What is the pcm and ecm. What do they do and were are they located
Thanks

 

PCM/ECM (same thing) is the brains of your vehicle. It's a computer that holds the software which controls the powertrain operation (timing, spark, and fuel primarily). It relies on sensor inputs to make decisions on how your engine should be running. It will also control the transmission shifting for automatic trans, will monitor engine emissions, and perform engine diagnostics. It is what will turn your check engine light on when it detects a problem with the emissions or a problem with the powertrain system operation such as inactive sensors, sensors out of expected ranges, or misfires.

Your vehicle is a computer network composed of different modules that perform specific functions. These modules share and provide data to each other so each can complete their functions. The PCM/ECM (powertrain control module) is just one of them.

Depending on model and year of the vehicle it may be located in different locations. Most times it is located in the engine compartment under the hood. Mine is in the forward area under the hood on the driver's side next to the battery. You can look for one of the fattest cables in the engine compartment coming from the fuse block area and trace it to the module.

Does this help?

 

yes thank you