Not starting.

[newjonwayne]

Took the intake off today to replace the intake gaskets and after I put it all back together and relanded the ground on the battery my 2007 Yukon 5.3 will not start. It has no interior lights, locks don’t work, gear indicator line doesn ’t work either. Some lights do light up on the garage cluster but there’s no actuation of the starter at all. Before I started on it, it started just fine.

 

[PG01]

Go back to the last thing you touched… battery cables.

 

[Geotrash]

Took the intake off today to replace the intake gaskets and after I put it all back together and relanded the ground on the battery my 2007 Yukon 5.3 will not start. It has no interior lights, locks don’t work, gear indicator line doesn ’t work either. Some lights do light up on the garage cluster but there’s no actuation of the starter at all. Before I started on it, it started just fine.

+1 to @PG01 above. Also check battery voltage. Are you sure you didn't remove any grounds in your work? Don't forget the braided ground cable on the firewall and the one on the front of the pax cylinder head. Did you remove the cable from the alternator to get the intake off? It runs right over the top of it.

 

[newjonwayne]

I’ve cleaned battery cables. Checked mega fuse, never touched the braided cable on driver side but it is tight on both ends, and I took off the alternator and the cable is back on. Still nothing

 

[PG01]

Seriously tho, your battery cables may look good on the ends but rotten in the middle… and you just moving them may have done it in.

 

[Doubeleive]

yep, your symptoms are "classic" power/ground related.

 

[newjonwayne]

Hooked my scanner up and looks like I may have a bad bcm. Engine, trans, and abs systems have a U0140 Lost communication with body control module. It’s showing it in history and current. I was pulling fuses so seeing how it’s current and they’re all back in and were good I’m thinking it’s a bcm issue.

 

[j91z28d1]

Hooked my scanner up and looks like I may have a bad bcm. Engine, trans, and abs systems have a U0140 Lost communication with body control module. It’s showing it in history and current. I was pulling fuses so seeing how it’s current and they’re all back in and were good I’m thinking it’s a bcm issue.

very rare you'd fry a bcm changing an intake, especially with the battery cable off.

before you go get one, check that those modules you can't talk to with the scanner have power and ground at the correct pins in their plugs.


this sounds like a missed ground wire somehow.

 

[wjburken]

Hooked my scanner up and looks like I may have a bad bcm. Engine, trans, and abs systems have a U0140 Lost communication with body control module. It’s showing it in history and current. I was pulling fuses so seeing how it’s current and they’re all back in and were good I’m thinking it’s a bcm issue.

Listen to what people here are telling you.

This for sure sounds like a broken/bad ground cable. You can check by putting the black side of a set of jumper cables from the negative post to the engine block.

 

[Charlie207]

Check the grounds on the front of the passenger cylinder head, back of the driver cylinder head (you said you checked), and down on the bottom of the block on the driver's side below/behind the power steering pump.

A loose connection on the front of the passenger cylinder head will prevent your systems from powering up.

 

[Doubeleive]

Hooked my scanner up and looks like I may have a bad bcm. Engine, trans, and abs systems have a U0140 Lost communication with body control module. It’s showing it in history and current. I was pulling fuses so seeing how it’s current and they’re all back in and were good I’m thinking it’s a bcm issue.

further evidence of a power problem, not indicative of a bad bcm
get a meter out and start checking voltages/grounds
start at the battery and work your way out section by section

 

[newjonwayne]

Listen to what people here are telling you.

This for sure sounds like a broken/bad ground cable. You can check by putting the black side of a set of jumper cables from the negative post to the engine block.

Cleaned up all the grounds I could find under the hood and bypassed the ground with jumper cables and still nothing. Tomorrow I’m taking the intake back off to make sure I haven’t pinched something.

 

[newjonwayne]

Had 2 friends help me look for a ground problem and nothing so today went to a wrecking yard and got a used bcm. Fired right up but now my air bag light is on and a new engine code popped up, crankshaft variation not learned

 

[wjburken]

Had 2 friends help me look for a ground problem and nothing so today went to a wrecking yard and got a used bcm. Fired right up but now my air bag light is on and a new engine code popped up, crankshaft variation not learned

Just for kicks, I’d put your other BCM back in and see what happens.

 

[j91z28d1]

Had 2 friends help me look for a ground problem and nothing so today went to a wrecking yard and got a used bcm. Fired right up but now my air bag light is on and a new engine code popped up, crankshaft variation not learned

that's wild.. I would love to know what killed the bcm.


the new one probably needs flashed to the car. few different ways to do it.

 

[newjonwayne]

that's wild.. I would love to know what killed the bcm.


the new one probably needs flashed to the car. few different ways to do it.

My thinking is it was bad before I ever started working on it. Was just waiting for no voltage to finally let go. I haven’t had any weird symptoms from it before but I definitely didn’t short anything while taking the negative off and back on. I’ve seen a couple vids of the same symptom but no cause.

And way to do it besides a dealer?

 

[newjonwayne]

Just for kicks, I’d put your other BCM back in and see what happens.

TBH I’m kinda curious myself. I don’t think it’ll fix the no start but I wonder if the airbag and extra faults I didn’t have before go away. Oh and my radio says locked and automatic lights no longer work but that’s programming most likely.

 

[Doubeleive]

My thinking is it was bad before I ever started working on it. Was just waiting for no voltage to finally let go. I haven’t had any weird symptoms from it before but I definitely didn’t short anything while taking the negative off and back on. I’ve seen a couple vids of the same symptom but no cause.

And way to do it besides a dealer?

you could program it yourself with techline connect/sps but you need a windows 10 pc/laptop and a mdi2, a mdi2 clone runs around $200 or so, maybe a little more. The programming fee is $45 for 2 years of programming. only for 1 vin.