Brake Signal: Description and Operation

PURPOSE
The Brake On/Off (BOO) switch signal is one of several inputs used by Powertrain Control Module (PCM) to calculate regulation of fuel control system.

OPERATION
When the service brake is applied, the stop light switch sends a signal to the PCM in addition to illuminating the brake lights. The PCM reads this signal as a deceleration indicator and uses it to regulate fuel injection quantity during this operating phase.