05GMC4.8

p2544, u0100, u0073

2008 gmt900 1500 sierra 4x2 5.3/4l80e. gauges were going crazy and doors unlocking/locking, service traction control/abs. no codes poped up but these were in the pending list.

also the other day i had a code pop up for an ignition switch and on for the CEL requested from the fscm.

im so sick of these electric issues on these trucks but its paid off and i dont need another payment.

any help is greatly appreciated

DrX

iTrader: (7)

Codes seem most likely due to loss of communication between the ECM and TCM.

I believe the GMLAN lines pass through the TCM on their way to the ECM. So removal of the TCM would cut communication between the ECM and other modules on the high speed LAN. If it has been removed, you would have to dig the 2 twisted pairs out of the engine harness, or at the TCM connector, and splice them together. I am guessing they are TN and TN/BK twisted together if the same as the swap I am working on. If you are still using the factory TCM, but reprogrammed it for a 80E, then check that there are no breaks in those wires, check the terminals in the TCM connectors, and check that the connector is properly secured to the TCM.

Some useful info here: GMLAN

As per the article, you should read 60 ohms between pins 6 and 14 on the DLC with the battery disconnected. If it is double that, the ECM is disconnected from the LAN.

Gmmastertech1

Known problem. Google this bulletin number: 08-07-30-021H It should help you out.

05GMC4.8

thanks a bunch for that link, that may explain the intermittent transmission issues i have been having. i used the pcm of nc swap harness that allows me to use the 60e tune