P2580: A turbo-speed input stuck low must also lack pulse progress

For P2580, the documented bank-one turbo-speed input remains low while pulse timing and pulse-count differences both fail to advance. The controller therefore checks more than a low instantaneous logic state. A normally switching input can be low for part of each pulse without meeting this fault pattern.

The missing transitions matter

The source requires at least 50 counts of the combined unchanged-pulse condition. The engine must exceed 1,500 rpm, supply voltage must be at least 9 V, and the boost-control-active flag must be false. Its listed failure interval is 500 ms, with two-trip reporting.

These gates explain why a sensor observation during another operating state may not exercise P2580. In particular, the table’s explicit boost-control flag should not be replaced with an assumption that the test runs only under commanded boost.

Useful verification evidence

Compare the electrical state with pulse progression, not merely the displayed turbo rpm. A stationary low signal with no new pulse information is the combination that matters here. Verify the channel identity against the vehicle’s wiring information and retain the controller’s enable status. The summary does not establish whether a wiring path, sensor supply or sensor internals caused the missing transitions.

Document scope and source

2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred. These figures explain the cited controller logic, not a vehicle-specific repair instruction. Match the vehicle’s service information before applying them.

GM physical PDF page 883, GM physical PDF page 884.