Emissions Recall. General Motors has decided to conduct a Voluntary Emission Recall involving certain vehicles with a 2.7L engine (RPO L3B). The Engine Control Module (ECM) may not properly diagnose, may not set Diagnostic Trouble Codes (DTCs) or may not illuminate the Malfunction Indicator Light (Check Engine Light) if certain fault conditions of the catalytic converter were to occur. Dealers are to reprogram the ECM.