JLG Telehandler 33240 Fault Code: UGM Output Drivers - Transmission C Coil - Open Circuit
UGM Output Drivers - Transmission C Coil - Open Circuit · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Code 33240 sets when the UGM detects an open circuit on the transmission C control coil output at J1-10 while the machine is configured for powershift transmission with a 4F/3R gear selection. The controller disables that output, drops gear 4 (the top forward/reverse selection) from availability, leaving only 1st, 2nd, and 3rd gears selectable, and flashes the gear selection symbol on the cabin display.
Medium severity. The machine keeps running and can still be driven in the lower gears, so this is not an immediate shutdown fault. But losing top gear is a real functional limitation and points to a wiring or coil problem that should be fixed before it gets worse or affects other circuits.
What does JLG Telehandler error code 33240 mean?
This code is about the UGM (a controller managing gear and drivetrain outputs) losing continuity to the transmission C control coil, the solenoid or coil responsible for engaging one of the gear selections in a powershift transmission configured for 4F/3R (4 forward, 3 reverse) operation.
When the UGM sees an open circuit at output J1-10, it assumes the coil or its wiring can't be trusted to shift reliably, so it shuts that output down entirely. Rather than letting the operator select a gear that might not engage correctly, the system restricts gear selection to 1st, 2nd, and 3rd only until the fault is cleared and power is cycled.
The flashing gear selection symbol on the LCD is the operator's visual cue that something is wrong with gear selection, even if the machine still drives normally in the available gears.
What triggers a JLG Telehandler 33240 code?
The UGM sets this fault when a transmission configuration of powershift is configured, a gear selection of 4F/3R is configured, and the UGM detects an open circuit at output J1-10 (transmission C control coil).
Common causes of 33240
- Open circuit in the wiring harness between the UGM and the transmission C control coil, often from a broken wire, chafed insulation, or a pulled connector
- Failed or open-wound transmission C control coil itself, unable to maintain a complete circuit
- Corroded, loose, or disconnected connector pins at the UGM output J1-10 or at the coil connector
- Damaged or degraded connector or terminal preventing continuity even when wires look intact
How to troubleshoot JLG Telehandler 33240: first checks
- Inspect the wiring harness from UGM output J1-10 to the transmission C control coil for visible damage, chafing, or broken conductors
- Check the connector at the transmission C coil and at the UGM for corrosion, bent pins, or loose terminals, and make sure both are fully seated
- Test continuity across the coil itself with the connector disconnected to rule out an internal open winding in the coil
- Verify the transmission configuration settings (powershift, 4F/3R) are correct for the machine, since this fault only sets under that specific configuration
- Look for other codes or symptoms tied to the same harness section, since one open circuit sometimes points to a bigger chafe or connector problem nearby
How the code clears
This fault latches until the machine is power cycled. After repairing the open circuit, whether it's a wiring repair, connector cleaning/reseating, or coil replacement, cycle machine power to clear the fault and confirm the gear selection symbol stops flashing and 4th gear becomes selectable again.
Frequently asked questions
What does JLG fault code 33240 mean?
It means the UGM controller detected an open circuit on the transmission C control coil output at J1-10, which controls a gear selection in a powershift transmission configured for 4F/3R. The controller disables that output and limits gear selection to 1st, 2nd, and 3rd.
Can I keep operating the telehandler with code 33240 active?
The machine will still drive, but only in 1st, 2nd, and 3rd gears since the transmission C coil output is disabled. It's not an immediate safety shutdown, but you're operating with reduced gear range until the open circuit is fixed.
Why is the gear selection symbol flashing on my JLG display?
That's the machine's way of telling you a gear selection issue is active. With code 33240, it flashes because the UGM has deactivated the transmission C control coil output due to the detected open circuit.
Will clearing code 33240 fix itself, or do I need to do something?
The fault latches until the machine is power cycled. Simply cycling the key won't fix an underlying open circuit though, you need to repair the wiring, connector, or coil first, then power cycle to clear the latch and confirm normal gear selection returns.
What parts should I check first for this fault?
Start with the wiring harness between the UGM output J1-10 and the transmission C control coil, then check both connectors for corrosion or loose pins, and finally test the coil itself for an open winding.
Does this fault only happen on certain transmission configurations?
Yes. It only sets when the machine is configured for a powershift transmission with a 4F/3R gear selection. If your machine uses a different transmission configuration, this specific fault condition won't apply.