What it means
The control pilot charging switch B reports a range/performance condition. SAE J1772 charging signal handshake may be compromised.
At a glance
- Usually lights the check-engine light
How it works
Control pilot charging switch B contributes a signal used by the charging system's control pilot handshake. P2DCF sets when the module sees switch B's response outside the expected range or behaving poorly, rather than a clear open or consistently low or high circuit state.
Common causes
Most likely first.
- Switch contacts aged
- High-resistance contact
- Sensor element aged beyond calibration window
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Review freeze-frame and live charging data to see what switch B reports during a failed or interrupted charging handshake.
- Inspect switch B's connector and wiring for looseness, corrosion, wear, or signs of heat that could create a resistive connection.
- Check the switch B circuit and contact condition using the manufacturer's test procedure and specification.
- Monitor switch B's signal while operating the charging system to see whether it changes smoothly and consistently.
- If wiring and contacts are sound, test the switch and charging controller input to identify whether the signal is outside calibration.
Common fixes
- Clean and secure the switch B connector if service information permits.
- Repair a high-resistance terminal or damaged section of wiring.
- Replace worn or intermittent switch B contacts or the switch assembly.
- Repair the charging controller input only if testing confirms a controller fault.
Can I keep driving?
You can generally drive the vehicle, but charging may be slow, fail to start, or interrupt, so verify the charge before relying on it for a trip. Avoid repeatedly disconnecting and reconnecting charging equipment to work around the fault.
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.