Rodeo S 2WD L4-2.2L (1999)
Engine Control Module: Description and Operation
PCM Voltage Description
The PCM supplies a buffered voltage to various switches and sensors. It can do this because resistors in the PCM which are so high in value that a test
light may not illuminate when connected to the circuit. An ordinary shop voltmeter may not give an accurate reading because the voltmeter input
impedance is too low. Use a 10-megohm input impedance digital voltmeter (such as J 39200) to assure accurate voltage readings.
The input/output devices in the PCM include analog-to-digital converters, signal buffers, counters, and special drivers. The PCM controls most
components with electronic switches which complete a ground circuit when turned ON. These switches are arranged in groups of 4 and 7, called either a
quad driver module (QDM), which can independently control up to 4 output terminals, or Output Driver Module (ODM) which can independently
control up to 7 outputs. Not all outputs are always used.
