Diagnostic Aids

WARNING: This page is about a different car, the 2013 GMC Yukon XL, 2013 GMC Yukon, 2013 Chevrolet Tahoe, 2013 Chevrolet Suburban, and 2013 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0550 detects the wrong copy of non-volatile memory in RAM or a RAM read/write failure.
DTC P0550 detects a non-volatile memory write error.
DTC P0550 detects a corruption of the EPROM/Flash memory.
When attempting to set TCCM internal DTCs, let the engine run for at least 1 minute and then shut the engine OFF for 30 seconds. Following this procedure will allow for a complete TCCM shutdown. Reprogram the TCCM and retest the DTC to see if the DTC resets.
A low voltage condition can sometimes falsely set this DTC. Attempt to clear this DTC and retest.