What it means
The hybrid control module detects a fault in the active discharge system used to safely drain the DC-link capacitors after shutdown. Discharge resistor or switch may have failed.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
After shutdown, the hybrid or EV discharge system uses a controlled path to drain stored energy from the DC-link capacitors in the inverter. P2D3B means the controller detects that this discharge process is not working as expected, commonly because the discharge resistor or its switching device has failed.
Common causes
Most likely first.
- Discharge resistor open
- Discharge switch failed
Symptoms
- Hybrid or EV system warning
- Vehicle may not start or enter Ready mode
- Reduced or unavailable electric drive
How to diagnose it
- Read freeze-frame data and related inverter or high-voltage codes to determine when discharge was commanded and whether the vehicle also failed to enter Ready mode.
- Check live data for discharge command and reported DC-link voltage decay, using the manufacturer's scan-tool procedure.
- Inspect accessible low-voltage discharge-control wiring and connectors for damage, corrosion, or looseness.
- Have a qualified technician test the discharge switch and resistor circuit using the manufacturer's high-voltage safety procedure.
- Confirm that the DC-link voltage reaches the manufacturer's specified safe state before any inverter service is attempted.
Common fixes
- Repair a damaged low-voltage discharge-control connector or wire.
- Replace a failed discharge switch identified by circuit testing.
- Replace an open or out-of-spec discharge resistor.
- Repair the inverter assembly if the discharge components are integrated and fail testing.
Can I keep driving?
Do not open or service the inverter or high-voltage system; the DC-link capacitors can retain hazardous energy after shutdown. If the vehicle will not enter Ready mode or electric drive is unavailable, arrange diagnosis and avoid driving it.
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.