Passport EX 2WD V6-3.2L SOHC (6VD1) (1997)
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The service programming system (SPS) will not allow incorrect software programming or incorrect calibration changes.
Refer to the latest Tech line information on reprogramming or flashing procedures.
PCM Voltage Description
DESCRIPTION AND OPERATION
The PCM supplies a buffered voltage to various switches and sensors. It can do this because resistance in the PCM is 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 (0DM) which can
independently control up to 7 outputs. Not all outputs are always used.
Use of Circuit Testing Tools
DESCRIPTION AND OPERATION
Do not use a test light to diagnose the powertrain electrical systems unless specifically instructed by the diagnostic procedures. Use Connector Test
Adapter kit J 35616 whenever diagnostic procedures call for probing connectors.
EEPROM
DESCRIPTION AND OPERATION
The Electronically Erasable Programmable Read Only Memory (EEPROM) is a permanent memory that is physically soldered within the
Powertrain Control Module (PCM). The EEPROM contains program and calibration information that the PCM needs to control powertrain
operation.
Unlike the Programmable Read Only Memory (PROM) used in past applications, the EEPROM is not replaceable. If the PCM is replaced, the
new PCM will need to be programmed. Equipment containing the correct program and calibration for the vehicle is required to program the PCM.
