I bought a minorly totaled 2018 CX-9 Touring and I'm fixing it up myself. It's missing the front grill and attached sensors and was obviously showing the warnings, "forward smart city brake support malfunction" and "front camera sensor system malfunction". I expect that after I connect the new sensors behind the grill, those warnings will be able to be cleared. It started and ran just fine, drove it a block home after the tow truck dropped it off. I noticed that the red light on the FOB was flashing, so I replaced the battery in the FOB (with the same voltage battery), then the car wouldn't start AND the security icon lights up on the dash and now it's showing even more warnings, "blind spot monitoring sensor malfunction", "front radar sensor system malfunction", "smart brake system malfunction", "battery management system malfunction", "keyless system malfunction", "power steering malfunction", "charging system malfunction, stop vehicle in a safe location" plus the original two warnings and others that appear on the navigation screen. I tried disconnecting the battery for a day, reconnecting it, nothing. I put the old dying battery back in the FOB, nothing. The doors will unlock with the key, but not the trunk. I've looked for others with this issue and haven't found any other forums on it. Please Help!

 

Look into Forscan to check and clear error codes. You will need a laptop and OBDII adaptor also. The forscan website has recommendations for adaptors.