I have a 2007 yukon xl. Came out of store and vehicle would not start. No crank. Dash lights up poeer windows radio work. Power door locks and remotes don't work. Also can shift vehicle into gear without puting foot on brake. And reverse lights stay on with key on. Code p1682. Replaced bcm. No change. Cleaned battery terminals and 175 amp fuse. Tested battery. Monitor range nsensor shows gear position. Tested relays underhood. Jumped starter relay and will crank over. Need advice anyone seen this

I would try a ignition switch.

I agree. I would normally say neutral safety switch, but those other symptoms indicate the ignition switch might be a good place to start.

Ok.I will try that..ill let you know

ok.installed ignition switch no change. Monitored neutral switch. Trans range reading properly on scan tool. Need more advice. Any more ideas out there

Hmm this is odd because the p1682 indicates a voltage drop past 9 volts. Is the code still active? What kind of scanner do you have? Can you look at PCM data and compare it to other modules data like the abs module? Seems like if the power and grounds are in good shape the PCM might be going Wacco.

I'm using a snap on scanner. I can communicate with all modules.

Check the positive starter cable if its "Loose" or secure enough connection ur starter wont kick over. If not maybe a Relay went bad

Excuse me I didnt read clearly. How bout bad crank shaft position sensor .I had a problem in my 93 old 88 royale . I had power ever where else but engine would not turn over only if I put the key in real fast & stared as quick as possible then it would start . I pinched a the for the crank sensor I dont know if this helps but stay stong

If it was a crank sensor he would have a crank no start issue. And since you can communicate with other modules including the bcm which you said you replaced the data line isn't compromised. I would say you need to get a diagram of the PCM inputs and check contanuity of the power and grounds and make sure the 5v reference has acceptable voltage and hasn't been ground by a bad sensor or wiring.