What it means
The auxiliary transmission fluid pump control module feedback signal is outside its expected range or does not behave as 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 reports feedback that lets the vehicle's control system check pump operation. The module compares that signal with the expected range and behavior as operating conditions change. This code sets when the feedback is present but outside the expected range or does not track correctly, pointing to a signal circuit or module problem.
Common causes
Most likely first.
- Feedback wiring or connector fault
- Faulty pump control module
- Faulty feedback circuit
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 compare live pump feedback with pump commands to see whether the signal is fixed, erratic, or out of range.
- Inspect the pump control module connector and feedback wiring for corrosion, loose terminals, chafing, or heat damage.
- Check the feedback circuit for excessive resistance, opens, or shorts using the manufacturer's wiring information and procedure.
- If supported by the scan tool, command pump operation and watch whether feedback changes smoothly and consistently with the command.
- Verify module power and ground under the conditions specified by the manufacturer.
- If the circuit and power supply test correctly but feedback still behaves abnormally, diagnose the control module.
Common fixes
- Repair damaged or corroded feedback wiring and connector terminals.
- Restore a sound module power or ground connection if testing finds a fault.
- Replace the pump control module if it produces out-of-range or erratic feedback despite a sound circuit.
- Clear the code and confirm feedback follows pump commands after the repair.
Can I keep driving?
Avoid driving if shifting becomes harsh, delayed, or unreliable, since abnormal feedback may cause the system to limit transmission operation. If there are no symptoms, keep trips short and arrange prompt diagnosis.
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.