P0573

Diagnostic Chart:

Schematic:

The stop lamp switch is used to turn On the stop lamps and serve as an input to the PCM and cruise control module (if equipped). The stop lamp switch has two internal independent switches; one is used for the stop lamps and the other for the PCM/cruise control module inputs. The switch for the PCM/cruise control module is closed and the switch for the stop lamps is open with brake pedal released and switch adjusted properly. Ignition voltage is supplied to the PCM and cruise control module through the stop lamp switch whenever the ignition is turned On and the brake pedal is released. When the brake pedal is depressed, the PCM/cruise control module inputs go low. The PCM monitors the stop lamp input for low and high voltage faults under certain conditions. DTC P0573 sets when the vehicle has been driven twice up to a calibrated vehicle speed and the voltage at the PCM remains high, indicating the brake is not being applied.

DTC PARAMETERS
DTC P0573 will set if ignition voltage is continuously present at the PCM cruise/brake switch input when the vehicle has cycled from 0-55 km/h (0-34 mph) twice in one ignition cycle.

DTC P0573 diagnostic runs continuously once the above conditions have been met.

DTC P0573 is a type D DTC.

DIAGNOSTIC AIDS
DTC P0573 can set falsely if the customer has driven the vehicle up to the calibrated vehicle speed twice while coming to a stop both times without using the foot brake.

To locate an intermittent problem, use Scan tool to monitor BRAKE SWITCH while cycling the brake. The Scan tool will read APPLIED when no voltage is present at the PCM cruise/brake input. Wiggling wires while watching for a change from APPLIED to RELEASED (with brake depressed) may locate the area where a shorted switch or short to voltage in the wiring could lie.

Make sure the brake switch is adjusted properly by watching the stop lamps go On and Off. A switch that is too close to the brake pedal and won't open and may set this DTC.