What it means
The control module monitors the hydraulic pump command and feedback for an operating state that indicates the pump is on. It sets this code when the pump remains on when the system expects it to be off.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The hydraulic pump supplies pressure for transmission operation, and the control module compares its command with feedback about whether the pump is running. P094B sets when the module expects the pump to be off but detects that it remains on, which can happen if the relay contacts are welded or the pump driver stays energized.
Common causes
Most likely first.
- Pump relay contacts welded
- 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
- Record freeze-frame data and check transmission live data for the pump command and reported state to confirm the pump is being detected as on when commanded off.
- Inspect the pump relay, fuse area, connectors, and wiring for heat damage, corrosion, loose terminals, or signs that the relay has stuck closed.
- With the vehicle’s service information, compare pump command and feedback during conditions when the pump should switch off.
- Test whether the relay contacts continue to supply power when the control module is no longer commanding the pump.
- If the relay and wiring pass, have the pump driver and pump mechanism checked for a stuck-on condition or debris that prevents free movement.
Common fixes
- Repair a loose, damaged, or corroded pump connector or wire.
- Replace a relay with welded contacts.
- Repair a faulty pump driver circuit.
- Clean or replace a pump that is mechanically sticking, as appropriate for the vehicle.
Can I keep driving?
Limit driving and avoid towing or hard acceleration; a pump that stays on can overheat or impair transmission operation. If shifts become harsh, slip, or the vehicle enters limp mode, stop somewhere safe and arrange recovery.
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.