POWER TRAIN
RT765E-2 SERVICE MANUAL
7-4
Published 9-04-2014, Control # 422-08
ELECTRONIC CONTROL SYSTEM
Description
The engine control system is an electronically operated fuel
control system that also provides many operator and vehicle
features as well as reducing exhaust emissions while
optimizing engine performance.
The ECM performs diagnostic tests on most of its circuits
and will activate a fault code if a problem is detected in one of
these circuits. Along with the fault code identifying the
problem, a snapshot of engine operating parameters at the
time of fault activation is also stored in memory. Some fault
codes will cause a diagnostic lamp to activate to signal the
driver. The fault codes can be read on the steering column
display while the ignition switch is in the RUN position and
the engine is Off. The ECM communicates with service tools
supplied by Cummins through a SAE J1939 datalink.
The ECM also monitors the condition of the diesel particulate
filter and will alert the operator by way of an indicator in the
cab if the filter becomes clogged with carbon. When the filter
becomes clogged, the ECM will control the regeneration
process to clean the filter of particulate matter.
Engine Control System Switches And
Indicator Lights
Engine Diagnostic/Speed Control Switch
The Engine Diagnostic/Speed Control Switch is a two
position maintained on/off rocker switch used to access the
engine fault codes or enable the control of the low engine
idle and engine rpm functions.
Diagnostic function — With the Ignition Switch in the RUN
position and the engine off, press the top of the Engine
Diagnostic/Speed Control Switch to view the engine fault
codes on the steering column display. If there is more than
one active engine fault code, use the Increment/Decrement
Switch to toggle forward and backward through the fault
codes. If there are no engine fault codes, zeroes will be
shown in the steering column display.
Engine low idle function — With the engine running and the
top of the Engine Diagnostic/Speed Control Switch pressed,
the engine low idle is adjusted using the Increment/
Decrement Switch.
Engine rpm function — With the engine running and the
bottom of the Engine Diagnostic/Speed Control Switch
pressed, the engine rpm is adjusted using the Increment/
Decrement Switch.
Increment/Decrement Switch
The Increment/Decrement Switch is a three position
momentary rocker switch with center maintained position
being off. Use this switch to toggle backward and forward
through active engine fault codes or adjust engine speed.
Diagnostic function — With the Ignition Switch in the RUN
position, the engine off, and the top of the Engine Diagnostic/
Speed Control Switch pressed, press the top or bottom of the
Increment/Decrement Switch to toggle forward and
backward through the engine fault codes shown on the
steering column display. If there are no engine fault codes,
zeroes will be shown in the steering column display.
Engine low idle function — With the engine running and the
top of the Engine Diagnostic/Speed Control Switch pressed,
press the top or bottom of the Increment/Decrement Switch
to increase or decrease the low engine idle.
Engine rpm function — With the engine running and the
bottom of the Engine Diagnostic/Speed Control Switch
pressed, the Increment/Decrement Switch is used to adjust
engine rpm. Quickly press the top of the switch once to go to
full engine rpm; quickly press the bottom of the switch once
to return to low engine idle. If the engine speed is below the
maximum rpm setting, pressing and holding the top of the
switch will cause the engine rpm to slowly increase; release
the switch when the desired rpm is attained. If the engine
speed is above the minimum rpm setting, pressing and
holding the bottom of the switch will cause the engine rpm to
slowly decrease; release the switch when the desired rpm is
attained.
Engine Stop Light
The Engine Stop Light is located in the steering column
gauge display. It is a red indicator light that illuminates to
signify a serious engine problem that requires the vehicle
and the engine to be stopped as soon as safely possible.
The engine should remain shut down until the fault can be
repaired.
Engine Warning Light
The Engine Warning Light is located in the steering column
gauge display. It is an amber indicator light that is a part of
the engine’s electronic control system and when illuminated,
gives the operator a signal that there is a engine problem
which must be corrected.
Diesel Particulate Filter Indicator (Tier 4 Engines
Only)
The Diesel Particulate Filter (DPF) indicator is located in the
steering column gauge display. This indicator illuminates
Reference Only
