Idle control using ETB
ETB idle control is a cascade. The idle controller determines a position from its open-loop table plus optional closed-loop RPM correction. applyIACposition() sends that position to every ETB controller. In the normal non-torque-model path, ETB target logic converts it into a throttle target, then the separate ETB position PID drives the plate until physical TPS matches.
Which feedback does what
With an accelerator-pedal input configured, DriverThrottleIntent comes from the combined pedal sensor instead of TPS. The idle TPS threshold therefore tests pedal demand on an ETB car. The idle RPM PID uses target versus engine RPM; throttle-body TPS is not its feedback.
For the normal target path, ETB idle maximum angle × idle position / 100 becomes the range's low endpoint. Pedal-table demand interpolates from there to 100%, so increasing idle position raises the closed-pedal target without adding the same amount at wide-open pedal. Idle position is clamped to 0-100%. With the torque model enabled, the target is the model request capped by the pedal table; this remap is not applied, so validate idle behavior for the selected strategy.
Open-loop idle position always applies. Closed-loop correction requires Open Loop + Closed Loop mode and a valid driver-intent signal; an invalid signal omits correction. Configure RPM targets and general idle behavior in Advanced Idle Control; this page covers only ETB interaction.
The optional Idle-only RPM feedback: Rolling cycle setting replaces instantaneous RPM for closed-loop idle air and timing. It does not change the ETB position loop, which still uses throttle-body TPS. Until one complete cycle is valid, idle air retains instantaneous feedback. See Advanced Idle Control for the shared setting and fallback.
Log Idle position, Idle: Target RPM, idle PID terms/error, Target, physical TPS, ETB: position error, and ETB: Duty. If idle position changes but body TPS does not follow, check calibration, position limits, paused/stopped-engine disable, rev limiting, jam protection, and the H-bridge before changing gains. A low pedal does not guarantee a zero target.