What it means
The controller detects a low electrical condition in the auxiliary transmission fluid pump control circuit.
At a glance
- Usually lights the check-engine light
How it works
The auxiliary transmission fluid pump is powered through a control circuit monitored by the transmission controller. This code sets when the controller detects the circuit voltage or current below the expected range, such as when the control wire is grounded, the motor winding is shorted, or corrosion raises resistance at a connector.
Common causes
Most likely first.
- Control wire shorted to ground
- Motor winding short
- Connector pins corroded - high contact resistance
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 pump command, circuit readings, and related transmission codes to identify when the low condition occurred.
- Inspect the auxiliary pump connector and harness for corrosion, moisture, pin damage, chafing, or a wire contacting ground.
- With the circuit isolated as directed by the manufacturer's procedure, check for a short to ground in the pump control wire.
- Test voltage drop and continuity across the connector and control circuit while the pump is commanded, comparing results with the manufacturer's specification.
- If wiring and connections pass, test the pump motor winding for a short using the manufacturer's procedure.
Common fixes
- Clean and secure corroded or loose pump connector terminals, replacing damaged terminals as needed.
- Repair a control wire shorted to ground.
- Replace a pump with a shorted motor winding.
- Clear the code and confirm the circuit responds correctly during a commanded pump test.
Can I keep driving?
Avoid towing or demanding driving if shifting is delayed, slipping, or harsh, because a low pump circuit can leave the transmission without the pressure it needs. Stop if the vehicle loses drive or shifts into limp mode.
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.