What it means
The current sensor for starter/generator phase Y 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’s phase Y current sensor measures current in phase Y for control of electrical assist and charging. This code sets when an electrical fault in the phase Y sensor circuit makes that phase’s current 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 Y current data to identify the conditions present when the fault set.
- With the vehicle safely powered down according to the manufacturer's procedure, inspect the phase Y sensor connector and harness for looseness, corrosion, abrasion, or heat damage.
- Check phase Y sensor wiring and terminals for opens, shorts, or poor connections using the manufacturer's specification.
- Inspect accessible sensor grounds and power feeds for damage or loose connections.
- Compare phase Y current readings with phases X and Z under comparable operating conditions to look for a phase-specific discrepancy.
- Test the phase Y sensor and circuit as specified by the manufacturer, replacing the sensor only after wiring and connections are verified.
Common fixes
- Reconnect a loose phase Y current-sensor connector.
- Repair damaged phase Y sensor wiring or terminals.
- Restore a faulty sensor ground or supply connection.
- Replace the phase Y current sensor if the circuit checks out but the sensor output remains faulty.
Can I keep driving?
The vehicle may have reduced starter/generator assist or charging and may start less smoothly. Limit driving until the fault is diagnosed, and stop safely if starting becomes unreliable or a hybrid-system warning worsens.
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.