What it means
Throttle B is mechanically stuck open — typically carbon buildup or a broken return spring on the secondary throttle plate.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Throttle actuator B controls a secondary throttle plate in systems equipped with that actuator. P211A sets when the module detects that throttle B remains mechanically open instead of returning toward its commanded position, which can happen if deposits obstruct it or its return spring is broken.
Common causes
Most likely first.
- Carbon buildup holds plate open
- Return spring broken
- Carbon or debris buildup preventing free movement
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
How to diagnose it
- Record freeze-frame data and compare throttle B’s commanded and actual positions to confirm that the secondary plate is being reported open.
- Use the vehicle’s service information to locate throttle B, then inspect its plate and bore for carbon or debris holding it open.
- With the system safely powered down as directed by the maker, check whether throttle B’s plate and return mechanism move freely; do not force an electronic plate.
- Inspect throttle B’s actuator connector and wiring for damage, and check the return spring for breakage or disconnection.
- If the plate is clear and the mechanism intact, test throttle B’s actuator and position feedback circuits against the manufacturer’s specification.
Common fixes
- Remove carbon or debris that is holding throttle B open, using the approved cleaning procedure.
- Reconnect or replace a broken throttle B return spring or mechanical linkage where serviceable.
- Repair damaged throttle B actuator wiring or connector pins.
- Replace the throttle B actuator or body if it remains stuck open after mechanical and circuit checks.
Can I keep driving?
A secondary throttle stuck open can cause high or uneven idle and unpredictable acceleration, with possible reduced-power operation. Avoid driving if engine speed rises unexpectedly or the vehicle cannot maintain predictable throttle control.
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.