What it means
The control system detects that auxiliary transmission fluid pump A is not turning when commanded.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Auxiliary transmission pump A supplies fluid pressure when commanded by the control system. The module checks for signs that the pump is turning after it switches the motor on. This code sets when pump A is commanded to operate but appears stalled, which may result from a seized motor, a mechanical blockage, or a failed electrical connection or driver.
Common causes
Most likely first.
- Pump motor seized or binding
- Pump mechanically obstructed
- Faulty pump driver or electrical connection
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 check live data to confirm whether pump A was commanded on and whether the module detected rotation or current.
- Inspect pump A and its connector and wiring for impact damage, corrosion, loose pins, or pinched or overheated wiring.
- Check transmission fluid level and condition using the manufacturer's procedure and look for signs of contamination that could obstruct the pump.
- If supported, command pump A with a scan tool and observe whether it runs or draws current.
- With power isolated according to the manufacturer's procedure, test the pump A circuit for opens or shorts and check whether the motor is mechanically bound.
- If the pump and circuit are serviceable, test the driver output to determine whether it supplies the commanded power.
Common fixes
- Repair a loose or damaged pump A connector or wiring.
- Correct fluid level or contamination issues according to the manufacturer's service procedure.
- Remove an obstruction or replace pump A if it is seized or mechanically binding.
- Repair or replace the pump driver if it fails the output test.
Can I keep driving?
Do not continue driving if shifts are missing, slipping, or the vehicle is in limp mode; a stalled auxiliary pump can leave the transmission without needed hydraulic pressure. Arrange prompt diagnosis, and stop safely if drive is lost or shifting becomes unpredictable.
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.