Electric Powertrain Control - Overview: Overview

WARNING: This page is about a different variant/trim than selected.

The center of the electric motor control system is a microprocessor called the PCM. The PCM receives inputs from sensors and other electronic components. Based on information received and programmed into its memory, the PCM generates output signals to control various relays, solenoids, and actuators. This vehicle uses two PCM connectors.

The PCM stores information in keep alive RAM (a memory integrated circuit chip) about vehicle operating conditions, and then uses this information to compensate for component variability. Keep Alive Memory (KAM) remains powered when the ignition is off so this information is not lost.

The Vehicle Battery Power (VBPWR) is a PCM-supplied power source that supplies regulated voltage (5 to 12 volts) to vehicle sensors that run off 12 volts but cannot withstand VPWR voltage variations. It is regulated to VPWR minus 1.5 volts and is voltage limited to protect the sensors. VPWR is the primary source of PCM power. VPWR is switched through the PCM power relay and is controlled by the PCM. The VREF is a positive voltage (about 5 volts) that is output by the PCM. This is a consistent voltage that is used by the three-wire sensors. The Signal Return (SIG RTN) is a dedicated ground circuit used by the sensors and some of the other PCM inputs.