UO107 & P1258 Errors, Yukon Died....Help !

[AA1PR]

UO107 & P1258 Errors, Yukon Died....Help !

all was well, was coming home the back way, hit a bump in the dirt road & the rig died
I'm getting these 2 errorrs UO107 & P1258
UO107 ~ lost communication with throttle actuator control module
P1258 ~ engine metal over temperature protection
the DIC is telling me that engine overheated, reduced engine power, & engine coolant hot
when this happened the temp gauge pegged to the rightabove 260 & remains there as long as the key is turned on
& now even an hour later it still does this ?
however I can grab the hoses & touch the radiator without being burnt when it happened
got plenty of DC Voltage but starter wont engage or anything

HELP please

thinking I need an older model & sell this one off

[ErikSS]

Do you have a scanner to read the actual temperature reading, or just the dash gauge? They are OFTEN very different. If you don't think it was as hot as the gauge says, maybe you could start by unplugging the temperature sensor and monitor the change. If there is no change, perhaps the sensor went bad.

[AA1PR]

Sir, Thanks

I just have a cheap OBDII scanner but no temp feature I know of

http://www.youtube.com/watch?v=gtK4oajc ... ZXqzQZlnOg

I too was thinking the temp sensor went bad

we disconnected it & still nothing, cant get the codes to erase

last month I replaced the waterpump, flushed the system & new hoses, thermostat etc now this

from some research if the unit has gotten wet it is prone to fail, which makes no sense if you drive in the rain per se

however when my son get here we learned the negative cable off of the battery was almost falling off, so maybe that triggered the issue

a lot of what I read online tonight mentioned B+ failure, so maybe B- failure could do the same

we tried to reset the codes but that didnt work

thinking of pulling both battery cables & letting it sit for a 1/2 hour to see if that will reset things

wish me luck & hoping the rain stops so we can work on this...

[AA1PR]

negative cable on battery was almost falling off, not sure if this contributed to my issue as I said before
my son replaced the coolant temp sensor & still no go
however the codes did clear UGH
even tried to disconnect the battery for 10 minutes to see what that woudl do & nothing
when we try to start it we can hear the throttle position unit click, but no starter spin etc
checked all the fuses & wires, sprayed electrical contact cleaner in all the connectors we could find & worked those on & off
helpless on this one
any ideas I'm game

[Bacnbit]

This may get interesting for you with out proper scan tools and meters.
Some may say Throttle body is junk which it may be having seen alot of them being replaced over the years.
But TAC module needs to Communicate with the PCM. Which the two have there own line so sometimes that makes testing alittle easier. IE wire integrity, connections etc. But I would think it would still Run. I am sure the No start Dead condition is related to the P1258 (overtemp code). this code Disables fuel system. My first thought would be why is the gauge pegged when cold?? I would try a gauge sweep test first see if Cluster is FUBAR then go onto connections, PCM wireing etc. (Gauge pegged First thought grounded Something) Like I said I think when you find the problem it may not be a huge issue but time consumming and head scratching.
Good Luck.

[AA1PR]

Bacnbit thanks, we replaced the temp sensor yesterday & the P1258 is now gone

Ok so here is the old temp sensor will check it for ohms cold, boil it & then recheck



bacnbit the temp gauge in the dash has returned to normal after the new sensor was installed

on another forum someone suggested that I look to see if the ground was broken off, common error

couldnt find any green wire under there:

passenger side



drivers side



something has the rig in safety mode it seems

& tested the fuel rail at the factory test point & nothing



only bad fuse I found was for my left trailer light, kinda knew that since last time I towed my M416 trailer it didnt work...



disconnected positive lead on battery for 15 minutes if not more, reset codes before & after, still getting UO107 failure to communicate with TAC

not sure if thats my problem, couldnt get the plug apart to see if I had the 5v on the required wires & couldnt get on the ground (disabled) to check the battery leads running to the starter either referencing this online article ~ http://easyautodiagnostics.com/gm/4.8L- ... tle-body-1

called 2 shops & no replies yet

[Bacnbit]

Just curious and this sounds really stupid. Did you pull the ECM and The BCM fuses out for 10 minutes Key on yet. I just did a timing chain Job on a newer GM 2.4 Scan tool and battery cable methods of clearing would not function for some reason. Pulled ecm,bcm,tcm fuses Key on engine off, All cleared vehicle Ran beautiful after that. It would not clear the codes from prior to the chain jumping for some reason. Just an Idea.

[AA1PR]

NO I never heard of that but will try it, nothing to lose at this point

& if I can get it fixed before it goes into the shop all the better

cleaned up the grounds behind the drivers tire on the side of the frame this afternoon too, since my mechanic thought I had a bad ground

took them off to give a good cleaning


got all the rust off



& back on


now he thinks I have a broken "+" wire somewhere

at this point he can fix it, he has the computer that will hopefully show whats going on

[AA1PR]

its at the mechanics

he was going to replace the ECM

not sure where he's at with it, I called at closing with no answer....

[AA1PR]

the mechanic called last nite, he put in a used ECM from the salvage yard

it learned the system, starts & stops

however it wont move, he says when you try to move it, it feels like its stuck in OD & wants to slip

so back onto the computer sometime today

hopefully he didnt ruin my transmission by moving it in & out of the shop so many time

[ErikSS]

Does your model have a separate TCM? Transmission Control Module. Perhaps the ECM and the TCM aren't communicating. I would think If it wouldn't start with the old ECM and it does with a used one.... you've identified the root problem. Just gotta iron out the details.

[AA1PR]

the mechanic called me this afternoon while I was in route for my back procedure


the ECM is wrong for my vehicle, he claims my Yukon has an upgraded transmission package & needs the other model of ECM
which will hopefully be here before the weekend
he made metnion that is was throwing the speed sensors off
& how can my transmission be upgraded I have to ask too ?

[ErikSS]

The only real "upgrade" that would affect speed sensors is if you have a 4l80e instead of a 4l60e. I thought all 5.3L came with the 4l60e. I was told they only used the 4l80e with the 6.0l in 2500/3500 only.

[AA1PR]

not sure at this point

members on another forum think he blowing smoke.....

though my RPO code shows a 4160E

[ErikSS]

The blowing smoke theory makes sense. Its very expensive to upgrade to an 80. The 4L60/65/70E use the same speed sensors. The wrong ECM does still make sense to me though.

[AA1PR]

Thanks

my original thought was if you had the VIN, how in the world could you order the wrong part

hopefully I'll get it back tomorrow

its been too long with out her

[AA1PR]

I want to thank you all for the help & easing my worries
it was the ECM after all

[ErikSS]

I'm glad they got it running for you!

[AA1PR]

I'm glad they got it running for you!

Me Too !

in all seriousness I'm disabled & without it I'm stranded, so you can see its importance