Electric/Auxiliary Transmission Fluid Pump Motor Phase W Current High
What it means
The electric/auxiliary transmission fluid pump motor phase W current is high. 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
- Delayed or hesitant gear shifting
- Inability to shift gears or engage certain gears
- Transmission slipping or jerking
- Overheating of the transmission
- Complete loss of power to the transmission
Common causes
Most likely first
- Faulty electric/auxiliary transmission fluid pump motor
- Low voltage in the wiring/connectors related to the pump motor
- Defective transmission fluid pump motor phase W current sensor
- Defect in the control module or relay for the pump motor
- Disruption in the power supply to the pump motor phase W
How to diagnose & fix
Work through it in order
- Check the wiring and connections to the electric/auxiliary transmission fluid pump motor.
- Inspect the motor for any signs of damage or malfunction.
- Test the motor's current to determine if it is operating below the recommended levels.
- Replace the electric/auxiliary transmission fluid pump motor if necessary.
- Consult the vehicle manual for any specific troubleshooting steps or recommendations.
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