P1575

CIRCUIT DESCRIPTION
This diagnostic test functions on the assumption that a brake application causes a sudden decrease in non-drive wheel speed.

The extended travel brake switch is a normally closed switch. When the extended travel brake switch is closed, the powertrain control module (PCM) senses ignition voltage on the extended travel brake switch signal circuit.

If the PCM senses a voltage on the extended travel brake switch signal circuit when the extended travel brake switch should be open, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
^ The engine speed is greater than 700 RPM.
^ The engine has been operating longer than 2 seconds.
^ The wheel speed must be greater than 30 MPH in order to enable the diagnostic. The diagnostic will disable when the wheel speed is below 10 MPH.
^ The vehicle speed is decreasing at a rate greater than 2.6 MPH over a 250 millisecond period.

CONDITIONS FOR SETTING THE DTC
^ The PCM detects voltage on the extended travel brake switch circuit when the extended travel brake switch should be open.
^ The above condition is present for 1.5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The control module stores the DTC information into memory when the diagnostic runs and fails.
^ The malfunction indicator lamp (MIL) will not illuminate.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
^ The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
^ 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.
^ Clear the DTC with a scan tool.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the powertrain control module/throttle actuator control (PCM/TAC) module connector surfaces before servicing the PCM/TAC module. Inspect the PCM/TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM/TAC modules.
^ For any test that requires probing the PCM or probing a component harness connector, use the connector test adapter kit J 35616-A. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagnostic Aids.
^ Test drive the vehicle if you cannot find a problem with the switch or the circuit. An intermittent condition may be duplicated on a test drive.
^ This DTC does not set for an open circuit. If the PCM senses the Extended Travel Brake switch is Applied when the brake pedal is actually released a driveability concern may result.
^ If a condition is intermittent, refer to Symptoms-Computers and Controls Systems. Symptom Related Diagnostic Procedures

TEST DESCRIPTION

Steps 1-8:

Steps 9-18:

The numbers below refer to the step numbers on the diagnostic table.
2. An extended travel brake switch signal that indicates Applied when the pedal is actually released may cause a driveability concern.
4. An extended travel brake switch that is not properly adjusted may cause this DTC to set.
6. This step tests for an extended travel brake switch circuit for being shorted to battery voltage.