Brake Signal: Description and Operation

PURPOSE
The Brake On Off (BOO) signal is an input to the Powertrain Control Module (PCM), informing it of brake operation. The PCM uses this data to modify the operation of the torque converter clutch (if equipped), A/C compressor (if equipped), and idle speed during periods of deceleration, and idle with the brakes applied.

Stoplight Switch:

OPERATION
The PCM receives a signal (battery voltage) directly from the stoplamp switch when the the brake pedal is applied.

RELATED TROUBLE CODES

DTC 74/536 - BOO signal did not cycle high and low when the brake pedal was depressed during the Key On Engine Running (KOER) self-test.