Grove
Published 01-14-2021 Control # 707-01
7-5
TMS9000-2 SERVICE MANUAL
POWER TRAIN
7
ENGINE CONTROL SYSTEM
Description
The engine control system is an electronically controlled fuel
injection system that optimizes fuel economy and reduces
exhaust emissions. It accomplishes this by controlling the
torque and horsepower curve, air fuel control function,
engine high speed, low idle and road speed. The system
monitors critical engine temperatures and pressures, and will
log diagnostic faults when an abnormal operating condition
occurs. If an out of range condition exists, and engine derate
action is to be initiated, the operator will be alerted by an in-
cab warning light. The warning light will blink or flash when
out-of-range conditions continue to get worse.
Functional Operation
Four key switch phases govern the operation of the engine
control system:
1.
Ignition switch in the on position, idle/diagnostic switch
off, engine not cranking or running.
2.
Ignition switch in the on position, idle/diagnostic switch
on, engine not cranking or running.
3.
Ignition switch in the on position, engine cranking.
4.
Ignition switch in the on position, engine running.
With the ignition switch on, the diagnostic test switch off and
the engine not cranking or running, the electronic control
module (ECM) performs diagnostic and status operations. It
reads the logic inputs from the brake, clutch, and cab
switches and analog inputs from sensors such as the engine
coolant temperature sensor and the manifold boost pressure
sensor. During this phase the data link is active and can be
accessed by the applicable service tools. The ECM opens
the fuel shutoff valve so the engine is ready to be started.
Additionally if the key switch is turned on but the diagnostic
switch remains off, the indicator lights illuminate for
approximately two seconds to verify they are working and
then go out. This is part of the normal operation of the power-
up sequence. However, if an active fault is present, one of
the lights remains illuminated, determined by the type of fault
being sensed.
When the diagnostic test switch is turned on, the red and
amber indicator lights illuminate and remain illuminated if
there is no active fault. If there is an active fault, the red lamp
flashes in a sequence of pulses to indicate that specific fault
code.
The electronic subsystem and the starter motor are
independent of each other. During the cranking phase, with
the ignition switch in the start position, the ECM commands
all of the fuel needed to start the engine. There is no need to
use the throttle pedal while cranking the engine.
While the engine is cranking the ECM is performing
additional diagnostic and status operations. An active fault
causes one of the two indicator lamps to illuminate and
remain lit. Which lamp is illuminated depends on the severity
of the fault.
OK
OK
OK
Missing Material
Traverse Cracks
Longitudinal Cracks Intersecting
with Transverse Cracks must be
Replaced
V-Ribbed Belt Inspection
FIGURE 7-2
Fo
r
Reference
Only
