Hi. 43 year old woman with a little more knowledge than the average Joe on scanners and codes and basic troubleshooting but I tend to get dismissed or talked in circles at the shop. I'm not trying to lump everyone together or create any stereotype battle here. It simply is what it is with my personal experience. I like to know what I'm potentially getting into before I arrive so here I am for open discussion. Any help and education here appreciated. As soon as I mention electrical issues, shops tend to shy away or dismiss me but I'm sure that has nothing to do with me being a woman. I believe that's pretty common and it takes the right place with the right knowledge.
Just bought 2002 trailblazer. 4.2l inline 6. 4wd. The basic LS trim if that matters.
I use a bluedriver scanner. Since owning it, I've had various lost communication codes in different modules that I'm having a hard time figuring out what a good starting point is. U1000 is a more recent one with the data link malfunction description after already receiving intermittent communication loss codes. Here are some examples.
U1000 class 2 data link malfunction
U1041 brake/traction control
U1064 body multiple control system
U1152 hvac
When I first bought it, I had a ton of b codes along with a u1064 under the category header of body control module. I opened the panel on the dash and the fuse box under the rear seat and made sure all connections to anything I had access to seemed tight. Checked fuses, relays. Etc. Earlier, I had p0340 and I'll have the shop look at the camshaft sensor but in the meantime, I saw a thick coating of dirty oil all around the connector and I wiped that off and that code seems to have disappeared for now. While under the hood, any wiring I could reach was checked to make sure connections were tight to the best of my ability. I didn't see anything majorly suspicious as far as frayed wires or things that weren't connected.
After that, all the b codes went away. I haven't seen them again but the u codes show up as history codes typically and the part that confuses me is sometimes the code will be under right rear door module and other times it's under door/gate module and other times it's under body control module. u1000 is usually under the header powertrain. When I refer to headers, I mean in the blue driver app, there is what I call a header or description of area and the code is listed underneath it. The code seems to bounce around and change with the same code u1064 appearing under them and u1000 remaining under powertrain until today it showed up under powertrain and something called shared address module code. Moments ago, u1152 showed up after losing ability to accelerate at stoplight. Related? It is listed under door/gate module code in my bluedriver app.
I do have all sorts of weird things going on but I'm mainly trying to understand what all of this loss of communication means when it comes to the various areas they show up in. I don't understand why u1064 will show up as a history code under the header right rear door module and under the header door/gate module code but then later one of those will drop off. I also don't know for sure that everything is scanning correctly. I know there are a certain amount of tests that the engine computers do before history codes will fall off but sometimes it feels like the scan will say completed but it's not really showing me everything and then the next time I will see some of the history codes and they will be gone the next time and new history codes will be shown. It seems to be the same codes right now cycling through being listed under different modules and areas. For example, u1041 will sometimes show up as an airbag code under that airbag header and later it's showing up with the airbag information under the header for body control module. Sometimes they show up together under both at the same time.
Am I looking at something like a ground somewhere or am I looking at all of the various modules and systems all failing at the same time? BCM, door/gate, right rear door module as well as brake traction system, hvac system etc etc? I did read somewhere it could be pins(?) needing to be checked on the serial data bus connector inside the dash on drivers side (I apologize if that's not what it's really called but hopefully someone will know what I mean).
I've seen YouTube videos where they say it's a bad bcm. I've seen forums state it's actually the ecm. Everything I find involves a bunch of reading without the ability to ask questions so I've come here. I can warn you in advance that I will likely have many.
Elizabeth
Just bought 2002 trailblazer. 4.2l inline 6. 4wd. The basic LS trim if that matters.
I use a bluedriver scanner. Since owning it, I've had various lost communication codes in different modules that I'm having a hard time figuring out what a good starting point is. U1000 is a more recent one with the data link malfunction description after already receiving intermittent communication loss codes. Here are some examples.
U1000 class 2 data link malfunction
U1041 brake/traction control
U1064 body multiple control system
U1152 hvac
When I first bought it, I had a ton of b codes along with a u1064 under the category header of body control module. I opened the panel on the dash and the fuse box under the rear seat and made sure all connections to anything I had access to seemed tight. Checked fuses, relays. Etc. Earlier, I had p0340 and I'll have the shop look at the camshaft sensor but in the meantime, I saw a thick coating of dirty oil all around the connector and I wiped that off and that code seems to have disappeared for now. While under the hood, any wiring I could reach was checked to make sure connections were tight to the best of my ability. I didn't see anything majorly suspicious as far as frayed wires or things that weren't connected.
After that, all the b codes went away. I haven't seen them again but the u codes show up as history codes typically and the part that confuses me is sometimes the code will be under right rear door module and other times it's under door/gate module and other times it's under body control module. u1000 is usually under the header powertrain. When I refer to headers, I mean in the blue driver app, there is what I call a header or description of area and the code is listed underneath it. The code seems to bounce around and change with the same code u1064 appearing under them and u1000 remaining under powertrain until today it showed up under powertrain and something called shared address module code. Moments ago, u1152 showed up after losing ability to accelerate at stoplight. Related? It is listed under door/gate module code in my bluedriver app.
I do have all sorts of weird things going on but I'm mainly trying to understand what all of this loss of communication means when it comes to the various areas they show up in. I don't understand why u1064 will show up as a history code under the header right rear door module and under the header door/gate module code but then later one of those will drop off. I also don't know for sure that everything is scanning correctly. I know there are a certain amount of tests that the engine computers do before history codes will fall off but sometimes it feels like the scan will say completed but it's not really showing me everything and then the next time I will see some of the history codes and they will be gone the next time and new history codes will be shown. It seems to be the same codes right now cycling through being listed under different modules and areas. For example, u1041 will sometimes show up as an airbag code under that airbag header and later it's showing up with the airbag information under the header for body control module. Sometimes they show up together under both at the same time.
Am I looking at something like a ground somewhere or am I looking at all of the various modules and systems all failing at the same time? BCM, door/gate, right rear door module as well as brake traction system, hvac system etc etc? I did read somewhere it could be pins(?) needing to be checked on the serial data bus connector inside the dash on drivers side (I apologize if that's not what it's really called but hopefully someone will know what I mean).
I've seen YouTube videos where they say it's a bad bcm. I've seen forums state it's actually the ecm. Everything I find involves a bunch of reading without the ability to ask questions so I've come here. I can warn you in advance that I will likely have many.
Elizabeth