Operation

OPERATION

The Powertrain Control Module is a pre-programmed, microprocessor-based digital computer. It regulates ignition timing, air-fuel ratio, emission control devices, charging system, certain transmission features, speed control, air conditioning compressor clutch engagement and idle speed. The Powertrain Control Module can adapt its programming to meet changing operating conditions.

The Powertrain Control Module receives input signals from various switches and sensors. Based on these inputs, the Powertrain Control Module regulates various engine and vehicle operations through different system components. These components are referred to as Powertrain Control Module outputs. The sensors and switches that provide inputs to the Powertrain Control Module are considered Powertrain Control Module inputs.

The Powertrain Control Module adjusts ignition timing based upon inputs it receives from sensors that react to: engine rpm, manifold absolute pressure, engine coolant temperature, throttle position, transmission gear selection (automatic transmission), vehicle speed and the brake switch.

The Powertrain Control Module adjusts idle speed based on inputs it receives from sensors that react to: throttle position, vehicle speed, transmission gear selection, engine coolant temperature and from inputs it receives from the air conditioning clutch switch and brake switch.

Based on inputs that it receives, the Powertrain Control Module adjusts ignition timing. The Powertrain Control Module also adjusts the generator charge rate through control of the generator field and provides speed control operation.