P056C: why a persistent cruise-cancel request disables cruise

P056C identifies a cruise-cancel input that remains applied too long in the documented GM strategy. The body control module reports the switch state to the engine controller; the engine controller evaluates persistence rather than simply detecting one press.

Two documented timing windows

The 03A table requires more than 20 seconds applied within a 25-second sample period. The 04B example instead specifies more than 89 seconds in 99 seconds and explicitly describes a momentary on/off switch architecture. These are different calibrations, so a single universal timeout would be misleading.

Interpreting the complaint

A cancel indication that stays active after the button is released is more informative than an ordinary cancellation during use. Comparing the reported cancel state with the physical button operation helps establish whether the persistent request is present now. That comparison is diagnostic reasoning, not proof of which switch or circuit component failed.

Both tables say cruise is disabled and disengaged for the remainder of the key cycle after failure, even if the current input subsequently passes. Consequently, a recovered live signal and continued cruise unavailability are compatible with this code. Record the original condition before using a new key cycle to assess recovery. Both examples classify the fault as one-trip, Type C, with no emissions MIL; an unlit engine warning lamp does not exclude it.

Source and applicability

Documented monitors in gm-2025-03a, gm-2025-04b, model year 2025. These are module/calibration examples; vehicle, engine and transmission applicability must be confirmed independently. GM 2025-03a, page 337. GM 2025-04b, page 559.