What it means
The control pilot charging switch B reports a stuck off 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 changes state as part of the charging system's control pilot handshake. P2DD3 sets when the module detects that switch B remains off when it expects the switch to activate, which can result from high-resistance contacts, a failed actuator, or debris preventing movement.
Common causes
Most likely first.
- Contacts oxidised - high resistance
- Actuator failed
- 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
- Review freeze-frame and live switch B state during a charging attempt to confirm it remains off when activation is expected.
- Inspect the switch B connector and wiring for corrosion, poor contact, damage, or a loose connection.
- Check whether the switch or its actuator moves freely and whether contamination is visibly obstructing it, following service information.
- Test switch B's contact response and circuit continuity against the manufacturer's procedure.
- If the switch changes state correctly at its connector, trace the signal to the charging controller and verify its input.
Common fixes
- Clean and secure the switch B connector if the service procedure allows.
- Remove accessible debris that is preventing switch movement, following service information.
- Replace a switch B assembly with oxidised contacts or a failed actuator.
- Repair wiring or the controller input if testing shows the switch state is not reaching the module.
Can I keep driving?
The vehicle is generally drivable, but charging may not begin or may be unreliable, so verify the charge before a trip that depends on it. Avoid forcing or repeatedly operating a switch that appears mechanically stuck.
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.