Code B334: Loss Of ECM Data: Notes
WARNING: This page is about a different car, the 1990 Buick Riviera and 1990 Buick Reatta. However, it is still accessible from the selected car via links, so may be relevant.
Code B334 will set if communication between ECM and BCM is lost. If the BCM remains powered and only serial communication is lost, the vehicle will still run, however with ignition key on (engine not running), an ELECTRICAL PROBLEM message will illuminate.
NOTE:
Test numbers refer to numbers on diagnostic chart.
Test Number 1) If the ECM looses power or ground, code will set since ECM cannot communicate. It is important to note that engine will not start.
Test Number 2) Since prior checks eliminated an open circuit, fault is poor terminal contact at ECM terminal No. 2A8, a faulty CALPAK connection or a faulty ECM.