JLG 450A II Series, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
3121290 – JLG Lift – 3-165
DTC 1652- TPS1 Loss of Communications
• Throttle Actuator (with serial/digital position feedback).
• Check Condition- Key On, Engine Running and/or Stopped.
• Fault Condition- ECM is expecting to receive throttle posi-
tion information from the throttle actuator and is not.
• Corrective Action(s)- Illuminate MIL, sound audible warn-
ing or illuminate secondary warning lamp. Shutdown
engine.
• Non-emissions related fault.
For a throttle actuator with serial/digital position feedback,
the ECM receives a constant data stream from the throttle
actuator. If communication is absent or interrupted, the ECM
can no longer control the throttle position.
This fault will set if the key is on, the throttle actuator is receiv-
ing power, and the ECM is not receiving digital information
from the actuator.
Diagnostic Aids
• Verify throttle actuator 5V supply voltage is present at the
actuator.
• Check for a all four TPS feedback wires for short circuits.
• Check TPS SER+ and TPS SER- wire routing with respect to
noise sources (ignition coils, spark plug coil wires, etc.) and
shield if necessary.
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