What it means
Generator phase U current is below the expected range. The code identifies a low-current condition but does not establish its cause.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The hybrid control module monitors current in generator phase U as the inverter manages generator output. This code sets when the measured phase U current is lower than expected; a partially open phase winding or a current-sensor offset can produce that result.
Common causes
Most likely first.
- Phase winding partially open
- Current sensor offset drifted
Symptoms
- Check-engine or hybrid-system warning light
- Reduced hybrid performance
- Possible reduced-power mode
How to diagnose it
- Save freeze-frame data and compare live generator phase U current with phases V and W under the conditions recorded when the code set.
- Check for other generator or inverter codes and note whether phase U reads consistently low or changes intermittently.
- With high-voltage safety procedures followed, inspect phase U wiring and generator and inverter connectors for corrosion, loose terminals, or heat damage.
- Test the phase U current-sensor signal and wiring for an open, poor connection, or offset using the manufacturer's diagnostic information.
- If the sensor circuit is sound, have the generator phase U winding checked for partial opens and compared with the manufacturer's specification.
Common fixes
- Clean and secure a poor phase U connector or repair damaged wiring.
- Repair an open or high-resistance section in the generator phase U circuit.
- Replace the phase U current sensor if testing confirms its reading has drifted.
- Repair or replace the generator if a partial phase U winding open is confirmed.
Can I keep driving?
Avoid demanding acceleration or towing, since reduced hybrid output or reduced-power mode may occur. Arrange prompt diagnosis; stop if propulsion becomes unreliable or the vehicle displays a stop warning.
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.