My car won't start and says no bus in the odometer window. Battery is good I checked for spark and it has good voltage.
The "no bus" message indicates that the instrument cluster is not getting any messages from the other computer systems in the vehicle. The computers communicate with each other on a two wire communication network called the CAN BUS system similar to a LAN at work or home. If the CAN BUS isn't functioning correctly (some of the sensors and modules are shorted) then the odometer will display no bus and none of the other electric systems in your Nitro will function properly including the alarm, radio, signal lights and wipers.
Disconnecting the negative battery cable for 10 minutes can reset the CAN BUS system so the odometer will display the correct mileage. If you are unable to get the no bus error to go away you may need to replace one of the sensors that is sending signals to the odometer. Checking the crankshaft position sensor is a good place to start. It is located in the transaxle bellhousing and it can be replaced easily. Replace the bolt and then reconnect the electrical connector and you will be good to go.