Engine Control Module (ECM), Aftertreatment Control Module (ACM)
Troubleshooting
Engine Control Module (ECM) Diagnostic Trouble Codes (DTCs)
The manufacturer scan tool is the preferred tool for performing
diagnostic work. Contact your local dealer for more information
or visit “www.premiumtechtool.com”.
Note: The use of a scan tool is necessary to perform diagnostic
work as well as clearing of any diagnostic trouble codes
(DTCs). DTC(s) can no longer be cleared using the vehicles instrument
cluster digital display and stalk switch control.
System Overview
Multiple electronic control units (ECUs) are used; the engine
control module (ECM), instrument control module (ICM), Vehicle
Electronic Control Unit (VECU), transmission control module
(TCM), the gear selector control module (GSCM) and the
aftertreatment control module (ACM). Together, these modules
operate and communicate data link to control a variety of engine
and vehicle cab functions. The ECM controls a variety of
functions related to operation of the engine. The ECM works in
conjunction with the ACM to control the EATS system and reduce
emissions.. The VECU controls cruise control functions,
accessory relay controls and idle shutdown functions.
In addition to their control functions, the modules have on board
diagnostic (OBD) capabilities. The OBD is designed to detect
faults or abnormal conditions that are not within normal operating
parameters. When the system detects a fault or abnormal
condition, the fault will be logged, the vehicle operator will be
advised that a fault has occurred by illumination a malfunction
indicator lamp (MIL). The module may initiate the engine shutdown
procedure if the system determines that the fault could
damage the engine.
In some situations when a fault is detected, the system will enter
a "derate" mode. The derate mode allows continued vehicle
operation but the system may substitute a sensor or signal value
that may result in reduced performance. In some instances,
the system will continue to function but engine power may be
limited to protect the engine and vehicle. Diagnostic trouble codes
(DTCs) logged in the system memory can later be read, to
aid in diagnosing the problem using a Premium Tech Tool.
The VECU and ECM are dependent on each other to perform
their specific control functions. In addition to switch and sensor
data, the broadcast of data between modules also includes various
calculations and conclusions that each module has developed,
based on the input information it has received.
Engine Control Module (ECM), Aftertreatment Control Module
(ACM), Electrical System Version3
Diagnostic Trouble Code (DTC)
