Big 3 upgrade, EVERY warning light on immediately after.

Tyrant

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Hello all; this will be a bit of a lengthy post, so I'll try to keep it concise.

'08 Suburban, listed in my signature. After some rough starts this past winter (Wyoming, -20° F), I decided to tackle the big 3 and go with a better battery. I immediately swapped the battery out for an appropriately sized AGM from Interstate - No problems whatsoever thus far. Installed back in February.

This month, I preemptively tackled the charging system in preparation for an audio upgrade.

Parts list:
- 1/0 AWG pure copper wire (battery wire, marine rated), which I then sleeved with a high temp sleeve (think tech flex).
- Tinned copper lugs, crimped w/ a hydraulic crimper and covered with adhesive lined shrink tubing at all joints.
- "Military style battery terminals" (Multiple attachment points, ideal for my goals)

Process:
1. I replaced both of the factory "hot" wires from the battery with 1/0 AWG, attached to the factory locations (starter and factory fused distribution block), trimmed the cover for the distribution block for adequate coverage and a snug fit.

2. I replaced the factory ground wire (large diameter) that runs directly to the block, yet decided to re-use the smaller wire that runs down by the front end. I replaced what I assume to be the voltage/current sensor in the factory location along this same ground wire.

3. Due to prior experiences, I tend to tackle these projects incrementally, so I did NOT elect to add additional grounding points yet so that I could tackle issues without introducing extra variables. After I sort this out, I'll be adding 2 additional grounds and replacing the distribution block to alternator wire w/ an additional 1/0 run.

Result:
WAY smoother starts in warm and cold weather, no odd dimming issues with lights or audio system use, and consistent voltage hovering right at 14.5 (per the gauge, corroborated w/ my scantool).

Problem:
EVERY dash light came on after the wiring was replaced. ABS, brake warning light, CEL, Traction control, and 4WD Service.

I have used 2 scantools (1 bluetooth model and 1 INNOVA 5210 v1 bi-directional) to assess and clear codes, to no avail. The CEL code clears, then returns shortly after... The others immediately return.

Codes:
U0102 - "Lost Communication w/ TCCM" (4WD) - Important note, ALL 4WD options work as expected, with the exception of 4 LOW. The rotary dial illuminates and it engages consistently as it always has.

U0109 - "Lost Communication w/ Fuel Pump Control Module" - This is intermittent, the truck starts and runs like a champ every time. I DID notice that there appears to be a missing relay in the primary fuse panel, which is listed as "FUEL PUMP" on the diagram - it is sandwiched between 31/33 and PRK LAMP, this has never been present so long as I have owned the vehicle.

ABS would not read with either scanner. After seeing the aforementioned codes, I cleared them multiple times and have checked every single fuse within the vehicle. The only fuse that was blown was the trailer pigtail for towing; I replaced it proactively, even though I seldom tow with this.

It has run reliably and driven as usual for ~1 week, approximately 250 miles. I did notice yesterday, while entering an on-ramp to an 80 MPH Interstate, that it would not rev beyond 2,000 RPMs in 4th gear, and wouldn't downshift on full throttle. I suspect that this is a different issue, as it only manifested the one time. There is still plenty of torque and it accelerates fine otherwise.

Thanks for reading my long-winded post; I'm hopeful that somebody will have some suggestions for me. I tackled all of the troubleshooting that I felt was prudent before throwing up a post.
 

Just Fishing

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Hello all; this will be a bit of a lengthy post, so I'll try to keep it concise.

'08 Suburban, listed in my signature. After some rough starts this past winter (Wyoming, -20° F), I decided to tackle the big 3 and go with a better battery. I immediately swapped the battery out for an appropriately sized AGM from Interstate - No problems whatsoever thus far. Installed back in February.

This month, I preemptively tackled the charging system in preparation for an audio upgrade.

Parts list:
- 1/0 AWG pure copper wire (battery wire, marine rated), which I then sleeved with a high temp sleeve (think tech flex).
- Tinned copper lugs, crimped w/ a hydraulic crimper and covered with adhesive lined shrink tubing at all joints.
- "Military style battery terminals" (Multiple attachment points, ideal for my goals)

Process:
1. I replaced both of the factory "hot" wires from the battery with 1/0 AWG, attached to the factory locations (starter and factory fused distribution block), trimmed the cover for the distribution block for adequate coverage and a snug fit.

2. I replaced the factory ground wire (large diameter) that runs directly to the block, yet decided to re-use the smaller wire that runs down by the front end. I replaced what I assume to be the voltage/current sensor in the factory location along this same ground wire.

