What it means
The current sensor for starter/generator phase X reports a circuit fault. Phase current measurement is unreliable.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The starter/generator uses three electrical phases, and a current sensor measures the current in phase X so the control module can manage assist and charging. This code sets when the phase X sensor circuit has an electrical fault that makes its reading unreliable.
Common causes
Most likely first.
- Current sensor failed
- Wiring fault
Symptoms
- Check-engine or hybrid-system warning light
- Reduced starter/generator assist or charging
- Rough or reduced engine starting assistance
How to diagnose it
- Scan for related hybrid or charging codes and review freeze-frame and live phase X current data to see when the circuit fault occurred.
- With the vehicle safely powered down according to the manufacturer's procedure, inspect the phase X sensor connector and nearby harness for looseness, corrosion, abrasion, or heat damage.
- Check the sensor wiring and terminals for opens, shorts, or poor connections, comparing the circuit with the manufacturer's specification.
- Inspect accessible grounds and power feeds used by the sensor circuit for looseness or damage.
- Compare phase X current-sensor data with phases Y and Z under comparable operating conditions to identify an isolated phase X reading.
- Test the phase X sensor and its circuit as specified by the manufacturer, then replace the sensor only if wiring and connections test correctly.
Common fixes
- Reconnect a loose phase X current-sensor connector.
- Repair damaged phase X sensor wiring or terminals.
- Restore a faulty sensor ground or supply connection.
- Replace the phase X current sensor if its circuit is sound but its output remains faulty.
Can I keep driving?
Because the vehicle may reduce starter/generator assist or charging and enter a limited operating mode, avoid long trips and watch for worsening starting or charging behavior. If the engine will not start reliably or a hybrid-system warning escalates, stop in a safe place and arrange service.
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.