Bmw M4 U0121 Engine Error Code

When you check Bmw M4 car engine light came on code U0121 the reason should be Engine Light ON (or Service Engine Soon Warning Light). However Bmw manufacturer may have a different definition for the U0121 OBD-II Diagnostic Network (U) Trouble Code. So you should chech it on our car models.

Another consequence of U0121 Bmw M4 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.

Bmw M4 U0121 OBD-II Diagnostic Network (U) Trouble Code Description Bmw M4 car U0121 OBD-II Trouble Code Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and comm Reason For Bmw M4 U0121 Code The reason of Bmw M4 U0121 OBD-II Engine Error Code is U0121 Lost Communication With Electronic Brake Control Module.

While fuel economy was increased, acceleration was seriously compromised, and the loss of engine vacuum led to a dangerous loss of braking assist when the U0121 Bmw M4 code system was in four-cylinder mode. In addition to these issues, while the company proposed a hydraulically controlled system that could be switched from within the car, the version they implemented had to be manually changed in the engine compartment using hand tools.

Bmw M4 U0121 Possible Solution :

In-line Ford engines, along with those of most other manufacturers, begin the numbering of cylinders at the front and proceed in numerical order toward the back. In the V-engine design, Ford follows a similar design with the number one cylinder at the front left of the engine. In the V-6 configuration, cylinder 4 is at the front right of the engine and in a V-8, cylinder number 5 is in that location. Other manufacturers sometimes use an alternating pattern in the V-engines.

What does fault code U0121 mean for Bmw M4 ? What does a diagnostic reading U0121 mean for Bmw M4 ? How to fix OBD2 Code U0121 for Bmw M4 ? What do we know about U0121 code for Bmw M4 ?