P1574

Electrical Diagram:

CIRCUIT DESCRIPTION

The Brake Lamp Switch is a normally open switch. When the Brake Lamp Switch is closed, the TAC senses ignition voltage on the Brake Lamp Switch signal circuit.

If the TAC senses a voltage on the Brake Lamp Switch signal circuit when the Brake Lamp Switch should be open, this DTC sets.


CONDITIONS FOR SETTING THE DTC

^ Engine speed is greater than 700 RPM.

^ Engine operates longer than 2.0 second.

^ 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.

^ Vehicle speed is decreasing at a rate greater than 10.4 MPH over a one second period.

^ The TAC does not detect voltage on the Brake Lamp Switch circuit when the Brake Lamp Switch should be closed.

^ The above conditions present for 1.5 seconds.


ACTION TAKEN WHEN THE DTC SETS

^ The PCM stores the DTC information into memory when the diagnostic runs and fails.

^ The Malfunction Indicator Lamp (MIL) will not illuminate.

^ The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC

^ A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.

^ The PCM battery voltage is interrupted.

^ Use a scan tool in order to clear the MIL/DTC.


DIAGNOSTIC AIDS

In order to adjust the Brake Lamp Switch perform the following:

1. With the brake pedal depressed, insert the Brake Lamp Switch into the retainer until the switch body seats in the retainer. You can hear clicks as you push the threaded portion of the switch through the retainer.

2. Slowly pull the brake pedal fully rearward against the stop until you can no longer hear the clicks.

TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table.

2. This step determines if the fault is present.

4. This step checks for a Stop Lamp Switch circuit for being shorted to B+.

9. This DTC will not report a pass. The scan tool status for this DTC will never report a pass. The scan tool will only display when the diagnostic fails. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.