JLG Articulating Boom Lift 33 Fault Code: Driver Problem
Also called Alternator Power Short to Ground, Aux Power Open Circuit, Aux Power Short to Battery, Aux Power Short to Ground, Basket Down Override Open Circuit, Basket Down Override Short to Battery, Basket Down Override Short to Ground, Basket Up Override Open Circuit, Basket Up Override Short to Battery, Basket Up Override Short to Ground, Cold Start Advance Solenoid Open Circuit, Cold Start Advance Solenoid Short to Battery, Cold Start Advance Solenoid Short to Ground, Common Short to Battery or Open Circuit Procedure, Common Short to Ground Procedure, Contactor Coil is Short-Circuited, Driver is Short-Circuit, Electric Pump Open Circuit, Electric Pump Short to Battery, Electric Pump Short to Ground, Engine Coolant Temperature (EOT) Sensor High Voltage, Generator Set/Welder Open Circuit, Generator Set/Welder Short to Battery, Generator Set/Welder Short to Ground, Glow Plug Open Circuit, Glow Plug Short to Battery, Glow Plug Short to Ground, Ground Alarm Open Circuit, Ground Alarm Short to Battery, Ground Alarm Short to Ground, Head Tail Light Open Circuit, Head Tail Light Short to Battery, Head Tail Light Short to Ground, Horn Open Circuit, Horn Short to Battery, Horn Short to Ground, Hour Meter Short to Battery, Hour Meter Short to Ground, Left Forward Drive Pump Open Circuit, Left Forward Drive Pump Short to Battery, Left Forward Drive Pump Short to Ground, Left Reverse Drive Pump Open Circuit, Left Reverse Drive Pump Short to Battery, Left Reverse Drive Pump Short to Ground, Main Dump Open Circuit, Main Dump Short to Battery, Main Dump Short to Ground, Main Lift Auxiliary Power Unit Pilot Valve Open Circuit, Main Lift Auxiliary Power Unit Pilot Valve Short to Battery, Main Lift Auxiliary Power Unit Pilot Valve Short to Ground, Main Lift Enable Open Circuit, Main Lift Enable Short to Battery, Main Lift Enable Short to Ground, Main Lift Pilot Pressure Failure, Main Lift Pilot Pressure Switch Failure, Main Telescope Flow Control Short to Battery, Main Telescope Flow Control Short to Ground, Main Telescope Flow Control Valve Open Circuit, Main Telescope In Open Circuit, Main Telescope In Short to Battery, Main Telescope In Short to Ground, Main Telescope Out Open Circuit, Main Telescope Out Short to Battery, Main Telescope Out Short to Ground, No Main Lift Pilot Pressure, PVG Valve Enable Open Circuit, PVG Valve Enable Short to Battery, PVG Valve Enable Short to Ground, Parking Brake Open Circuit, Parking Brake Short to Battery, Parking Brake Short to Ground, Restricted to Transport - Axle Lockout Valve Short to Battery or Open Circuit, Restricted to Transport - Parking Brake Short to Battery, Right Forward Drive Pump Open Circuit, Right Forward Drive Pump Short to Battery, Right Forward Drive Pump Short to Ground, Right Reverse Drive Pump Open Circuit, Right Reverse Drive Pump Short to Battery, Right Reverse Drive Pump Short to Ground, Start Solenoid Open Circuit, Start Solenoid Short to Battery, Start Solenoid Short to Ground, Swing Left Open Circuit, Swing Left Short to Battery, Swing Right Open Circuit, Swing Right Short to Battery, Throttle Actuator Open Circuit, Throttle Actuator Short to Battery, Throttle Actuator Short to Ground, Tower Lift Auxiliary Power Unit Pilot Valve Open Circuit, Tower Lift Auxiliary Power Unit Pilot Valve Short to Battery, Tower Lift Auxiliary Power Unit Pilot Valve Short to Ground, Tower Lift Auxiliary Power Unit Pilot Valve Stuck Open, Tower Lift Enable Open Circuit, Tower Lift Enable Short to Battery, Tower Lift Enable Short to Ground, Tower Lift Enable Stuck Open, Tower Telescope Auxiliary Power Unit Pilot Valve Open Circuit, Tower Telescope Auxiliary Power Unit Pilot Valve Short to Battery, Tower Telescope Auxiliary Power Unit Pilot Valve Short to Ground, Tower Telescope Auxiliary Power Unit Pilot Valve Stuck Open, Tower Telescope Enable Open Circuit, Tower Telescope Enable Short to Battery, Tower Telescope Enable Short to Ground, Tower Telescope Enable Stuck Open, Traction Motor at Current Limit, Two Speed Open Circuit, Two Speed Short to Battery, Two Speed Short to Ground
Driver Problem · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Fault code 33 is a priority 6 communicated fault on JLG articulating boom lifts covering a large group of driver circuit problems: outputs and inputs across drive pumps, dump valves, parking brake, lighting, horn, glow plugs, basket and jib functions, tower and telescope functions, and more, each shorted to ground, shorted to battery, or open circuit. The exact affected component is identified by the specific fault description shown on the analyzer, not by the number 33 alone.
