19
20 - Wheel System, Traction
1-3
Speed Limit Pot Fault
Description
Speed limit pot fault
Setting
Conditions
Speed limit input voltage out of range for the condition
When Monitored
Always
Possible Causes
•
Speed limit input wire open or shorted
•
Speed limit pot defective
Initial Action
Key-cycle the machine
Troubleshooting Steps
1.
If any throttle errors are reported, diagnose those first.
2. Turn the speed limit potentiometer to its middle position.
3. Power the machine and check the voltage between contacts 3 and 18 of the X30 connector at the
drive controller.
−
If the voltage is between 0.4 and 4.6 volts, and the error persists, replace the drive controller.
−
If the voltage is at or near 0V or at or near 5V, see step 4 to inspect the potentiometer.
4. Check the potentiometer.
a. Disconnect the X105 connector of the control handle (operator’s controls).
b. Check the resistance between contacts 1 and 2, 1 and 4, and 2 and 4 (respectively) of the X105
connector of the control handle.
– If any measurement is open circuit (greater than 100K ohms), repair or replace the speed limit
potentiometer and/or wiring.
– If any measurement to contact 4 results in a reading of at or near 0 ohms, replace the
potentiometer.
– If all 3 measurements are not at or near 0 ohms, the potentiometer is not at fault. Continue to step
5.
5. Check the harness between the drive controller and the control handle.
a. Reconnect the X105 connector at the control handle.
b. Disconnect the X30 connector at the drive controller.
c. Check the resistance between contacts 3 and 18, 13 and 18, and 3 and 13 (respectively) of the X30
connector of the at the drive controller.
– If any measurement is open circuit (greater than 100K ohms), repair or replace the harness
between the drive controller and control handle.
– If any measurement results in a reading of at or near 0 ohms, the harness is shorted. Repair or
replace the harness.
