What it means
Throttle actuator B motor drive line stuck high — short to B+. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Throttle actuator B is the motor that moves a secondary throttle plate on engines fitted with two throttle bodies. The control module monitors the B motor drive line and sets P210D when that line is held at an abnormally high level, often because it is shorted to battery voltage.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
How to diagnose it
- Use a scan tool to save freeze-frame data and check for other throttle actuator B or power-supply codes that may point to the source of the high signal.
- Inspect the B motor connector for corrosion, moisture, displaced pins, or signs that a supply wire has contacted another terminal.
- Trace the throttle actuator B wiring for pinched insulation or contact with a battery-positive feed, paying close attention to harness crossings.
- Using the wiring diagram and proper circuit isolation, check whether the B drive wire is shorted to battery voltage.
- If the wiring and connector pass, test the B motor circuit and control driver according to the manufacturer's diagnostic procedure.
Common fixes
- Repair a pinched or chafed throttle actuator B wire that is contacting a power feed.
- Replace damaged or corroded B motor connector terminals and restore the connector seal.
- Repair harness routing or protection where it allowed the B circuit to contact battery voltage.
- Replace a failed B motor or control driver only when testing confirms the component is faulty.
Can I keep driving?
Limit driving to a safe place for diagnosis if throttle response is reduced or unpredictable, and avoid high-speed roads. A high B drive signal can disrupt secondary throttle control and may lead to reduced power or unstable engine behaviour.
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.