What it means
The control pilot charging switch B reports a stuck on condition. SAE J1772 charging signal handshake may be compromised.
At a glance
- Usually lights the check-engine light
How it works
The control pilot charging switch B is part of the circuit that signals between an EV and its charging equipment during the J1772 connection handshake. The vehicle monitors whether switch B changes state as commanded. This code sets when the switch continues to report on, which can disrupt the handshake.
Common causes
Most likely first.
- Contacts welded closed
- Driver stuck on
- Carbon or debris buildup preventing free movement
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Record freeze-frame data and charging-system codes to see when the fault occurred and whether it coincided with a failed or interrupted charge.
- Check the charge-port status indicator and inspect the connector and port for contamination, damage, or signs of overheating.
- With the vehicle safely disconnected from charging equipment, inspect the control-pilot switch B wiring and connectors for loose, corroded, or damaged contacts.
- Use a scan tool to compare the commanded state of switch B with its reported state during the manufacturer's specified charging-system test.
- If the wiring and connections are sound, test switch B and its driver circuit for sticking or welded contacts using the manufacturer's procedure.
Common fixes
- Clean debris from the charge-port or switch area using the manufacturer's approved method.
- Repair damaged or poorly seated control-pilot switch B wiring or connector contacts.
- Replace control-pilot switch B if its contacts are stuck or welded closed.
- Repair the switch B driver circuit if it remains energized after the module commands it off.
Can I keep driving?
Avoid relying on the affected charge connection if charging will not start or keeps interrupting; use another compatible charging point if available. Stop charging if you notice heat, smoke, or a burning smell, since a stuck switch or damaged contacts can worsen.
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.