What does code P218A mean?

DTC codes / P21xx · Fuel and air metering / P218A

P218AThrottle Actuator B Control System - Idle Position Not Learned

P218A indicates that the engine control module (ECM) cannot learn or store the idle position for throttle actuator 'B', which is typically the second throttle plate in a dual-throttle system or a specific actuator circuit. The ECM expects to see a consistent idle position during closed-throttle operation but instead detects a position that falls outside the learnable range or fails to stabilize, so it sets this code and may illuminate the check engine light.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.