Yukon Denali issue
- Thread starter DGMCTRUCK
- Start date
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hmm so just looking ******(you can't type quick ly here? odd word to sensor lol) , I would disregard all the U codes, the network went down forsure. that's about all you can learn from those, and the ones requesting the mil light on. those are generic. the individual modules cants turn on the mil light themselves, they have to request the ecm to do it for them. that's all just redundant and doesn't say much.
in the engine data, few things I see. it looks like your were diving along and the 12v battery voltage was 11.9. that's very low like truck not running key on low. should be high 13s up to 15s sometimes.
it shows rpm 0, the maf shows zero airflow, mph and spark advances all 0. like the engine wasn't running when it captured that freeze frame data. I'm not sure exactly what gust means, but if you were above 30mph the engine should have been running.
where it shows 8 dtcs on the transmission control module, I'm sure one will be a U for communication and one for mil request. but can you read the other 6 codes? they might be more specific. same with the ecm codes. it says 4, maybe there's 2 of them useful?
curious if you've tried clearing theses and they reset or is this the first batch from what it locked up the wheels.
in the engine data, few things I see. it looks like your were diving along and the 12v battery voltage was 11.9. that's very low like truck not running key on low. should be high 13s up to 15s sometimes.
it shows rpm 0, the maf shows zero airflow, mph and spark advances all 0. like the engine wasn't running when it captured that freeze frame data. I'm not sure exactly what gust means, but if you were above 30mph the engine should have been running.
where it shows 8 dtcs on the transmission control module, I'm sure one will be a U for communication and one for mil request. but can you read the other 6 codes? they might be more specific. same with the ecm codes. it says 4, maybe there's 2 of them useful?
curious if you've tried clearing theses and they reset or is this the first batch from what it locked up the wheels.
I'm over 165k on mine and the tranny fluid sample tests good. so it would be horrible luck for your tranny to blow up at 140k.
so I'll attach what my software says for limp mode for these trucks. I'm hoping you have one of these P code dtc's in your ecm. that would help give some direction as to why it's in limp.
and what the tranny defuals to when it's in limp mode.
hopefully those arw readable. I'm just on my phone and can't tell on my end.
ahh, so that's helpful. I was thinking this was from the first event. so we know the Communications Network is still down, so that's not intermittent or one time thing.
since you have that replacement module coming. I hope that fixes it.
there's actually 2 networks, I high speed and a low speed. do you have a ohm meter?
my guess is high speed is down, since you can still see some info from modules besides the ecm. I'd be curious if you can retrieve it those 4 ecm codes and 8 tcm codes.
edit, the 11.9v probably means it sets the codes before the engine even started, at first key on.
so here's that video on the basics of can bus practical troubleshooting. if you have a volt/ohm meter. it would be interesting if you can test for the ohm across the can terminals in the obd2 port. what would tell you if the system is intact.
I know that sounds bad, but small upside is it's not intermittent. which makes things even harder to find. atleast at this point of you fix it. you know it's fixed.
does the scanner turn on? like it's getting 12v power from the port but can't connect? if so, that's definitely the can bus network down. or the scanner won't turn on. it might be a fuse.
at this point, all I can say fingers crossed it's that rear module like in the video. if not, you might have to get a ohm meter and first step is look for the 60ohms across the 2 pins of the network.
if you take it to a shop, make sure you ask if they have someone good with can bus trouble shooting and is willing to work in hybrids. I've seen stories of towing trucks to places and then finding out they wouldn't touch it.
this tsb shows some of the locations of wiring harnesses routing issues. you might take a look at them for damage in the mean time.
petethepug
Michael
Whoa, wasn’t expecting the latest post to shortcut to the first post edited that you sold it. The 11+ hybrid are loved here in SoCal.
With the high city milage and $2+ a gal savings on e85, there’s still no other V8 full size SUV/Luxo wagon that compares.
Pretty sure the current owners must be the engineers who designed them and know all their quirks.
most likely a few pins got pushed out on the transmission this happens VERY often on GMs that would take the CAN bus down they got a GOOD DEAL what ever they bought it for