Medium severity. Priority (6) faults are communicated to the analyzer but many do not stop the machine outright. Severity depends heavily on which specific circuit is affected: a parking brake or main dump fault has real safety weight, while a horn or hour meter fault is mostly informational. Treat each occurrence based on the exact description shown.
What does JLG Articulating Boom Lift error code 33 mean?
Fault code 33 is not one single failure. It is a shared diagnostic code JLG uses for a whole family of driver circuit faults across the machine's electrical system. Each entry (drive pumps, main dump, parking brake, glow plugs, horn, lights, basket controls, jib controls, tower and telescope functions, and more) triggers under this same code number but with its own specific description text on the analyzer.
For every affected circuit, the controller is watching the driver output using analog feedback. An open circuit is detected when that feedback reads too high while the output is commanded off. A short to battery is detected when the feedback reads battery voltage while the output is commanded off. A short to ground is detected when the feedback reads low while the output is commanded on.
Because so many different components share this code, the real diagnostic work starts by reading the exact fault description on the display or analyzer, since that tells you which pin, module, or component is actually implicated.
Common causes of 33
- A failed component internally shorting to battery voltage, which is described as a frequent cause of short to battery and open circuit conditions.
- A failed component internally shorting to ground, described as a frequent cause of short to ground conditions.
- Loose, damaged, or corroded connector pins at the component or module connector.
- Moisture inside a connector, which can create an unintended path to ground or battery.
- Wiring damage between the module and the affected component (chafing, pinching, or breaks) leading to an open circuit or short.
- On machines with a chassis module, drive pump driver faults that only occur when that module is present.
- Configuration-specific circuits (glow plugs, dual-fuel LP lock and start assist, ground alarm, generator set/welder, headlights, electronic leveling, gravity lift down, oscillating axles) faulting only when that option is actually configured on the machine.
How to troubleshoot JLG Articulating Boom Lift 33: first checks
- Read the exact fault description shown on the analyzer or display. Code 33 covers dozens of distinct circuits, so the specific wording (for example, main dump short to battery, or parking brake open circuit) tells you which component and pins to inspect.
- Inspect the connector for the identified component or module pin. Look for moisture inside the connector body and for pins that are loose, damaged, or corroded.
- Trace the wiring between the controller and the affected component for chafe points, pinched sections, or breaks, especially near articulation points or moving booms.
- Check whether the affected function is tied to a machine option (chassis module, glow plugs, dual-fuel engine, ground alarm, headlights, electronic leveling, gravity lift down, oscillating axles). If the option is not installed or not configured, that fault should not normally be active.
- Confirm the component itself is not internally shorted. A failed solenoid, valve coil, light, or sensor shorting to battery or ground is a common root cause behind the driver fault.
- Verify the component's power source. JLG notes that power does not always come directly from the battery. Some components run through the ground module or are effectively their own module, such as main boom angle sensors and PVG valves.
How the code clears
No separate clearing step is listed beyond correcting the underlying wiring or component fault. Since this is a communicated fault based on analog feedback from the driver circuit, it should stop being reported once the open circuit, short to ground, or short to battery condition is physically repaired. No reset procedure beyond the repair itself is described.
Frequently asked questions
What does JLG fault code 33 actually mean?
It is a general driver circuit fault code covering many possible components. The controller has detected either an open circuit, a short to battery, or a short to ground on a specific input or output pin. The exact component involved is named in the fault description shown on the analyzer, not by the number 33 by itself.
Is fault code 33 dangerous to keep operating with?
It depends entirely on which circuit is affected. A parking brake, main dump, or drive pump fault can affect machine control and should be treated seriously. A horn, hour meter, or lighting fault is lower risk but still worth fixing. Always check the specific description text before deciding.
Why does my fault only show up on certain machines?
Several of the faults under code 33 are tied to specific configurations, such as machines with a chassis module, glow plug equipped engines, dual-fuel LP systems, ground alarm option, headlights option, electronic leveling systems, gravity lift down, oscillating axles, or the 1250AJP model specifically. If that option is not installed, the related fault will not apply to your machine.
How do I tell a short to ground apart from a short to battery on this code?
JLG detects short to ground when the analog feedback reads low while the output is commanded on. Short to battery is detected when the feedback reads battery voltage while the output is commanded off. Open circuit is detected when the feedback reads too high while the output is commanded off.
What should I check first when I get this fault?
Start with the connector for the specific component named in the fault description. Look for moisture inside the connector and for loose, damaged, or corroded pins, since JLG identifies these as frequent causes alongside an internally shorted component.
Does fixing the wiring clear the fault automatically?
No separate reset procedure is listed. The fault is based on live feedback from the driver circuit, so once the open circuit, short to ground, or short to battery condition is physically repaired, the fault should stop being reported.
Can this code appear for something as simple as a horn or light?
Yes. The same code 33 numbering covers safety-critical circuits like parking brake and main dump as well as lower-stakes circuits like the horn, head/tail lights, and hour meter. The specific description on the analyzer is what tells you which one you are dealing with.