P0580: low cruise-switch voltage is architecture dependent

P0580 detects a low analog cruise multifunction-switch input in the cited GM momentary on/off architectures. The BCM reports the condition to the engine controller, which can disable cruise for the remainder of the key cycle.

What low means here

The documented boundary is an analog-to-digital count ratio from 0 to 0.185. It is a ratio, not a voltage specification. Both examples require the failure indication for two seconds within a 25-second sample period. The useful observation is therefore a sustained low-range report, not merely one low sample during switch operation.

The 04B table says certain Global A implementations also classify an open cruise-switch circuit under this low-input code. That prevents a common overinterpretation: P0580 does not universally prove a short to ground. The actual switch architecture determines how an open circuit appears.

Recovery and source differences

Cruise remains disabled for the key cycle after the documented failure, even if the present input returns to a passing state. Check the underlying signal and the key-cycle history separately when a normal input accompanies unavailable cruise.

The sources also differ in reporting classification: 03A lists Type C with no emissions MIL, whereas 04B lists Type B over two trips. Do not promise a particular warning-lamp behavior from the generic code alone. Verify the vehicle's architecture and calibration before selecting the circuit diagnostic or interpreting a successful repair.

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 345. GM 2025-04b, page 564.