Your car's brake switches aren't agreeing with each other about whether the brakes are being pressed. Think of it like two security guards at a door who keep giving different answers about whether someone entered.
The ECM monitors dual brake switch inputs (typically a primary and redundant switch) to verify brake pedal status for safety systems like cruise control and emission controls. The switches should activate and deactivate in correlation; if their signals diverge beyond acceptable timing, the fault triggers.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Brake Switch A to B Activation Delay | < 100 milliseconds correlation | > 100 ms or no correlation detected |
| Switch Signal State Agreement | Both switches match (on/off simultaneously) | Switches in disagreement for > 1 second |