P0571

DTC P0571

CIRCUIT DESCRIPTION
The cruise brake switch is a normally closed switch. The stop lamp switch is a normally open switch. When the brake pedal is released, the engine control module (ECM) detects a high voltage signal on the cruise brake switch signal circuit and a low signal voltage signal on the stop lamp switch signal circuit.

CONDITIONS FOR RUNNING THE DTC
- The engine speed is greater than 700 RPM.
- The engine operates for greater than 2 seconds.
- The ECM detects that the condition exists for 20 consecutive times in one ignition cycle.

CONDITIONS FOR SETTING THE DTC
DTC P0571 will set when the ECM detects one of the following conditions:
- A high signal voltage on the stop lamp switch signal circuit and a high signal voltage on the cruise control release signal circuit.
- A low voltage signal on the cruise control release signal circuit and a low signal on the stop lamp switch signal circuit.

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

CONDITIONS FOR CLEARING THE DTC
- A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
- 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.
- Use a scan tool in order to clear the DTC.

DIAGNOSTIC AIDS
- Inspect for proper adjustment of the cruise/brake switch, refer to Cruise Release Switch Adjustment.
- Inspect for proper operation of the stop lamps, refer to Exterior Lighting Systems Description and Operation in Lighting Systems.
- For an intermittent condition, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST

Steps 1-11:

Step 12: