Obd2 port not communicating and very rare no crank condition

[VikingTrad3r]

2006 Yukon XL Denali with 300,000 miles.

Do you guys think it’s possible that these two things are related:

An OBD2 plug failing most of the time, getting stuck on a 53% boot or load on the scanner, and secondly a very rare no crank condition is experienced in our car?

The obd2 situation is that it simply will not connect to the computer. We had an aftermarket remote starter installed so i assumed it was that devices fault. i went in today to have the tech remove the remote starter and restore the vehicle to stock. Even after being returned to stock condition it did not help. Still no connection to the computer.

So i had him put it back as my wife really likes the remote start.

——-

The second condition is strange. It has happened 2 times in our 4 year ownership. my wife puts the key in and turns it to the start position but the dash goes black and nothing happens. When she releases the key to the on position does dash lights return. Everything will function but the car will not crank.

Comments welcome please.

 

[rockola1971]

Id have to have a good look at the electrical schematic for your year/model but the no crank condition sounds like a ignition switch (the electrical one, not the mechanical one your key goes into) could be the culprit. They are mounted down on the steering column. Possibly anti theft system too. Schematics and voltmeter will tell all. Start pulling panels under dash on drivers side. OBD2 may or may not be related but an easy check also with voltmeter. There are only like 4 wires or so involved. Power, ground and comm wires going to PCM.

 

[Doubeleive]

I would start with the battery and battery cables, be sure the battery is good and cables are clean

 

[Big Mama]

Especially the ground locations not just the battery.

 

[VikingTrad3r]

Thanks guys, let’s keep the brain storms coming.

 

[Big Mama]

Another thread I was following just reported back a bad ground and a broken wire was his problem.

 

[OR VietVet]

I would start with the battery and battery cables, be sure the battery is good and cables are clean

Like recommended, always start with the basics and work out from there.If you don't have a known good battery and good clean/tight connections at all cables and wires from that battery, you got problems to the other areas that need that known good start.

 

[W M S]

I just worked on my daughter's 04 Denali with 230K miles and after-market remote start/alarm, for a dead battery (1 year old & OK).

Once it was jumped the I/P had no gauges or lights except MIL, ABS, and Battery. There was No Comm with Autel scan tool.

Also, windows, locks, and A/C were inop, but there was fan & heat.

I started removing class 2 modules from the network. When I removed the connections from the after-market remote/alarm module to the network at the ALDL connector and the BCM, the network communication was restored.

Like the previous poster, I removed the module, restored the wiring back to original and cleared the multiple U-Codes.

The Yukon has been OK for over a week.

Prior to this, it would occasionally crank but not start.

It also had a slow crank almost all the time.

A new ACDelco starter, new ACDelco ignition switch, and clean battery and ground cable connections have given this old Yukon what it needs to spin-over like a new truck.

I hope this helps.

Best of luck.

 

[swathdiver]

I started removing class 2 modules from the network. When I removed the connections from the after-market remote/alarm module to the network at the ALDL connector and the BCM, the network communication was restored.

How'd you do that? Just got our Montana back running after a couple of months, open door and it act like key is in ignition, bing bing bing, sound. No instrument cluster lights, Tech-2 cannot talk to anything. It starts, runs and drives, running lights, head lights work, AC works, etc. Wife took it to work today.

 

[W M S]

For my vehicle (daughter's), the wiring diagrams from BBB Industries (you now have to register to get access), show Splice Packs (SPxxxx) where the class 2 lines from the different modules are connected. If you have easy access to them that is a simple way to eliminate the offending module/wire.

In my case, I found it easier to see which modules were connected and easy to disconnect. The splice packs are up under the top of the dash! A real pain to get to.

I got lucky and hit on the bad module on the 3rd try, after the HVAC and IP.

Good luck.