Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit Low
What it means
The electric/auxiliary transmission fluid pump A motor supply voltage circuit reads low. The pump moves transmission fluid when the engine is off or at low speed, so shifting can suffer if it loses power.
Can I keep driving? Shifting may be rough or the car may drop into a limited gear; drive gently, avoid towing, and get it read soon.
What this part does
The auxiliary electric transmission fluid pump supplies transmission fluid pressure when the engine is stopped, such as during an engine start-stop event or while a hybrid runs on electric power. The transmission control module switches it on so clutches stay filled and shifts stay smooth. Some designs work with high voltage, where service is for trained people. A fault can cause delayed engagement or rough starts from rest.
Common symptoms
What you'll notice
- Erratic shifting or slipping of gears
- Delayed or harsh shifting of gears
- Illuminated check engine light
- Stalling or hesitation during acceleration
- Loss of power or reduced performance
Common causes
Most likely first
- Loose or corroded electrical connections in the auxiliary/transmission fluid pump
- Faulty auxiliary/transmission fluid pump motor
- Blown fuse in the motor supply voltage circuit
- Damaged or faulty wiring in the motor supply voltage circuit
- Malfunctioning control module regulating the motor supply voltage
How to diagnose & fix
Work through it in order
- Check the wiring and connections of the electric/auxiliary transmission fluid pump.
- Test the motor supply voltage circuit for any open circuits.
- Inspect the fuse related to the electric/auxiliary transmission fluid pump and replace if necessary.
- Verify that the motor supply voltage is reaching the electric/auxiliary transmission fluid pump.
- Replace the electric/auxiliary transmission fluid pump if all other solutions fail.
Related codes
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