GM Class 2 Data Line Diagnosis and Repair Information

Details to help repair GM data communication problems

[@Brian-iy7mu]

Thanks so much for this video, found the problem in no time because of it. You're the man!

[@purcelltillmanjr.9794]

Thanks for the info

[@ptours99]

i know this is old but i just watched it and it explains alot of things about what is going on with my s10 cluster is goofy half the guages work

[@JonDoe-007]

Concise and to the point, unlike scanner danner whos all over the place.

[@ricol7964]

Glad it helped.

[@asymptoticsingularity9281]

Excellent video

[@marksharp4487]

Thank you for this video.i learned more on this video then the last 10 videos I've watched combined I also subscribed to your channel 👍

[@ricol7964]

Thank you! Glad to help

[@reymarin3865]

​@@ricol7964Sorry to bother you, thanks to your help I narrowed it to the bcm pin out read is high/fluctuating. Any tips from here?

[@awesomefish100]

What is a normal voltage range for the modules on splice pack 203?

[@sish_khan5198]

Wow super

[@kam5661]

Having a major inconsistent issue in my 03’ silverado I can’t figure out. Is there a way I could contact you for input? Not very familiar with GM class 2 & need some help!

[@Prisonmike89]

Is this splice pack 203? I’ve been looking at wiring diagrams and it never tells you where any of these packs are located. That’s for the video this could be what’s wrong with my tahoe. I'm guessing that connector plugs straight into the BCM under the dash? I'm trying to troubleshoot a similar problem on my ride. No rear locks, headlights not working etc.

[@NoBody-fs3hu]

I have a 2004 chevy 2500hd 6.0L it starts then dies in like 2 seconds I have no communication, but there’s power at my OBD2 port. I have no highbeams my windows and locks don’t work. I check all grounds and cleaned them. Any idea what to do now

[@kingblack22ss]

When you find out please let me know

[@JuanRodriguez-dg4jg]

Awesome video. I have comm with everything except pcm power ground good any toughts

[@ricol7964]

Sorry for the very late reply. Was this a collision vehicle? so many questions? is this a replacement PCM that has not been programmed? What scan tool are you using?

[@larryh1956]

Rat chewed coil wire causing it to short to ground on 05 chevy astro 6 cyl. Now I have a problem which I believe is a PCM problem. With such high positive voltage arching to ground my scan tool only shows 4 cyls. I replaced parts. But when I go to data stream tool only shows 4 cyls when it used to show all 6. I can not find info on how to test the pins for the PCM. Also didn't see any damage to the wiring harness. So best guess is the PCM was damaged due to the high voltage arching to ground.

[@dl7150]

Ty!

[@ricol7964]

Glad it helped

[@JohnWilliams-fp3vb]

I'm having a similar problem with a 2005 Chevy malibu only mine will not turn over at all turn the key and kills everything I tried following the wiring and nothing there is a green wire that come from the security sensor (top of ignition) that has been cut Help Please!!!!

[@ricol7964]

Hello, there are so many things that can be happing here and so many questions to even point you in a certain direction. If you have a cut wire or broken wire that has to be addressed first! Have all the codes pulled from every module and see if there is communication codes. That will point you in a certain direction. Figuring out this stuff may not be strait forward.

[@samuelbird612]

So will you have to replace the abs module?

[@ricol7964]

The customer decided he would unplug it and call it good. But yes it should be replaced.

[@lifestylecustoms9354]

Amazing video! You have explained the serial data line and it’s operation very well. The problem that I’m having is that I’ve done an interior swap from a 05 which runs a class 2 serial data line to a 09’ interior including window switches/modules in which run a GM low lan line, said to be consistent with a normal class 2 line. Module has both power and ground but unfunctional. Is there something that can done to make the 09’ module work on the 05’ serial data line? Need help figuring this out please!

[@ricol7964]

Sorry for this late reply. All I can say is Oh Boy you have your work cut out for you. See if you can find a friend that owns or knows a shop were you can try reprogramming it using a factory or pass thru interface. I mention a friend because a dealer prob wont touch it or charge you tons of cash! Look at my video on reprogramming if you need more info on why you need that step. Please let me know what happens and for everyone out there I am trying to keep up with life and apologize for the delays. THANK YOU for the comments

[@pauls9050]

Would a cut abs hub wire cause this. Abs light is on and has been on for a while. 2001 duramax cranks but no start

[@ricol7964]

No a ABS wire issue would not cause a no start. What is the ABS code that you are referring too? I can help you from there. can your scan tool communicate with the ABS module? If not unplug it and see if your vehicle starts. I have seen many times when a defective module takes the data line down. let me know what you find.

[@pauls9050]

@@ricol7964 no codes just an abs light on

[@greghampton4318]

I'm working on a 2002 Tahoe and someone cut wires near the splicepack. I have no communication to any module. The purple wire from the dlc is hanging. Has a parasitic draw also. Will having all these cut wires cause my draw?

[@toxictube392n7]

If you have a minute I sure would appreciate it. I have a 2003 hummer H2, message screen on the dash comes up “Unknown driver “have the electric or not working. I probably worked backwards, but I replace the ECM, BCM and there’s also when you hook the scan to comes on but no communication. Would another place to check be that SP205 port where everything comes together? Any suggestions? I would appreciate it. I’ve worked on this thing so long, and just agitated. Thank you, Richard.

[@pauls9050]

@@toxictube392n7 check the TCM pass through connector seal

[@detailedautodiagnostics]

👍

[@charlieendslow9635]

Thanks so much customer drop off a truck for no start only for 2 sec and then nothing so just pulled chip and not getting any voltage but .1 to .4 out of every prong

[@latunguley]

This one of the only codes that I can see in my Snap On Solus ultra scanner. And my guages are the same, and I have had issues with my windows and doors! Cranks no start, just like the guy below with 2002 LB7 my 2002 LB7 is doing this and no one can tell me why! Same exact issues! no com to tcm or ecm. I am going to roll my key back to access position and try comunication that way, then try unplugging the abs!

[@ricol7964]

What happened?

[@russelswan8027]

I can only start gmc van and sercurity light flash and function correctly

[@gomer715]

you may able to help this a long time coming. Short story if I use my windows at the same time it will put the truck into Reduced Engine Power. All ground have been cleaned and replaced. What else could this be? It gives me a U1000 code with it but my reader won’t dig deeper.

[@ricol7964]

Very Interesting! can this be duplicated every time you use the master switch? Will it do it with any other door switch?

[@gomer715]

@@ricol7964 only when I use both windows going up never down. It drops my voltage quite a bit from probably 14v to 11v then kills the truck. If I have the blower on that’s enough draw to put it in (REP). Even the rear defroster. It’s gotta be wiring would you know where it all ties together? Maybe somewhere to start looking? I don’t think an old battery would do it