SOLVED - Big 3 upgrade, EVERY warning light on immediately after.

[Tyrant]

I appreciate the responses thus far.

I replaced 3 wires, routed them exactly as they were from the factory (with the sole exception of the fact that I reversed my battery's direction for ease of access), and left the smaller secondary ground wire intact. I have continuity where I should, voltage measures as it should, and I've re-checked each of the 3 repeatedly just to be thorough.

This is why I opted to wait before adding additional grounds or tackling the alternator to distribution block wiring; I wanted to eliminate excess variables in the event that something went wrong.

Unless the decreased resistance from replacing extremely corroded wiring directly damaged something, this shouldn't be the problem. It's frustrating, because I've done this a dozen or so times with other vehicles, and have even made full wire harnesses for street and track vehicles in the past...

 

[Tyrant]

 

[Tyrant]

Only the one, although the factory routing of the wiring is pretty straight-forward.

3 wires of varying length were replaced, routed in identical fashion to the corroded 4 awg wire that you see in this last photo.

 

[Tyrant]

I didn't get "creative" with the routing; I plan to add additional grounds from the block to the body on both sides of the bay, however I elected not to change anything but the diameter of the wire initially in the event that something like this occurred. I'm pretty conservative with my modifications, experience has taught me not to tackle more than 1 project at a time.

 

[Tyrant]

I'm currently working through the TSB from GM (08-07-30-021G), chasing down the various pins and grounds, cleaning contacts and re-applying dielectric grease where necessary. I'll replace all of the J-Case fuses just in case one of them has failed without obviously appearing to... I replaced every mini blade fuse proactively when this started, since I had a few hundred of them on hand to begin with.

 

[CaptainAmerica1]

Don’t get me wrong. This problem wasn’t there till you messed with it. Therefore whatever you messed with CAUSED said problem. It’s frustrating I get it. Your overlooking the obvious.

 

[Tyrant]

I pulled every connector and ground from the rear doors to the rear bumper and wire brushed contact points, then slathered dielectric grease on the connector for the fuel pump control module. The CEL is gone, it revs to redline in all gears and shifts perfectly - the U0109 code is still present after clearing, which is odd.

 

[iamdub]

I did pull and replace each fuse of the mini blade fuses with new ones just to be safe, while I switched the J-case fuses with others (known working) to test them. I didn't replace the J-case fuses outright, but I am thinking it couldn't hurt at this point...

Well, damn.

 

[Tyrant]

Don’t get me wrong. This problem wasn’t there till you messed with it. Therefore whatever you messed with CAUSED said problem. It’s frustrating I get it. Your overlooking the obvious.

I get it, the logic follows - the problem is, the 3 wires I replaced would cause EVERYTHING to fail if any 1 of the 3 wasn't functioning.

I could rip out the 1/0 wire and replace it with extraordinarily over priced "factory" 4 awg and it wouldn't magically solve anything, because current is flowing and voltage is ~12 when off and ~14.2-14.7 at idle, while resistance is negligible.

It's stupid because power is so simple - if either of the 2 charge or 1 ground wires weren't functioning, it wouldn't start (let alone run and drive for 300+ miles).

I do have a few more connectors to blow out and grease; the previous owner ripped the splash shields out, so they're pretty dusty and it can't hurt to try them before I throw the new shields on.

 

[CaptainAmerica1]

Ok. Good luck my man.

 

[Tyrant]

All lights work, audio works, power pedal adjust works, trailer functions work, overhead DVD player works, backup sensors work, and literally EVERYTHING but the ABS/Traction control/4 low is functioning.

It's popping a TCCM error code, which (per the forums) typically leads to a bad switch (mine illuminates AND switches successfully from 2 high to 4 high and back) or the TCCM itself...

When I get home this week, I'll run to another shop and try a different scantool. If a third brand doesn't read it, I guess I'll start over from scratch.

 

[iamdub]

I pulled every connector and ground from the rear doors to the rear bumper and wire brushed contact points, then slathered dielectric grease on the connector for the fuel pump control module. The CEL is gone, it revs to redline in all gears and shifts perfectly - the U0109 code is still present after clearing, which is odd.

Well, damn, again.

 

[Tyrant]

Ok. Good luck my man.

I appreciate you taking the time, I mean it. The first thing I checked was those 3 wires, I did voltage checks at each and and measured resistance from the fuse box to the battery, as well as the ground to battery and starter to battery.

Continuity checks out and resistance was minimal... I even disconnected the 10g ground behind the bumper and wire brushed it, despite never touching that before the 1/0 install.

 

[iamdub]

All lights work, audio works, power pedal adjust works, trailer functions work, overhead DVD player works, backup sensors work, and literally EVERYTHING but the ABS/Traction control/4 low is functioning.

It's popping a TCCM error code, which (per the forums) typically leads to a bad switch (mine illuminates AND switches successfully from 2 high to 4 high and back) or the TCCM itself...

When I get home this week, I'll run to another shop and try a different scantool. If a third brand doesn't read it, I guess I'll start over from scratch.

I'm still stuck on a module being affected by the power loss and restoration. Any chance you might have disconnected the battery (positive or negative) with the key on? Any chance you might have, even very quickly and/or very lightly, brushed a negative cable terminal to the positive post or a positive cable terminal to the negative post?

 

[Tyrant]

Are these systems extremely sensitive to voltage changes? The only other impact I can think of is that the voltage seems to be more consistent on long drives. Prior to the wire job, it was ~14 on the gauge and it sits at a steady 14.5 while driving now. Actually measures out to 14.2-14.7 with a voltmeter.

 

[George B]

With the codes you have and the level of confidence in your electrical work I would be suspecting a module issue. It wouldn’t be the first time someone has had “U” codes after battery work on here. It would be nice to have a scan tool that could ping each module and confirm a handshake and that they were awake.

 

[George B]

I'm still stuck on a module being affected by the power loss and restoration. Any chance you might have disconnected the battery (positive or negative) with the key on? Any chance you might have, even very quickly and/or very lightly, brushed a negative cable terminal to the positive post or a positive cable terminal to the negative post?

You beat me to it!

 

[Tyrant]

I'm still stuck on a module being affected by the power loss and restoration. Any chance you might have disconnected the battery (positive or negative) with the key on? Any chance you might have, even very quickly and/or very lightly, brushed a negative cable terminal to the positive post or a positive cable terminal to the negative post?

That's possible... I'm damned careful and certainly didn't notice any inadvertent shorts. I feel like a short of that nature would've blown a fuse somewhere, but the only thing I found in the entire vehicle was the trailer wiring fuse.

If that happened, it completely slipped by me, and I ripped the battery out before I touched anything else.

 

[Tyrant]

Some of my exterior lights (previous owner ran overheard lights on the roof) do stay illuminated for long after I pull the key and close the doors. I do also keep a dash cam hardwired in the vehicle, I may have left that plugged into 12v power when I pulled the battery...

 

[Tyrant]

If I caused a short by failing to unplug my dash cam, I'd be kicking my own butt for months. I think you guys are right about the modules, I'm just afraid to bite the bullet and go through the hassle of replacing them, only to program new ones and run the risk of it being something simpler.

I'm really hoping that I'm just missing something obvious, but I've tried to K.I.S.S. and work my way from simplest to most complicated...