Your Saab Sonett engine control system detects a problem, the computer stores the diagnostic trouble
code U3977 in its memory.
To figure out what is wrong with your vehicle you must first extract the U3977 DTC For Saab Sonett.
Another consequence of U3977 Saab Sonett engine overheating may be a blown head gasket. Heat makes aluminum swell almost three times faster than cast iron. Thermal stress can distort the head and make it swell in areas that are hottest like those between exhaust valves in adjoining cylinders, and areas that have restricted coolant flow like the narrow area that separates the cylinders. The typical aluminum head swells most in the middle, which can crush the head gasket if the head gets too hot. This will usually cause the head gasket to leak compression between adjacent cylinders, or leak coolant into the cylinders.
U3977 Saab Sonett DTC Meaning
Network Code - Problem is climate control system, lighting, airbags, etc.
SAE - Generic
Exhaust Gas Recirculation System Valve 1
Cruise Control System - Vehicle Accel Too High
There are currently two main types of cylinder deactivation used today, depending on the type of engine. U3977 Saab Sonett code for the pushrod design which uses solenoids to alter the oil pressure delivered to the lifters. In their collapsed state, the lifters are unable to elevate their companion pushrods under the valve rocker arms, resulting in valves that cannot be actuated and remain closed.