Brake Signal: Description and Operation

PURPOSE
Illuminates brake lights and signals PCME when brakes are applied.

LOCATION
Brake light switch is beneath dash adjacent to brake pedal linkage.

OPERATION
The PCME monitors the brake light circuit. When the brake pedal is released, the voltage in the brake light circuit is zero. When the brake is applied, voltage in the circuit goes high (approx. battery voltage). The PCME detects the voltage potential and assumes the brake is applied and a deceleration condition exists. This information is used in PCME calculations for idle speed control and fuel injection quantity.