intermittent fault codes: P2544, P150C, P069E, P0700 (limp mode)

[that modern carpenter]

Hey guys, I'm having a real tough time with my 2013 chevrolet silverado 4.8L V8 the engine is an L20 Vortec. 

I'm getting all these nasty fault codes and they are intermittent and usually start acting up when I'm driving in the city.

       When the engine is warm and I stop in traffic, or hit a crawl speed. The truck normally kicks into "limp mode" and all these fault codes start up ex. P2544 ( regularly) P150C, P069E, and recently P0700. now there is a list of communication codes, but normally its U0073, U0100, and U0109. 

      I've gone to a few auto shops and they kinda said god luck, The dealer had no idea what i was talking about, started with cleaning all my grounds, as well as my fuses, everything seems to be in order. My brother (who is a mechanic) seems to think my TCM is at fault and not working, but I'm hesitant to call that the problem because Im pretty sure its in my transmission which seems like a fairly big job.

Everything else runs fine and there is no problems at all when the truck isn't acting up. Any thoughts or suggestions? I'm pretty desperate to fix this as I plan on taking it to Alaska in july

[sefiroxx]

Be sure to post code descriptions so 100's of us don't have to look then up.

If idle drops too low, misfire, alternator drops, etc can cause all sorts of random codes including communication errors.

Limp mode can be caused by
- errors from the tranny
- failure to communicate with the tranny
- severe out he range measurements from some sensors (ie water temp)

[that modern carpenter]

Never had any misfires, and idle isn’t an issue with the truck. I’m going to try for a new tcm. It’s only 180$ I’ll let you know if that works 

[that modern carpenter]

so the codes that have come back since the TCM has been replaced are:

U0073: ( stands for Control Module Communication Bus 'A' Off. The computers in modern vehicles (referred to as modules) communicate with one another over a data bus. This bus is called the controller area network (CAN). ... When there's a communication problem, the system will store a 'U' diagnostic trouble code (DTC)

 U0109:  defined as a Lost Communication With Fuel Pump Control Module.

so the TCM helped but didn't solve the problem, I think my last resort is to start rooting around for loose connections, does anyone know what i should be looking for particularly? 

 

[Matt2]

On 6/21/2019 at 8:13 PM, that modern carpenter said:

so the codes that have come back since the TCM has been replaced are:

U0073: ( stands for Control Module Communication Bus 'A' Off. The computers in modern vehicles (referred to as modules) communicate with one another over a data bus. This bus is called the controller area network (CAN). ... When there's a communication problem, the system will store a 'U' diagnostic trouble code (DTC)

 U0109:  defined as a Lost Communication With Fuel Pump Control Module.

so the TCM helped but didn't solve the problem, I think my last resort is to start rooting around for loose connections, does anyone know what i should be looking for particularly? 

 

I’m having the exact issue in my Colorado. Did you ever get it fixed?