Mazda 6 2014 immobiliser issue after infotainment upgrade
Ok, so I installed a pioneer infotainment upgrade to my Mazda 6 2014, it all worked fine until I took it to my local garage because the horn stopped working. When I got it back it would not turn off the system at all so when I got home I disconnected the negative terminal from the battery, unplugged the infotainment system and put back in the old one. When I reconnected the negative terminal the system instantly turned on, but the car wouldn’t start. The key seems to no longer be synced with the car
I have tried disconnecting the battery for 10 minutes, holding the key against the start button but nothing happens and the immobiliser light is just flashing, the break pedal feels stiff as hell, like it will not press down at all. Does anyone have any advice? Should I leave the negative terminal disconnected for longer?