P0564: Cruise switch voltage falls between valid command ranges

P0564 is the cruise-control multifunction input circuit code. In the cited legacy GM system, the body controller interprets an analog switch circuit and tells the engine controller when its value lies between valid command ranges. The fault is an invalid encoded input, not necessarily an unwanted valid button command.

Gaps between recognized commands

The page lists several narrow analog-to-digital ratio bands that are considered invalid. These are ratios, not direct voltage values to apply at a connector. The monitor reports failure when the invalid state occupies 0.50 seconds within a 25-second sample period, with the CAN cruise-switch diagnostic enabled.

This distinguishes P0564 from a switch that remains in one valid command range too long. Recording the raw ratio and decoded switch state can show which behavior the controller actually saw.

Cruise can remain unavailable after the signal recovers

The documented default action disables and disengages cruise for the remainder of the key cycle once the fault occurs, regardless of later pass/fail state. A currently valid switch reading can therefore coexist with cruise still disabled.

Use the applicable switch-circuit and module-data procedure to determine why the input falls between ranges. The code does not establish a steering-wheel switch replacement by itself. Verification should show valid command decoding and a completed monitor after correction. The source lists Type C, one-trip reporting with no emissions malfunction-lamp request.

Source and applicability

This explanation is limited to the 2025 GM 25OBDG03A monitor on page 333. Its thresholds are calibration examples, not universal specifications. Confirm the vehicle, engine and controller procedure before applying them.