Conditions for Setting the DTC
WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
B3903 02
Will set if the stop lamp switch signal circuit is shorted to ground for 125 ms.
B3903 05
Will set if the stop lamp switch signal circuit is open or shorted to voltage for 125 ms.