P2006: swirl flaps fail to return after actuator shutdown

P2006 is labeled intake-manifold runner control stuck closed. The reviewed GM monitor defines a specific follow-up event: after P20F8 has already set and the actuator is no longer driven, the swirl flaps fail to return to their fully open default position.

A spring-return check after another fault

The test waits more than two seconds after driver shutdown to allow the spring to move the valve toward its default. It then compares the remaining position with a 50% threshold. A value above that threshold satisfies the documented failure criterion.

This sequence changes how the code should be read. The two-second interval is an enabling wait for return movement, not a general timer for detecting every closed flap. P20F8 is a prerequisite in this strategy, so its preceding position-control evidence is relevant to understanding why the return test occurred.

Qualification and verification

The diagnostic system must be enabled, without code clearing or end-of-trip activity in progress. The row also requires the listed swirl-position and actuator fault flags to be absent. Once the qualified error exists, no additional debounce is listed; the function runs on a 6.25-millisecond task and reporting is Type A, one trip.

Useful confirmation therefore observes the undriven return after the permitted delay, rather than only checking commanded motion while the motor is powered. The code does not identify the mechanical obstruction or justify a complete manifold replacement. These facts describe the documented 2025 GM swirl-motor monitor, with exact system applicability and physical testing left to vehicle-specific service information.

Source: GM monitor, PDF page 1378.