P1574
DTC P1574
Circuit Description
This diagnostic test functions on the assumption that a sudden decrease in vehicle speed is caused by a brake pedal application. When the powertrain control module (PCM) detects that there is a 4.2 km/h (2.6 mph) or greater decrease in vehicle speed within 0.25 second and a transition of the torque converter clutch (TCC) brake switch/cruise release signal without a transition of the stop lamp switch, the PCM sets DTC P1574.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1574 Stop Lamp Switch Circuit
Conditions for Running the DTC
* DTCs P0502, P0503, P0719, and P0724 are not set.
* The engine speed is greater than 700 RPM.
* The traction control system (TCS) or the antilock brake system are not active and have not failed.
* The vehicle speed is greater than 48 km/h (30 mph) in order to enable the diagnostic.
* The diagnostic will disable when the wheel speed is less than 16 km/h (10 mph).
Conditions for Setting the DTC
* The vehicle speed decreases by at least 4.2 km/h (2.6 mph) within 0.25 second.
* The PCM detects a TCC brake/cruise release signal transition.
* The PCM does not detect a stop lamp switch transition.
Action Taken When the DTC Sets
* The PCM sets the stop lamp switch status to released.
* The PCM disables the operation of the cruise control system.
Conditions for Clearing the DTC
* A history DTC will clear after 40 malfunction-free warm-up cycles.
* The PCM receives a clear code command from the scan tool.
Diagnostic Aids
Refer to Exterior Lighting Systems Description and Operation in order to avoid a misdiagnosis.
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics
Test
