What it means
The auxiliary transmission fluid pump control module detects a low signal from its internal temperature sensor circuit.
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 uses an internal temperature sensor to monitor its own temperature. This code sets when the sensor circuit signal is lower than the module expects, which can indicate a short to ground, a sensor fault, or a module problem.
Common causes
Most likely first.
- Short to ground in the sensor circuit
- Faulty internal temperature sensor
- 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 transmission live data for pump operation or temperature readings that could show when the fault occurs.
- Inspect the pump control module connector and nearby wiring for loose pins, corrosion, moisture, or damage that could pull the sensor signal low.
- With the circuit identified from the vehicle wiring information, check whether the sensor signal is shorted to ground.
- Check the internal temperature sensor circuit and sensor response using the manufacturer's diagnostic procedure.
- If wiring and sensor checks pass, test the pump control module and its power and ground connections before replacing it.
Common fixes
- Clean and secure a loose or corroded pump control module connector.
- Repair sensor wiring that is shorted to ground.
- Replace the faulty internal temperature sensor if serviceable separately.
- Replace the pump control module if its internal sensor circuit has failed.
Can I keep driving?
Avoid driving if shifts are harsh, delayed, slipping, or the transmission enters limp mode; continued use can worsen transmission damage or leave you without normal shifting. If shifting remains normal, limit driving and have the fault checked promptly.
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.