What it means
The power supply circuit B for the generator inverter reports a circuit low condition. Inverter operation may be impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The generator inverter uses supply circuit B to power its inverter electronics. The control module monitors the voltage on this supply and sets P2CC6 when it falls below the expected range, which can prevent the inverter from operating reliably.
Common causes
Most likely first.
- Supply wire shorted to ground
- Supply rail collapses under load
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Battery or charging system warning light
- Dim or flickering lights
- Difficulty starting or a discharged battery
How to diagnose it
- Review freeze-frame data and charging-system codes to see when circuit B voltage dropped and whether the fault occurred during load or startup.
- With the vehicle safely powered down as specified by the manufacturer, inspect circuit B wiring and connectors for damage, moisture, corrosion, or contact with ground.
- Check the circuit B supply and ground connections for excessive resistance or voltage drop, especially across corroded connector pins.
- Measure circuit B voltage at the inverter connector under the conditions described by the freeze-frame data and compare it with the manufacturer's specification.
- If the supply is low under load, isolate the wiring from the inverter and check for a short to ground; then test the supply rail and inverter as directed by vehicle-specific service information.
Common fixes
- Clean and secure corroded or loose circuit B connector pins.
- Repair damaged circuit B wiring that is shorted to ground.
- Repair a weak supply or ground connection causing voltage drop under load.
- Repair or replace the affected supply-rail or inverter component if circuit testing confirms it is faulty.
Can I keep driving?
Avoid relying on the vehicle for long trips if the charging warning is on, lights are flickering, or starting is difficult; the battery may discharge and the vehicle may lose power. If charging warnings or dimming worsen, stop somewhere safe and arrange prompt inspection.
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.