P0571

DTC P0571

CIRCUIT DESCRIPTION
The brake pedal switch is installed on the brake pedal bracket. The brake pedal 1 switch is a normally open type switch and the brake pedal 2 switch is a normally closed type switch. When the brake pedal is pressed, the brake pedal 1 switch signal is provided to the engine control module (ECM) and the stoplights are turned ON. Then, the brake pedal 2 switch signal to the ECM is stopped (low voltage) and the ECM cancels the cruise control. If the ECM detects the brake switch signals out of correlation, this DTC will set.

Condition for Running the DTC
- DTCs P0500, P0642, P0643, P0652, P0653, P0698 and P0699 are not set.
- The battery voltage is between 10-16 volts.
- The ignition switch is ON.

Condition for Setting the DTC
- The ECM detects a brake pedal 1 switch (normally open type switch) signal and brake pedal 2 switch (normally closed type switch) signal correlation error for 3 seconds while heavy braking.

Action Taken When the DTC Sets
12,000 lbs GVW
- The ECM illuminates the service vehicle soon (SVS) lamp when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.
- The ECM inhibits the cruise control.
- The ECM inhibits the PTO control.

Except 12,000 lbs GVW
- The ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive driving cycle when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Freeze Frame/Failure Records on the second consecutive driving cycle when the diagnostic runs and fails.
- The ECM inhibits the cruise control.
- The ECM inhibits the PTO control.

Condition for Clearing the MIL/DTC
12,000 lbs GVW
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic after the ECM turns OFF the SVS lamp.
- Clear the SVS lamp and the DTC with a scan tool.

Except 12,000 lbs GVW
- The ECM turns OFF the MIL when the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic after the ECM turns OFF the MIL.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
If an intermittent condition is suspected, the following may cause an intermittent:
- Faulty brake pedal 1 or 2 switch
- Misadjusted brake pedal switch
- Poor connections
- Misrouted harness
- Rubbed through wire insulation
- Broken wire inside the insulation

Check for the following conditions:
- Poor connection at the ECM: Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness: Inspect the wiring harness for damage. If the harness appears to be OK, observe the "Stoplamp Pedal Switch (Brake Pedal 1 Switch)" and "Cruise Release Brake Pedal Switch (Brake Pedal 2 Switch)" display on the scan tool with the ignition ON and engine OFF while moving connectors and the wiring harness related to the switch. A change in the display will indicate the location of the fault.

DTC P0571
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

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