George B
¯\_(ツ)_/¯
Before I loaded the parts cannon full of modules I would look for somone with a tech2 and dig into troubleshooting the CANbus.
SOLVED - Big 3 upgrade, EVERY warning light on immediately after.
- Thread starter Tyrant
- Start date
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iamdub
Full Access Member
With these rigs having RVC, the components should be perfectly fine experiencing 12-14.xx volts.
iamdub
Full Access Member
Modules go into "sleep" and "awake" modes. I'm wondering if the camera, presenting a slight draw, was keeping a module (BCM?) active/awake.
I'm wondering if a module just had a rude awakening when the power was restored with extra equipment, such as your camera, was connected to it. Maybe disconnect anything aftermarket like that (lights can stay as long as their switch is off), let it sit for a while in hopes to put the modules to sleep then disconnect the negative battery cable. Let it sit for awhile then reconnect the battery cable. Test from there.
Thank you guys for sticking this out with me; I commute 170 miles from home, so I've been gone this past week. I'll be home tomorrow, so I'll find a local shop with a Tech 2 or bite the bullet and order one.
After blowing the dust out of the various connectors and slathering them with dielectric grease yesterday, the CEL disappeared on me. It's still throwing a U0109 code, despite clearing it twice, but it revs hard to redline now in both 2 high and 4 high, and shifts through all of the gears again.
That cut one issue, thankfully. I still don't understand why I would have 4 high and not 4 low, but the U0102 is really stumping me. I didn't have 4wd issues before, but I have used both of these scantools with the vehicle in the past and they never popped that code previously.
After blowing the dust out of the various connectors and slathering them with dielectric grease yesterday, the CEL disappeared on me. It's still throwing a U0109 code, despite clearing it twice, but it revs hard to redline now in both 2 high and 4 high, and shifts through all of the gears again.
That cut one issue, thankfully. I still don't understand why I would have 4 high and not 4 low, but the U0102 is really stumping me. I didn't have 4wd issues before, but I have used both of these scantools with the vehicle in the past and they never popped that code previously.
yeah a ground wire from the battery to the chassis (under the radiator) this wire is connected still ?
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George B
¯\_(ツ)_/¯
There are two grounds landed on the frame under the core support. one comes from the negative battery terminal and the other comes from elsewhere. I believe the fans are included in the second one.
HACK BLOCK
Full Access Member
my brother had the U0102 code after getting some work done and in his case it was a grounding issue. he had returned his tahoe to the shop that did the original work and they were able to fix it
I snapped up a Tech2 and I'll be trying to diagnose the canbus issue directly; I pulled the secondary ground behind the bumper just to be safe, wire brushed it and re-attached it. I also replaced every J case fuse and every mini blade fuse in the UBEC with new Littelfuse replacements just to be safe. I have a pile of extras now, too, and I cleaned the dust off with compressed air.
The engine seems to go into limp mode every other drive, refusing to rev beyond 2K in drive or accelerate hard... The next time, it'll pull to redline without issue. I'm now catching a cylinder 8 misfire on full throttle pulls as well, so plug wires are on the list now as well.
I suspect that I shorted something and fried one or more of the modules during the 1/0 install... I'm extremely careful and can't imagine doing it, but it's the only logical conclusion I can draw so far. Hopefully the Tech2 helps me to narrow that down...
The engine seems to go into limp mode every other drive, refusing to rev beyond 2K in drive or accelerate hard... The next time, it'll pull to redline without issue. I'm now catching a cylinder 8 misfire on full throttle pulls as well, so plug wires are on the list now as well.
I suspect that I shorted something and fried one or more of the modules during the 1/0 install... I'm extremely careful and can't imagine doing it, but it's the only logical conclusion I can draw so far. Hopefully the Tech2 helps me to narrow that down...
Alright, the Tech2 emulator is extraordinarily helpful.
It hasn't given me any magical solutions, however it has identified and communicated properly with every system except for the TCCM (T-Case CM) and FPCM (Fuel Pump CM).
It's showing the expected failure to communicate for the Bose Amp (removed) and other features that the vehicle never came equipped with (ie electronic suspension/electronic lift gate).
It hasn't given me any magical solutions, however it has identified and communicated properly with every system except for the TCCM (T-Case CM) and FPCM (Fuel Pump CM).
It's showing the expected failure to communicate for the Bose Amp (removed) and other features that the vehicle never came equipped with (ie electronic suspension/electronic lift gate).
There is no aux bcm, mine does the same thing when queried, it may have been some special option at some point or only apply's to some kind of special optional equipment, who knows.
all of the other stuff may be on the same harness, you might start looking for a broken wire or chaffed wire? or maybe the bcm got cooked, just speculating
Thank you for that, I've been chasing that rabbit hole and it was right up there with the non existent fuel pump fuse/relay fiasco for the 2008 model year!
I've inspected everything that's readily visible, 100% of the wires that I worked with when I changed the battery cables out as well. I've also cleaned and re-seated every ground beneath the body/frame and gone over all quick connects with dielectric grease.
I'm to the point where I'll need to pull the UBEC and the I/P panels, check every single module directly, and re-assemble with dielectric grease now. The Tech2 diagnostic was my last ditch effort to avoid that, since I didn't want to introduce more variables that could exacerbate my problems...
I've inspected everything that's readily visible, 100% of the wires that I worked with when I changed the battery cables out as well. I've also cleaned and re-seated every ground beneath the body/frame and gone over all quick connects with dielectric grease.
I'm to the point where I'll need to pull the UBEC and the I/P panels, check every single module directly, and re-assemble with dielectric grease now. The Tech2 diagnostic was my last ditch effort to avoid that, since I didn't want to introduce more variables that could exacerbate my problems...
The BCM would affect all of these, but I'm hesitant to suspect it outright when everything else works... It's a complex system, but I can't help but feel that it's something specific to the wheel speed/hall sensors.
What's frustrating is that those should populate an error other than a failure to communicate, which is what makes me think you're right on the money with the BCM.
What's frustrating is that those should populate an error other than a failure to communicate, which is what makes me think you're right on the money with the BCM.
a used bcm is not expensive, it's just a mild headache but if you throw a used one in there and program it then it's at least less hassle than chasing wires.
I see in your photos it has no communication with the rear hatch, memory seat, heated seat, etc, so either you don't have any of those? or there is a serious problem
BCM Aux is only on Export models, like European-market Escalades with Rear Fog Lights.
I don't have those, thankfully; it's a moderately optioned LT, I added front heated seats myself but they're a simple relay/switched setup and didn't rely on any other systems.
