OBD II will not communicate with computer

Scan tool is C reader Professional

$127 CRP123 V2.0 OBD2 Scanner, 2025 Upgrade 4 Systems Scanner with 3 Reset, Oil, SAS, Throttle Reset, Full OBD2 Code Reader

CRP123. "The CRP is designed for technicians to diagnose Engine, Transmission, ABS and Airbag (SRS) systems. It features an intuitive interface and supports the latest OBDII test modules 1-10. Graph, record, and playback crucial data to more efficiently diagnose driveability issues." I cannot get past the initial readout screen since it simply tells me it cannot communicate.

I have tried using a different scan tool, way early on in this game. I went to O'Reilley's and hooked up theirs. It would not communicate either.

 

Okay, that's a decent, albeit basic tool. Unfortunately, without some additional test equipment such as a lab scope, it will be difficult to do much. My WAG on this is that a module has failed and is pulling the CAN down, prohibiting comms. Is there anything on the truck that doesn't work, or doesn't work properly? Door locks, windows, entertainment/nav?

 

Nope. At present, everything appears to be functioning properly.

 

Weird...

 

Weird indeed, as well as annoying.

 

Hopefully before this becomes totally critical, we plan on getting a new connector and pins, cut off the old one and re-pin it in the assumption that there is a poor connection in there. Anything "science" behind this? Not really. It's just one of those things you do to eliminate possibilities. Next step so to speak.

 

Back again--have yet to try replacing the pigtail which we had all the good intention to do, but it just didn't seem critical.....UNTIL.....popped a CEL 5 hours from home on a road trip and couldn't do any diagnostics. However, after a lot of consideration, it seems that it threw the code and other lights like slip indicator after the truck was gassed up by gas station attendant in Oregon where you are not allowed to pump your own gas. Question of loose cap/leak so reset CEL by disconnecting battery, tightening cap first of course, and doing a little test drive around, so this might just have solved the current problem. Might have since have not hit the road again to get home.

However, it certainly has heightened the need to fix the OBD problem in reading codes as this could have helped a lot. We couldn't check codes at O'Reilley's to diagnose the problem. At this point it's either the connector or the ECM responsible for the disconnect. We intend to splice in a new pigtail which seems to be available as a generic item at a lot of places, then consider a new ECM. Of course will post in results as there are far far too many dead end threads on forums.

 

OBD disconnect issue resolved. Terminal ends in the connector were spread apart and not making connection. Unpinned all the terminals in the connector and "tweaked" them so they were tighter.

https://www.youtube.com/watch?v=8LlyxpCPbNQ

https://artsautomotive.com/home/art-icles/articles-for-the-curious/obd2-connector-repair/

Next issue is now to resolve the codes on the latest problem, maybe considering to get new terminal ends and replace those on the OBD2 port, but the tightening done has resolved the inability to read the codes.