Truck ran fine but I let it sit a few months. Now the truck wont take off in drive as I have to down shift to get going and dosent want to shift properly. The speedo is also pegged then bounces. I also noticed the tripometer clicks off tenths as it is sitting still. p720 then p1693 are the codes that came up. Any help would be appreciated.

Thanks

 

The same two codes showed up on my 2001 a few weeks ago.

The first one,
P720 The Output Shaft Speed Sensor doesn't match the reported vehicle speed.

I crawled under my truck tonight and pulled the rear trans speed sensor (just ahead ot the transfer case on the L/S).
The tip of it is damaged and had metal chips stuck to it.
That's definitely gonna throw the signal out of whack.
I'm planning on installing a new speed sensor tomorrow, since the tip of the speed sensor is damaged.

The second one,
P1693 The companion engine control module has shown a fault.

That one should be because if the first one.

 

I changed that sensor even though my old one looked ok. Now I have to start in 2nd gear or the truck will stall in D from a stop. Once I get going I can shift into D and it shifts fine untill I stop. But with just the key on my speedo pegs and it clicks off tenths of miles not running and I get no other codes. It has to be another sensor or???

Thanks