[wiswind]

I remember a post stating that if you select "2" on the gear selector....that the vehicle will not use 1st....and will start out in 2nd.
This would be consitant with a defective transmission range sensor, as metioned by MARZBX157

This SAME part is often called Neutral Safety switch....same part.....2 names.
If you unplug the TRS, the vehicle should not start....as the Neutral safety function prevents the vehicle from being started in in any gear selection other than Park, and Neutral......so the starter function passes through that electrical connection as well.

I have not done this.....so I am only repeating what I have read from other posts......
Do not do this on a steep hill.....you want to make sure that your parking brake will hold the vehicle from drifting......should the vehicle not properly shift back into "Park"......or into a gear when you select one....

What people have done, locate the plug.....and make sure that it comes off....and that you can safely get to it when the engine is running......set the parking brake.......start the vehicle......unplug the electrical connector to the TRS (Will cause a fault code to be set as the computer now sees that the TRS is "not there"), drive.......if it now uses all gears (but may shift very hard)....then the TRS is most likely the cause of you not having 1st gear.