What it means
The control module detects a fault related to current in phase W of the electric/auxiliary transmission fluid pump motor.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The electric or auxiliary transmission-fluid pump uses a three-phase motor to circulate fluid when the transmission needs hydraulic pressure. The control module monitors current in phase W and sets P0B06 when it detects a fault in that phase; the code does not by itself say whether current is too low or too high.
Common causes
Most likely first.
- Pump motor or phase wiring fault
- Pump motor control or current-sensing fault
Symptoms
- Transmission or hybrid system warning light
- Transmission operation may be limited
How to diagnose it
- Record freeze-frame data and scan for related transmission or hybrid codes to see when the phase W fault occurred and whether other pump faults are present.
- Use the scan tool’s available pump and phase-current data to check whether the fault is active and whether phase W differs from the other phases.
- With the system made safe according to the vehicle’s service information, inspect the pump connector and phase W wiring for damage, corrosion, loose terminals, or fluid intrusion.
- Check phase W wiring and connections for continuity, shorts, and excessive resistance using the manufacturer’s procedure and specification.
- If the wiring checks pass, have the pump motor and its control or current-sensing electronics tested to identify which is reporting the incorrect current.
Common fixes
- Repair damaged or loose phase W wiring and connector terminals.
- Clean and secure corroded or poorly seated pump connections.
- Replace the pump motor if testing confirms an internal phase fault.
- Repair or replace the pump control module or current-sensing circuit if testing identifies it as the cause.
Can I keep driving?
Because this fault can limit transmission operation, avoid long trips, heavy loads, and situations that require dependable acceleration. If shifting becomes abnormal or a hybrid/transmission warning appears, stop somewhere safe and arrange service; continued operation could worsen transmission damage.
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.