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 without a transition of the stop lamp switch, the PCM sets DTC P1574.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1574 Stoplamp 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 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 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. Component Tests and General Diagnostics

Test

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