Weird key issue, truck wouldn't start with primary key. Passlock disabled.

[2010H3TAlpha]

Going on a couple weeks now with the new relay and no issues yet. Hopefully $6 is all I needed to throw at this.

 

[RamRod]

Which relay did you replace? (Number in the fuse box)

Sent from my SM-G935W8 using Tapatalk

 

[2010H3TAlpha]

#78

It's happening again, luckily at home this time but still super annoying. I took video this time. I just get flashing passlock and constant check engine when I turn the key, nothing else, not single sound from the starter, etc.:

<a href="https://youtu.be/BGTEjn3G-gA" target="_blank">[video=youtube_share;BGTEjn3G-gA]https://youtu.be/BGTEjn3G-gA[/video]

 

[rascole]

If the relay worked once try it again. Check voltage at the starter when the key is turned over.

 

[2010H3TAlpha]

Thanks, that was my next plan, but then the truck randomly started. Now I can't get the issue to reproduce, so not sure what to do until it happens again. What a puzzle...

I know these starter switches are known for going bad, would it act like this if it needed to be replaced?

 

[Traxx]

The module on the back of the switch takes about ten minutes to replace. Same thing mine did when it went bad.

Thanks, that was my next plan, but then the truck randomly started. Now I can't get the issue to reproduce, so not sure what to do until it happens again. What a puzzle...

I know these starter switches are known for going bad, would it act like this if it needed to be replaced?

 

[2010H3TAlpha]

The module on the back of the switch takes about ten minutes to replace. Same thing mine did when it went bad.

Thanks! So I just need the black part from the back of this one?

https://www.amazon.com/Wells-LS1454...ie=UTF8&qid=1499790551&sr=8-2&keywords=Ls1454

 

[RamRod]

Thanks, that was my next plan, but then the truck randomly started. Now I can't get the issue to reproduce, so not sure what to do until it happens again. What a puzzle...
QUOTE]

This is the same problem that I was having when I wasn't getting a signal to my fuel pump.... then it would stop working in the middle of the worst possible location...

Hope you get it figured out!

 

[Traxx]

Yep that's the one. Replacing the whole switch is a pain, just need the back portion of it. I usually leave stuff like that in the cart and wait for amazon to drop the price, I paid just under 50 for mine.

Thanks! So I just need the black part from the back of this one?

https://www.amazon.com/Wells-LS1454...ie=UTF8&qid=1499790551&sr=8-2&keywords=Ls1454

 

[2010H3TAlpha]

Yep that's the one. Replacing the whole switch is a pain, just need the back portion of it. I usually leave stuff like that in the cart and wait for amazon to drop the price, I paid just under 50 for mine.

Ha, I definitely overpaid, but also wanted to get this done before taking the family to Rainier tomorrow. Here's the guide I followed:

https://www.hummerforums.com/forum/hummer-h3-17/need-help-changing-ignition-switch-33080/#post312326

I skipped the part about the key learning as my Passlock is disabled and my truck fired right up. Sweet! I have an extra ignition lock cylinder now, free to a good home.

Thanks, that was my next plan, but then the truck randomly started. Now I can't get the issue to reproduce, so not sure what to do until it happens again. What a puzzle...

This is the same problem that I was having when I wasn't getting a signal to my fuel pump.... then it would stop working in the middle of the worst possible location...

Hope you get it figured out!

Interesting, so yours wouldn't crank either? What part did you replace?

 

[RamRod]

Interesting, so yours wouldn't crank either? What part did you replace?

For me it wasn't that it wouldn't crank it was that I would have intermittent loss of signal to the fuel pump, never did figure out the true cause of the issue and I just made a work around to get the truck back on the road

 

[2010H3TAlpha]

Well, it has happened again. Thank goodness it was in my driveway this time, but what a pain. Breaking out the voltage tester tomorrow to see what's up with the starter, etc.

 

[mjferencak]

That sucks. Look for any frayed wires that might be grounding out/arching and shorting out the module.

 

[2010H3TAlpha]

Main voltage to starter is getting 12v, but no voltage at the signal wire when cranked. So it seems like another issue between the key and the signal wire. Already replaced the starter relay and starter switch, what else could there be? Visual inspection of wiring looks good, no frays or loose wires. I think I'm ready to take it to the shop

 

[2010H3TAlpha]

Had it towed to the shop. Just about ready to drive it into a lake, so hopefully they can figure it out soon.

 

[2010H3TAlpha]

Okay, shop #1 cannot get any signal to the throttle body so passlock is disabled somewhere in the system. I have passlock disabled via PCM of NC tune, so does this mean my TDM has failed? The truck is now headed to a Chevy dealer for diagnostics but I am expecting a $1k TDM replacement bill. I'd rather get rid of the system completely, would this do the trick? http://newrockies.com/passlock-bypass-2/

 

[Traxx]

Take it to a dealer and they will likely reflash your pcm in order to troubleshoot the system. Trying to disable the Passlock system just seems to cause more problems than it cures. I have close to 225k miles between a few H3's and have had to replace only one ignition switch.

 

[2010H3TAlpha]

Just talked to the dealer and it sounds like a bad BCM, truck won't even shift out of park now. Makes sense that the truck continued to have issues after changing the ignition switch, but what a pain. Will report back after they try the new BCM; thank goodness it happened in my driveway and not up in the mountains.

 

[alrock]

Hope that fixes it.

 

[2010H3TAlpha]

Thanks, me too. BCM seems to be bad so new one arrives on Friday. Crossing my fingers this works, this is the longest I've ever gone without my truck

 

[2010H3TAlpha]

New BCM is in. The truck will turn over once, then stops. When you go to turn the key again, nothing happens. Does that sound like a bad cam sensor?

 

[Traxx]

Any codes? Independent shop or a dealer? Independents don't usually fork out for the Tech2 scanner which you need for doing just about anything these days. Hopefully you told them you are paying for it to be fixed and not the shotgun throw parts at it til it works approach.

 

[2010H3TAlpha]

No codes, this is my local dealer of ~8 years and they've always taken good care of me. They discovered the 2nd BCM was also bad from the factory which was causing all the confusion. 3rd BCM arrives tomorrow, though a small part of me is expecting it to not be that easy given how crazy this has been.

 

[Traxx]

Have you ever had the fuse box off? Sometimes you can bend a pin on reinstall, I've done it, took a while to figure out what happened. After that I would start checking wiring, chewed/frayed etc, or the switch even though you replaced it.

 

[2010H3TAlpha]

Fuse box has never been out. We are starting to think there is a short somewhere because you can connect to the BCM (3rd one), but soon after it stops communicating with the Tech II. They did get it to start ONE TIME, but no luck since then. They have checked wiring everywhere, but haven't found anything obvious. Even GM corporate has no idea, which is not promising.

I am ready to dump this thing off a cliff.