JLG Telehandler 33255 Fault Code: UGM Output Drivers - Transmission E Coil - Open Circuit
UGM Output Drivers - Transmission E Coil - Open Circuit · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Fault code 33255 sets when the UGM (universal ground module/main controller) detects an open circuit on the transmission E control coil output (J1-7) on a powershift-configured telehandler. The controller deactivates that gear coil, limits gear selection to 3rd and 4th only, and flashes the gear selection symbol on the cabin display. The fault latches until the machine is power cycled.
Medium severity. The machine keeps running and can still be driven, but gear selection is limited to 3rd and 4th only, which affects low-speed control, maneuvering, and load handling in tight areas. Treat it as a diagnose-this-shift issue rather than an emergency shutdown, but do not ignore it since reduced gear availability can be unsafe in certain work conditions.
What does JLG Telehandler error code 33255 mean?
Fault code 33255 is set by the UGM (the machine's main output control module) when it detects an open circuit on the output that drives the transmission E control coil, wired through connector position J1-7. This coil is one of the gear selection solenoids in a powershift transmission setup.
When the UGM sees this open circuit, it shuts off that specific coil output entirely so it cannot be commanded on. Since that coil is tied to certain gear selections, the machine's available gearing is reduced to 3rd and 4th only. The operator will see the gear selection symbol flashing on the cabin display as a visual alert that something is wrong with gear selection.
This is a machine system distress indicator, meaning it is flagged as a notable operational fault but not necessarily a machine shutdown condition. The transmission still functions, just with restricted gear range.
What triggers a JLG Telehandler 33255 code?
The UGM sets this fault when the machine's transmission is configured as powershift and the controller detects an open circuit condition at the transmission E control coil output, wired at J1-7.
Common causes of 33255
- Open circuit in the wiring harness between the UGM output and the transmission E control coil, including chafed, cut, or corroded wiring
- Failed or disconnected connector at J1-7
- Faulty or burned out transmission E control coil (solenoid) with no continuity
- Poor or corroded ground or pin connection at the coil connector
- Internal UGM output driver failure (less common, but possible if wiring and coil both check out good)
How to troubleshoot JLG Telehandler 33255: first checks
- Inspect the wiring harness from the UGM to the transmission E control coil for visible damage, chafing, or disconnection, paying close attention to the J1-7 connector pin
- Check the connector at J1-7 for corrosion, bent pins, or a loose connection and reseat or clean as needed
- Measure continuity across the transmission E control coil itself to confirm the coil winding is not open
- Check for continuity across the full length of wiring from the UGM output to the coil to isolate whether the break is in the harness or at the coil
- Confirm the transmission is actually configured as powershift, since this fault only applies in that configuration
- Verify machine ground connections near the transmission are clean and tight
How the code clears
This fault latches until the machine is power cycled. After repairing the open circuit, whether it is a wiring repair, connector cleaning, or coil replacement, cycle the machine's power off and back on to attempt to clear the fault. No separate reset procedure is listed for this code beyond the power cycle.
Frequently asked questions
What does JLG fault code 33255 mean?
It means the UGM has detected an open circuit on the output that controls the transmission E control coil (wired at J1-7) on a powershift-configured machine. The controller disables that coil and limits gear selection to 3rd and 4th only.
Can I keep operating the telehandler with fault code 33255 active?
The machine will still drive, but only in 3rd and 4th gear until the fault is fixed and cleared. Depending on your work conditions, that limited gear range may not give you the low-speed control you need, so it is best to diagnose and repair the open circuit as soon as practical.
Why is my gear selection symbol flashing on the display?
The flashing gear selection symbol is the cabin display's way of alerting the operator that a gear-related fault is active, in this case an open circuit on the transmission E control coil output.
How do I clear fault code 33255 after repair?
This fault latches until the machine is power cycled. Once you have repaired the open circuit, whether in the wiring, connector, or coil, turn the machine off and back on to clear the latch.
What parts should I check first for this fault?
Start with the wiring harness and connector at J1-7, check the transmission E control coil for continuity, and confirm ground connections are clean. Most open circuit faults trace back to a damaged wire, a bad connector, or a failed coil.
Does this fault only apply to certain transmission setups?
Yes. This fault is only triggered when the transmission is configured as powershift. If your machine uses a different transmission configuration, this specific fault would not apply.
Will this fault damage the transmission if left unrepaired?
There is no indication that leaving this fault active causes further transmission damage. The main operational impact listed is the loss of gear selection outside of 3rd and 4th gear.