JLG Telehandler 33185 Fault Code: UGM Output Drivers - Main Lift Down Valve - Short to Ground
UGM Output Drivers - Main Lift Down Valve - Short to Ground · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Code 33185 sets when the UGM (the machine's controller module) detects a short to ground at the main lift down valve output (J2-22), or loses current feedback on the lift return input (J3-2). The controller responds by disabling that output and shutting down both lift up and lift down function until the machine is power cycled. It triggers a machine system distress indicator.
High severity. This fault disables both lift up and lift down function, not just lift down. That means the boom cannot be raised or lowered until the fault is diagnosed and the machine is power cycled. Any load currently on the boom should be treated with caution since normal lowering control is not available.
What does JLG Telehandler error code 33185 mean?
Code 33185 points to a problem in the electrical circuit that controls the main lift down valve, which is the solenoid valve responsible for allowing the boom to lower. The UGM (the machine's control module) constantly monitors the output driver circuit for this valve. If it detects that the circuit has shorted to ground, or if it loses current feedback on the lift return signal, it flags the condition internally to help determine whether this is the true cause of the fault.
When this happens, the controller does two things automatically: it deactivates the output at J2-22 (the main lift down valve driver) and it decouples the current feedback input at J3-2 (lift return). Because that feedback circuit is shared logic for both directions, disabling it takes out lift up function as well as lift down. This is a protective measure to prevent uncontrolled valve operation from a damaged or shorted circuit.
The fault is described as causing machine system distress, meaning it is treated as a significant operational fault, not a minor advisory. It stays active, or latched, until the machine is power cycled, even if the underlying short clears itself.
What triggers a JLG Telehandler 33185 code?
The UGM sets this code when it detects a short to ground at the main lift down valve output (J2-22), or when it detects a current feedback lost condition at the lift return input (J3-2) and its internal logic determines this condition is the cause of the fault.
Common causes of 33185
- A short to ground in the wiring harness feeding the main lift down valve output (J2-22), often from chafed insulation, pinched wiring, or water intrusion.
- A failed or internally shorted main lift down valve solenoid coil.
- A loss of current feedback on the lift return circuit (J3-2), which can result from a broken wire, corroded connector, or loose terminal in that circuit.
- Damage inside the UGM's output driver stage itself, if the short is severe or has occurred repeatedly.
How to troubleshoot JLG Telehandler 33185: first checks
- Inspect the wiring harness and connectors around the main lift down valve (J2-22) for chafing, pinched wire, corrosion, or moisture intrusion.
- Check the lift return circuit at J3-2 for loose, corroded, or broken connections that could cause a current feedback lost condition.
- With power removed, check the main lift down valve coil for a short to ground using a multimeter, comparing resistance to ground against expected isolation.
- Inspect connector pins at the UGM for bent, backed-out, or corroded pins that could cause an intermittent or hard short.
- Look over the harness routing for signs of rubbing against frame components or pinch points near the lift valve area.
How the code clears
This fault latches until the machine is power cycled. Cycling the key off and back on will attempt to clear the fault, but if the underlying short to ground or current feedback loss is still present, the code will set again as soon as the UGM re-checks the circuit. No separate clearing step is listed beyond the power cycle.
Frequently asked questions
What does JLG fault code 33185 mean?
It means the machine's UGM controller detected a short to ground on the main lift down valve output circuit, or lost current feedback on the lift return circuit, and shut down both lift up and lift down function as a protective response.
Why does this code disable lift up as well as lift down?
Because the current feedback input at J3-2, which the UGM decouples in response to this fault, is shared logic used to monitor both lift directions. Disabling it to protect against a shorted circuit takes out both lift up and lift down function together.
Can I clear code 33185 by just cycling the key?
You can attempt it since the fault is latched until power cycle. But if the short to ground or current feedback loss is still present in the circuit, the code will return as soon as the UGM detects the condition again.
Is it safe to keep operating the telehandler with this code active?
No. With lift up and lift down disabled, you have no way to safely control boom height. Treat it as a stop-and-diagnose situation, especially if there is a load on the boom.
What wiring or components should a technician check first for code 33185?
Start with the main lift down valve output circuit at J2-22 and the lift return current feedback circuit at J3-2. Check for chafed or pinched harness sections, corroded connectors, and test the valve coil for an internal short to ground.
Does this fault indicate a bad valve or a bad controller?
It can be either. Most often the cause is a wiring short or a failed valve coil, but if those check out fine, the output driver stage inside the UGM itself should be evaluated.