoid driving if shifts are severely harsh, the transmission slips, or warning signs worsen; arrange prompt diagnosis because sustained high line pressure can stress clutch packs and seals. If the vehicle remains controllable, drive gently only as far as needed to reach a safe place for service.
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.