Powertrain control module

There are many hundreds of error codes that can occur, which indicates that some subsection of the car is experiencing a problem.

When one of these errors occurs, usually it will turn on the "check engine" light on the dashboard.

The PCM is one of potentially several on-board computers, or essentially the "brain" of the engine control system.

[1] The primary inputs to the PCM come from many sensors, of different types, that are spread around the car.

Early use of the powertrain control module dates back to the late 1970s[citation needed] - official phasing in[clarification needed] of the PCM occurred during the early 1980s when used in conjunction with electronic controlled carburetors and lockup torque converters (at the time conventional 3-speed automatics received lockup converters at the same time overdrives were introduced[citation needed]).