Dtc 123- tps1 signal voltage high, Dtc 123- tps1 signal voltage high -169 – JLG 450A_AJ Series II Service Manual User Manual
Page 219
SECTION 3 - CHASSIS & TURNTABLE
3121180
– JLG Lift –
3-169
DTC 123- TPS1 Signal Voltage High
• Throttle Position Sensor 1.
• Check Condition-Key On, Engine Off.
• Fault Condition-TPS1 sensor voltage higher than the
limit defined in the diagnostic calibration.
• Corrective Action(s): Sound audible warning or illumi-
nate secondary warning lamp, shutdown engine.
• Non-emissions related fault.
In the case of a diesel engine, an actuator controls a fuel
injection pump, directly affecting fueling level into the cyl-
inders. 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 throttle and throttle position sen-
sor 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 TPS1 voltage is higher than the limit set
in the diagnostic calibration at any operating condition
while the engine is cranking or running. The limit is gener-
ally set to 4.90 VDC. In many cases, this condition is
caused by a short-to-power of the TPS circuit in the wire
harness or a failure of the sensor. This fault should be con-
figured to trigger an engine shutdown and the engine will
not start with this fault active.
E
le
c
tro
n
ic
T
h
ro
ttle
A
c
tu
a
to
r w
/Se
ria
l
P
o
s
itio
n
F
e
e
db
a
c
k
2
1
6
1
3
1
2
1
5
V
_e
x
t
V
s
=
+
5
V
DC
5
V
_
rtn
T
P
S
1
T
P
S
S
ER
+
+
-M
o
to
r
D
B
W-
D
B
W+
E
C
M
H
-B
rid
g
e
1
9
T
P
S
S
ER
-
S
e
ria
l
x
m
itte
r
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