Code 52, ECM Fault
WARNING: This page does not describe the selected car, but rather 22 other vehicles, including the 1992 GMC Yukon, 1992 GMC Vandura Special, 1992 GMC Vandura, 1992 GMC Value Van, and 1992 GMC Rally Camper Special. However, it is still accessible from the selected car via links, so may be relevant.
Ensure ECM connectors are fully inserted. Clear ECM memory. Start engine and check for SERVICE ENGINE SOON light. If light and Code 52 reappear, replace ECM. After repairs, clear ECM memory to confirm no SERVICE ENGINE SOON light.