What You Should Know About Powertrain Control Modules

As any car lover or mechanic knows, a vehicle is comprised of many different parts, each of which has a different function. So, how do all the various parts inside a car operate so smoothly together? You have the car’s powertrain control module to thank for that.
As the onboard control unit for a vehicle’s transmission, charging, emissions and other modules, the PCM is essential for keeping a car running smoothly. The PCM not only notifies the driver when problems with the vehicle occur, but it is also one of the key components for maintaining the vehicle’s overall well-being. Here’s what you need to know about powertrain control modules before embarking on your career as a mechanic.

The PCM is Essentially the Brains Behind the Car’s Everyday Operations

In many ways, a powertrain control module coordinates and controls a car’s various functions, much like how the brain does the same for human beings. The PCM takes information from sensors located throughout the car and uses this data to help improve the performance and management of the engine.
Additionally, should problems arise in the car’s transmission or any other subsystem, it is the PCM that will typically alert the driver so they can rectify the issue. Should the powertrain control module not function correctly, subsystems within the vehicle will not be able to communicate normally with one another, leading to possible damage to the vehicle. Among the components that are controlled by the PCM include the automatic transmission, anti-lock brakes and fuel injection systems, among others.

Two Control Units Comprise the PCM: the Engine’s and the Transmission’s

The powertrain control module has two subsystems working together to essentially act as the vehicle’s computer: the engine control units (ECU) and the transmission control units (TCU). With the former, a number of actuators within the vehicle’s internal combustion engine are controlled to maximize the performance of the engine, such as by controlling functions like fuel injection and ignition timing. The TCU, meanwhile, changes gears based on information from sensors in order to help improve the vehicle’s fuel economy and the performance of its engine. Any student hoping to graduate from auto mechanic college will need to know how both components function, and how to diagnose and resolve any problems with either one.

The engine control unit is one of the PCU’s two subsystems

To Become a Mechanic, Learn How to Resolve Issues with the PCM

There are various ways a powertrain control module can malfunction or become damaged, and it’s important to study the processes for how to repair and/or replace it. Whether it’s through corrosion (by water or any other substance), short circuiting, or general wear and tear, it’s important for anyone hoping to become a mechanic to know how to resolve these problems so that the PCM can function properly again.
Check the subsystems of the engine to ensure all components are running smoothly, especially if the car has issues starting or if the engine’s performance is subpar. If this is the case, a partial or full replacement of the PCM is likely necessary—though only a partial replacement is often the case if certain parts are the root of the problem. Either way, you should make sure your customers know that when it comes to diagnosing and repairing problems with the PCM, this is a job best left to the pros.