PO698 sensor reference; voltage ceased; circuit low. The car doesn't start. Where should I start?
The first thing you want to do is have a certified mechanic unplug the main computer and test the wires coming out of it. Either the wiring is bad, or the computer’s connectors have a little condensation and corrosion, which won’t let it work properly. Follow the wire to the sensor to check the wiring and sensor itself.
Pray that it’s not the main computer because that’s an expensive job to fix. You’ll have to install a new computer and get it reprogrammed. It’s a really big job, so hopefully the problem is with the wiring or sensor itself. A certified technician will be able to take a look at your car to determine a fix for your starting problem.