Electric/Auxiliary Transmission Fluid Pump Motor Phase V Current Low
What it means
The electric/auxiliary transmission fluid pump motor phase V current is low. This pump moves transmission fluid when the engine is off or at low speed, such as for stop/start, so shifting can suffer if it fails.
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
- Transmission slipping or hesitation
- Delayed or erratic shifting
- Overheating of the transmission
- Illumination of the check engine light
- Loss of power during acceleration
Common causes
Most likely first
- Faulty electric/auxiliary transmission fluid pump motor
- Malfunctioning transmission control module
- Low or contaminated transmission fluid
- Wiring or connection issues with the electric/auxiliary transmission fluid pump motor
- Defective sensors related to the transmission system
How to diagnose & fix
Work through it in order
- Check and replace any faulty wiring or connectors related to the electric/auxiliary transmission fluid pump motor phase V current.
- Inspect and replace the electric/auxiliary transmission fluid pump motor if it is found to be defective.
- Verify and correct any issues with the power supply to the electric/auxiliary transmission fluid pump motor phase V current.
- Ensure that the control module responsible for regulating the electric/auxiliary transmission fluid pump motor phase V current is functioning correctly and replace if necessary.
Related codes
Read & clear P0B04 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
Need a scanner that reads ABS, airbag and more? GaragePro OBD scan tools ship worldwide. See scanners →