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 ECM/PCM detects that there is a 4.2 km/h (2.6 mph) or greater decrease in vehicle speed within 0.25 seconds and a transition of the cruise/brake switch without a transition of the stop lamp switch, the ECM/PCM sets DTC P1574.

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 seconds.
- The ECM/PCM detects a cruise/brake transition.
- The ECM/PCM does not detect a stop lamp switch transition.

ACTION TAKEN WHEN THE DTC SETS
- The ECM/PCM sets the stop lamp switch status to released.
- The ECM/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 ECM/PCM receives a clear code command from the scan tool.

DIAGNOSTIC AIDS
In order to avoid a misdiagnosis, perform the following:
- Inspect for proper operation of the stop lamps.
- Inspect for proper adjustment of the stop lamps.
- Inspect for proper adjustment of the cruise control release switch.
- For an intermittent condition, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST

Steps 1-7: