2015 Chevy Tahoe LT...changed out alternator and new battery at same time, put back together can will not crank. Power comes on and info board says to turn steering wheel (I can't due to it not starting), I dismiss info board and still won't start.
Tested all fuses, relays and voltage to alternator, battery, starter and everything is good. What is going on and how can I get this fixed? I'm parking inside my garage and can't move it.

 

You scan for any OBD II codes yet?

 

 

Codes: P1682 Engine 1 Switch Circuit 2
P0685 Engine Controls Ignition Relay Control Circuit

 

You were lucky to have a retired mechanic look over your vehilce. He is saying that the ECM needs reprogramming, assuming it is having issues.

 

P1682 and P0685
Also, my truck intermittently can start through remote start which then I have availability to hit the start button on truck but once I turn off I can't turn back on through start button on truck. It also appears that I have to wait out a while before I'm able to start it again through the remote and its a unlock, lock....lock, lock, start sequence on remote to start it through remote -very odd.

 

P0685 code: One of the most common reasons is a bad PCM relay. Could be a a blown fuse, a shorted circuit, a faulty connection, battery problems such as a cable defect, or a bad PCM or ECM.

The P1682 code: there is a difference in voltage between the ignition switch circuit 1 and circuit 2. There are a few things that can cause this - including a fault with the ignition switch itself or a fuse or relay in the circuit.

I am not familiar with remote start or key fobs with remote start, but its likely that you have something like a bad PCM/ECM relay or ignition relay. Might be a bad ignition switch, but not likely, IMO..

 

I just replaced alternator on my 2016 and having same problems. Can lock and unlock with the fob but no start. What did your problem end up being?

 

Yea always nice to wrap up a thread for future issues someone else may have. I too am curious what the fix was.