P1574

CIRCUIT DESCRIPTION
The stoplamp switch is a normally open switch. The switch receives a fused battery voltage, and grounds through a pull-up resistor in the Turn/Hazard flasher module. With the brake pedal NOT applied, the Turn/Hazard flasher module should detect a low signal voltage on the stoplamp switch circuit. The Turn/Hazard flasher module sends the input state of the switch to the PCM via class 2 serial data. The PCM uses the data to determine the condition of the switch. With the brakes applied, the PCM compares the stoplamp switch input to the TCC and/or ET brake switch input. It a transition occurs on the TCC and/or ET brakes switches without a transition on the stoplamp switch, DTC P1574 will set.

CONDITIONS FOR RUNNING THE DTC
^ The engine speed is more than 500 RPM.
^ No VSS, TCC brake switch, ET brake switch, or EBCM Serial Data DTCs are set
^ The traction control and antilock brake systems have not tailed
^ The traction control and antilock brake systems are not active.
^ The VSS achieves 32 KPH (20 MPH) and remains above 5 KPH (3 MPH).
^ The difference in speed between the driven wheels and the non-driven wheels is less than 10 KPH (6 MPH).

CONDITIONS FOR SETTING THE DTC
The PCM detects a signal transition on the TCC and/or ET brake switches without a transition on the stoplamp switch

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM disables cruise control.
^ The PCM will set the stoplamp switch status to applied.
^ The PCM will store conditions which were present when the DTC set as Failure Records only.

CONDITIONS FOR CLEARING THE MESSAGE/DTC
^ The PCM will request that the message be turned OFF after one diagnostic test has been run and passed.
^ The History DTC will be cleared after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.

TEST DESCRIPTION

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