Communication Issues on Your LB7 or LLY?

We have seen a number of communication network issues specifically on the 01-05 trucks. These issues are typically observed as No crank/ No start, IPC (Instrument Panel Cluster) erroneous display- i.e. fuel level display, speed, etc., door locks activating sporadically and automatically, and communications codes between other modules.

This is often caused by corruption or a short in the Class 2 serial data network, and is usually caused by the interface module used with aftermarket radios; meanwhile, one must keep in mind that other aftermarket electronic accessories can also cause similar issues, and that it isn't always that the radio will be the source of these issues. These issues are more commonly seen with radios equipped with GPS.

The diagnosis for this issue can be as easy as removing the radio fuse from the underhood fuse box and observing if the symptoms of the concern persist. Oftentimes these issues begin when batteries get weak and voltages drop below a certain threshold while cranking. Many customers will also experience these symptoms after replacing batteries. We have been oftentimes successful in correcting these issues by removing the radio fuse as previously mentioned, and starting the vehicle, allowing it to run for a few minutes and then while the vehicle is running, reintegrate the radio back into the network by reinstalling the fuse.

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