Oshkosh JLG 400S, Service And Maintenance Manual

Page: 260 / 462

SECTION 3 - CHASSIS & TURNTABLE
3-208 – JLG Lift – 3120895
DTC 2112- Unable to Reach Higher TPS
• Throttle Position Sensor
• Check Condition-Cranking or Running
• Fault Condition-Throttle command is 20% more than
actual throttle position
• MIL-On during active fault
• Engine Shut Down
In the case of a diesel engine, an actuator controls a fuel
injection pump, directly affecting the fueling level into the
cylinders. This may be by direct manipulation of the fuel
injection pump rack or by manipulation of the mechanical
governor control level or "throttle arm." In the DGC ECM
and EDIS, references to the throttle and throttle position
sensor refer to these fuel injection pump control actuators
and their position feedback sensors. When the fuel injec-
tion pump is electronically controlled it can be used to
control the idle stability and limit engine speed based on
operating conditions.
The Throttle Position Sensor uses either 1) a variable
resistor and voltage divider circuit or 2) a non-contact hall-
effect sensor to determine throttle actuator position, and is
located within the throttle actuator.
There are two types of throttle actuators, 1) actuator with
analog position feedback and 2) actuator with digital posi-
tion feedback. The first type, with analog position feed-
back, provides an analog return signal between 0 and 5
volts that is proportional to the throttle actuator position.
The second type, with digital position feedback, provides
a serial data signal to the ECM with the throttle actuator
position voltage level encoded in the data stream.
This fault will set if the throttle command is 20% or more
than the actual throttle position. During this active fault the
MIL light will be on and the engine will shut down.
Electronic Throttle
Actuator w/Serial
Position Feedback
2
16
13
12
1
5V_ext
Vs=+5 VDC
5V_rtn
TPS1
TPS SER +
+
-
Motor
DBW-
DBW+
ECM
H-Bridge
19
TPS SER -
Serial
xmitter