What it means
The auxiliary transmission fluid pump control module feedback signal is lower than expected.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The auxiliary transmission pump control module sends a feedback signal that the vehicle's control system uses to monitor pump operation. This code sets when that signal falls below the expected level. A short to ground, an open or poor connection, or a faulty module can pull the feedback low.
Common causes
Most likely first.
- Short to ground or open circuit in feedback wiring
- Poor connector connection
- Faulty pump control module
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 live feedback to confirm the signal is low when the pump module is operating or being commanded.
- Inspect the feedback wire and module connector for corrosion, loose terminals, chafing, or contact with ground.
- Using the manufacturer's wiring information, test the feedback circuit for an open or short to ground.
- If supported, command the pump and observe whether the feedback remains low or changes with operation.
- Check module power and ground connections using the manufacturer's procedure.
- If the circuit and its connections pass, test the pump control module for a failed feedback output.
Common fixes
- Repair a short to ground or open in the feedback wiring.
- Clean, secure, or replace damaged feedback connector terminals.
- Repair a faulty module power or ground connection.
- Replace the pump control module if its feedback output remains low with a sound circuit.
Can I keep driving?
Avoid driving if transmission shifts are delayed, harsh, or slipping, or if limp mode is active; the low feedback signal can leave pump operation unverified. If the vehicle behaves normally, limit driving and arrange diagnosis soon.
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.