Lull 944E-42 Service Manual - Manual (Page 66)

Cab and Covers
4-6 944E-42
4.3.5 Throttle Position Sensor Replacement
a. Throttle Position Sensor Removal
The throttle position sensor controls the engine speed. It
is designed to sense the position of the throttle pedal and
send the signal back to the engine control module.
The sensor is located on the bracket below the dash
where the throttle pedal is attached.
The sensor must be tested while it is still on the machine.
Refer to step “C”.
1. Park the machine on a firm, level surface, level the
machine, fully retract the boom, lower the boom,
place the travel select lever in the (N) NEUTRAL
position, engage the parking brake and turn the
engine OFF.
2. Disconnect the ECM cab harness connector (1) from
the throttle position sensor (2).
3. Disconnect the bottom of the return spring (3) from
the bolt at the bottom of the mounting bracket inside
the cab.
4. Remove the clevis locking pin (4) from the clevis on
the linkage assembly.
5. Remove the two slotted pan head screws securing
the sensor and linkage assembly to the mounting
bracket.
6. Slide the sensor (2) and linkage assembly out of the
slot on the mounting plate.
7. Remove the snap ring (5) and flat washer securing
the sensor to the linkage assembly (6).
b. Throttle Position Sensor Installation
1. Slide the sensor onto the linkage assembly shaft.
2. Lock in place on the shaft using the flat washer and
snap ring.
3. Slide the sensor and linkage assembly into the slot
on the mounting plate.
4. Line up the hole in the clevis on the linkage
assembly with the hole on the throttle pedal stop
plate.
5. Secure the clevis with the clevis locking pin.
6. Center and secure the sensor to the cab mounting
bracket with two slotted pan head screws, washers
and nuts. Torque nuts to 2-4 lb-ft (1,5-3 Nm).
7. Connect the ECM cab harness connector to the
throttle rotary sensor.
8. Start the engine. Engine rpm should increase as
soon as the throttle pedal is depressed and continue
to increase until the throttle pedal is fully depressed.
c. Throttle Position Sensor Adjustment
1. Inspect the sensor terminals for continuity. Attach
the ohmmeter leads to the two outside pins, 1 and 3.
The resistance reading should be approximately
4,000 - 6,000 ohms, whether the pedal is at rest or at
fully depressed.
Attach the ohmmeter leads to pins 2 and 3. The
resistance reading should be approximately 2,000
ohms, with the throttle at rest and change to
approximately 4,000 ohms, with the throttle pedal
fully depressed.
2. Replace the sensor if the readings are not as
described in step 1.
MU5741
2
1
4
3
MU5761
6
5