In automotive technology, the corrosion resistance of variable surface finishes on automobile printed circuit boards (PCBs)represents a crucial topic. The key purpose of these surface finishes is to prevent corrosion between the Cu substrates in PCBs and corrosive SO2 gas in the automobile's working environment. In this study, the surface finishes deposited on PCBs were electroless nickel immersion gold (ENIG), immersion tin (ImSn), and electroless cobalt (EC). All samples were placed in a SO2 concentration of either 1500 or 4000 ppm at 80 °C for either 48 or 168 h. The ENIG samples tested at 1500 ppm SO2 showed massive corrosion products on the surface, even migrating to the solder mask. The ImSn and EC samples were also slightly corroded. At a SO2 concentration of 4000 ppm, corrosion of all surface finishes increased drastically. Notably, Cu was detected in the corrosion products formed on the ENIG and ImSn but not on the EC. The EC coating has the potential to be an effective anticorrosion surface finish for automobile PCBs.