For some years now, I have not been to connect to the PCM on the truck - as far as writing or reading a tune.

Using my Autotap interface - can't connect
Using the LS1Edit interface - can't connect
Service Dept. Tech II - can't connect

Actron 9145 scanner - CAN connect. I can reset codes, look at live data, etc. No issues with the Actron.

The ALDL has four wires:
12+ : is good, power is there
ground: works
ground: works
serial bus: obviously works as I receive data to the Actron scanner.

Any input as to why these other devices cannot communicate?
Any advice on what else to troubleshoot?

Thanks.

 

check the cig liter fuse

 

I knew I forgot to list something, thanks for the reminder.

I also couldn't find a blown fuse anywhere. I checked every fuse in the truck.

 

Problem resolved.

I took a good look at the terminals. The serial bus terminal and one of the ground terminals looked flat. I removed them from the connector, pushed the tabs back up, and reinserted back into the connector.

Everything now works. Good connections on every terminal.