This bulletin applies to 2007-2013 Chevy Avalanche vehicles. The following concerns may be present:

- Door locks cycle while driving

- Intermittent no-start/crank

- Service Stabilitrak DIC message

- Speedometer and tachometer freeze while driving

Along with these issues, there will be a High Speed GM LAN history (DTCs U0140 00 and/or U0073 71 stored in any LAN high speed module). This concern can occur if the High Speed GM LAN data circuits (2500 & 2501) have experienced an intermittent short to ground or short to each other two times within a period of less than one second and then goes back to normal. If the scan tool or data bus diagnostic tool is connected to the vehicle, the BCM may appear to be off-line (no communication with the BCM) during that complete ignition cycle, but there will be communication with all other High Speed GM LAN modules.

If this happens, the BCM will not communicate with the other High Speed GM LAN modules or the scan tool until the ignition is turned off and the BCM has completely powered down. This may take up to 20 minutes. Typically, the complaint will be intermittent and will usually occur when driving over bumpy/rough roads. Refer to Testing for Electrical Intermittent's in the service manual to reset the DTC and diagnose the fault location. Do not replace the BCM until normal diagnostics are performed.