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 seconds and a transition of the cruise/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 P0717, P0722, and P0161 are not set.
- The engine speed is greater than 700 RPM.
- The traction control system (TCS) or the antilock brake system (ABS) 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 PCM detects a torque converter clutch (TCC) brake switch/cruise release signal transition.
- The PCM does not detect a stop lamp switch transition.

ACTION TAKEN WHEN THE DTC SETS
- The cruise control system is disabled.
- The PCM stores the DTC information into memory when the diagnostic runs and fails.
- The PCM records the operating conditions at the time the diagnostic fails. The PCM displays this failure information in the Failure Records.
- The malfunction indicator lamp (MIL) will not illuminate.

CONDITIONS FOR CLEARING THE DTC
- A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
- use a scan tool in order to clear the DTC.

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

TEST DESCRIPTION

Step 1 - Step 10:

The number below refers to the step number on the diagnostic table.
10. DTCs will set in the transmission control module (TCM) and the powertrain control module (PCM) when you perform this diagnostic table.