3. Due to prior experiences, I tend to tackle these projects incrementally, so I did NOT elect to add additional grounding points yet so that I could tackle issues without introducing extra variables. After I sort this out, I'll be adding 2 additional grounds and replacing the distribution block to alternator wire w/ an additional 1/0 run.

Result:
WAY smoother starts in warm and cold weather, no odd dimming issues with lights or audio system use, and consistent voltage hovering right at 14.5 (per the gauge, corroborated w/ my scantool).

Problem:
EVERY dash light came on after the wiring was replaced. ABS, brake warning light, CEL, Traction control, and 4WD Service.

I have used 2 scantools (1 bluetooth model and 1 INNOVA 5210 v1 bi-directional) to assess and clear codes, to no avail. The CEL code clears, then returns shortly after... The others immediately return.

Codes:
U0102 - "Lost Communication w/ TCCM" (4WD) - Important note, ALL 4WD options work as expected, with the exception of 4 LOW. The rotary dial illuminates and it engages consistently as it always has.

U0109 - "Lost Communication w/ Fuel Pump Control Module" - This is intermittent, the truck starts and runs like a champ every time. I DID notice that there appears to be a missing relay in the primary fuse panel, which is listed as "FUEL PUMP" on the diagram - it is sandwiched between 31/33 and PRK LAMP, this has never been present so long as I have owned the vehicle.

ABS would not read with either scanner. After seeing the aforementioned codes, I cleared them multiple times and have checked every single fuse within the vehicle. The only fuse that was blown was the trailer pigtail for towing; I replaced it proactively, even though I seldom tow with this.

It has run reliably and driven as usual for ~1 week, approximately 250 miles. I did notice yesterday, while entering an on-ramp to an 80 MPH Interstate, that it would not rev beyond 2,000 RPMs in 4th gear, and wouldn't downshift on full throttle. I suspect that this is a different issue, as it only manifested the one time. There is still plenty of torque and it accelerates fine otherwise.

Thanks for reading my long-winded post; I'm hopeful that somebody will have some suggestions for me. I tackled all of the troubleshooting that I felt was prudent before throwing up a post.

You did this with the battery disconnected I assume?
And you went through your grounds at the same time?

To me this sounds like a ground issue, or it's a bad or missing connection somewhere in the upgraded wiring.
 
OP
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Tyrant

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Fair question, but ABSOLUTELY. I pulled the battery completely, as I do with all "big 3" upgrades. It's absolutely acting like either the ABS module failed or one of the wheel speed sensors did... What blows me away is that it didn't happen while driving or anything, but on my first startup after the upgrade.

All of the components are top quality, I personally aligned and crimped every single joint, and it runs like a champ. I hand adjusted every wire so that it wouldn't have any linear or torsional tension on it once crimped, so it won't be inclined to flex over time...

It didn't give me any grief after I fed an additional 1/0 wire into the cabin for my amplifiers, either. Voltage is great, 4WD / Auto / 2 high all work properly, and it fires up immediately when cranked.
 
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Tyrant

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I even avoided adding supplemental grounds early on, in the event that something did happen... These newer vehicles are a PITA, makes me miss my old 80s/90s beaters.
 
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Tyrant

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On a related note - I did replace the pads/rotors 2 days ago (issues were already present), checked each hub's sensor visually and shook each wheel at 3/9 and 6/12 o'clock to feel for hub play. Nothing...
 

Joseph Garcia

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Did you check to see if there is another electrical connector attached to the frame into which the hub sensor wire is connected? I am not very familiar with the front end wiring, but on the rear there is a connector that I alluded to, and it is very easy for it to become disconnected.
 
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Tyrant

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I'll take a look, but I can't even get a code from either of these modules... So I'm unfortunately forced to look at all of them.
 
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Tyrant

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I dug through everything this weekend; checked all 4 corners and didn't see anything that stuck out to me. I did pull up some TSBs for the vehicle, apparently all of these symptoms popped up frequently enough that GM felt the need to put one out...

I didn't mess with the impacted modules at all, but logic suggests that the TSB is related to the issue. The odds of each of these systems failing simultaneously while parked are pretty slim... I bought some dielectric grease and I plan to inspect and slather every junction related to these systems thoroughly, while roughing up bare metal and re-seating the related grounds. If this doesn't do something, then I'm absolutely stumped...

4WD low isn't working, but 2 high/auto/4 high are and everything else seems good. It is giving me grief when accelerating hard in drive, doesn't want to rev past 2,000. Other gears are unaffected and it shifts just fine...
 

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