DTC U1000 & U1255: Class 2 Communication Malfunction: Description

WARNING: This page is about a different car, the 2000 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

Serial data circuit is used to communicate information between systems. Each system on the serial data line is assigned its own identification number, which is used to identify which module or system is communicating. Systems periodically send a State of Health (SOH) message to other systems. If those systems fail to send an SOH message back, a corresponding DTC will be set. Also, any system that cannot communicate properly will set the corresponding DTC.

DTC U1000 or U1255 will set when module or system does not associate an identification number with a SOH message within five seconds.

DTC U1000 or U1255 will change from current to history after current ignition cycle if fault no longer exists. DTC U1000 or U1255 can be cleared using Drivers Information Center (DIC) or scan tool.