What it means
Electric/auxiliary transmission fluid pump B is producing pressure below the expected level.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Electric or auxiliary transmission fluid pump B supplies hydraulic pressure for the transmission when commanded. The module monitors pressure associated with pump B and sets P27E2 when it falls below the expected level; low fluid or internal pump wear or leakage can reduce that pressure.
Common causes
Most likely first.
- Pump worn or leaking internally
- Transmission fluid level low
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 review live transmission data for pump B operation and pressure at the time of the fault, checking for related pump A or pressure codes.
- Check the transmission fluid level and condition according to the manufacturer's procedure because low fluid can starve pump B.
- Inspect the transmission and pump B area for leaks that could lower fluid level or pressure.
- Use a scan tool to observe or command pump B and compare its pressure data with the manufacturer's expected values.
- If fluid level and leaks do not explain the low reading, test pump B and its hydraulic circuit for internal wear or leakage using the manufacturer's procedure.
Common fixes
- Correct the fluid level using the specified fluid and procedure.
- Repair any leak that is lowering transmission fluid level or pressure.
- Replace pump B if testing confirms internal wear or leakage.
- Repair an internally leaking passage or seal if hydraulic testing identifies it.
Can I keep driving?
Avoid driving if the transmission slips, misses shifts, or enters limp mode, because low pump B pressure can damage internal transmission parts. Have it diagnosed promptly, and stop if the vehicle loses drive or cannot shift safely.
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.