Keep in mind this is my daily and it runs and drives just fine. Idle isn't rough, or any better or worse than my mother's 2016 corolla

 

These codes from Car Gauge Pro make a lot more sense. Chalk one up for Car Gauge Pro over Torque. Now clear them and see what comes back.

http://westersgarage.eidnet.ca/OBD2%...le%20Codes.pdf

P0449 Evaporative Emission Control System Vent Valve/SolenoidCircuit
P1626 Anti-Theft Failure
B3137All door lock circuit low
U1041 Lost communications with Brake/Traction Control System (ABS module)
U1064 Lost communications with Body Multiple Control System (BCM)
U1088 Lost communications (found elsewhere that U1088 is lost communications with Airbag module)

 

Looks like it is losing serial data communications between PCM and multiple modules on the vehicle network. So off the top of my head I wouldn't think that the modules could be the problem unless one was pulling down the entire serial data line. If this was happening, then you might be able to unplug the offender as a test.

Would really have to go to factory manual for diagnostic charts for these codes. Alldata should help with the diagnostics, but may or may not need a Tech 2 to use the factory charts. I suppose inspecting the serial data line starting at the PCM connector would be where I would start if I couldn't accomplish factory diagnosis. Really need to see the wiring charts to see what is where in the wiring. Fact that scanner communication is sometimes nil could be helpful for testing if OBD2 port is first on the serial data line.

 

well I've tried disconnecting the airbag module, bcm, and cluster (but I couldn't see what was going on but still couldn' connect), but I haven' tried any others yet. The connections on the PCM are fine. I tried clearing the codes this morning but it won' connect. If I can find the SP for the data lines I will try just connecting the pcm to the OBD port and see if I can connect to the PCM, but it's cold here in northern Indiana and I don' have a garage. As stated though it only connects when the gear indicator is on and both the temperature and fuel gauge are up, which is not every time unfortunately

 

I'm also northern Indiana. What city are you in? Just curious.

One more day of cold and then we should have nicer weather.

 

https://www.google.ca/search?q=2004+...7i1qZg9iZJXuvM:

Here's all the serial data wiring.

I think your choices are:

If any of the wires leading to SP201 are grounding out, it would definitely pull the entire serial data line down.
If any of the modules hooked to SP201 are internally shorted, it could pull the entire serial data line down
If circuit 1049 is open, then PCM can't communicate with anything.
Or PCM ground is bad.
Or PCM is bad.

Here's the location of SP201 and the pin assignments. You can do a lot with a multimeter checking continuity and shorts to ground here. Can even bypass the rest of the modules by jumpering PCM to the OBD2 connector and see if it will connect.

Maybe its something as simple as the SP201 not plugged in all the way.

Good luck.

https://www.google.ca/search?q=blazer+sp201&tbm=isch&source=iu&ictx=1&fi r=b-fTAWUbYQS5-M%253A%252C35z89e4C8e89hM%252C_&usg=__PKj9EfojVfBr BJutfE9TdlPtf_E%3D&sa=X&ved=0ahUKEwir5drh28HaAhUKi 1QKHTJ2ClkQ9QEILTAC#imgrc=b-fTAWUbYQS5-M:

https://workshop-manuals.com/chevrolet/s10/t10_blazer_2wd/v6-4.3l_vin_x/power_and_ground_distribution/multiple_junction_connector/component_information/diagrams/c100_c119/page_5792/

https://workshop-manuals.com/chevrolet/s10/t10_blazer_2wd/v6-4.3l_vin_x/power_and_ground_distribution/multiple_junction_connector/component_information/diagrams/c100_c119/page_5793/

 

alright so it seems to want to connect after it sits for a while. I cleared all codes with CGP and the re-read them and only got one U1041

 

got anything on alldata on the U codes? I'm still at work. I'll see if I have anything on them at home tonight. You can start looking at SP201. Got a multimeter?

 

I havent been able to work on anything yet, because of working 22 hrs in the last 2 days. finally off today and it looks decent out, but i have to run into work to get access to alldata. ill be poking around for a while and see what i can find. the evap solenoid dtc makes me wonder if it could be shorting our the pcm and bringing the data lines down? Something i will be testing while im out there

 

I found the U-code diagnostic charts under body in the factory manual. Probably the same in alldata. Looks like one of first steps is to use Tech2 to test data line connections with the individual modules and the PCM. Unfortunately we don't have that option.

If Car Gauge Pro won't connect with PCM and has both power and ground at the OBD2 connector, then the data line between the OBD2 connector and the PCM would be suspect as being open or shorted either at the wire or internally inside one of the modules that PCM expects to communicate with. You could unplug modules to eliminate them as a source of dragging down the data line and causing non-communication of scanner with the PCM. You could also remove the splice pack and jumper pins A and B at SP201 connector to accomplish the same thing and see if you get reliable connection with the PCM each time you try.

Since you have been "flowing" solder connections on the Instrument Cluster, you might want to disconnect it and see if it is the thing dragging down the data line communications with other modules and causing connection problems at the OBD2 connector. Just an idea. I'm really into uncharted territory here ......