Bravada 2WD L6-4.2L VIN S (2002)
Engine Control Module: Description and Operation
POWERTRAIN CONTROL MODULE - 1
The Powertrain Control Module (PCM) contains the remainder of the logic of the theft deterrent system. If a class 2 message containing a valid
password is received from the BCM, the PCM will continue to allow the fuel injectors to operate. The PCM will allow the fuel injectors to operate
until it decides there is no valid password coming from the BCM. If the PCM does not receive a class 2 message, or receives a class 2 message with an
incorrect password, the engine will crank and will not run or will start and stall immediately.
POWERTRAIN CONTROL MODULE (PCM) - 2
The PCM verifies that the password received from the theft deterrent control module via the serial data circuit is correct. The PCM can learn only one
fuel continue password. If the fuel continue password is correct, the PCM enables the starting and fuel delivery systems.
The PCM disables the starting and fuel delivery systems if any of the following conditions occur:
^
The fuel continue password is incorrect.
^
The fuel disable password is sent by the theft deterrent control module.
^
No passwords are received - there is no communication with the theft deterrent control module.
The PCM controls all ignition system functions, and constantly corrects the spark timing. The PCM monitors information from various sensor inputs that
include the following:
^
The throttle position (TP) sensor
^
The engine coolant temperature (ECT) sensor
^
The mass air flow (MAF) sensor
^
The intake air temperature (IAT) sensor
^
The vehicle speed sensor (VSS)
^
The transmission gear position or range information sensors
^
The engine knock sensors (KS)
