P0420 - Meaning, Causes, Symptoms, & Fixes - FIXD Best Mar 06, 2018My 2003 Chevy Avalanche is throwing both P0420 and P0430. With the advanced troubleshooting on the FIXD it is telling me that the evap system is failing. I have replaced the vent valve and the purge valve and the gas cap. Brake Buddy Stealth Supplemental Braking System The diagram above shows how the 7-way flat installs. Wire 1 connects to your vehicle's battery. Wire 2 connects to the vacuum pump included with the Stealth. Wires 3, 4, and 6 connect to the corresponding, color-coded wires on the Stealth's main unit. These wires have quick-plug ends for simple plug-and-play connecting. Wire 5 is the ground wire.