JLG Scissor Lift 2346 Fault Code: Ground Controls - Boom Angle Sensor - Not Responding
Ground Controls - Boom Angle Sensor - Not Responding · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Fault code 2346 sets when JLG's ground control system detects the boom angle sensor is not responding while the main lift valves are actively commanded. It locks the boom angle display at a fixed value of 99 and restricts lift functions until the machine is power cycled.
High severity. This fault disables normal boom angle feedback and can shut down or derate lift up capability. It should be treated as a stop-and-diagnose issue before continued operation, since the controller is actively protecting against unmonitored boom movement.
What does JLG Scissor Lift error code 2346 mean?
Fault code 2346 is described by JLG as 'Ground Controls - Boom Angle Sensor - Not Responding.' The boom angle sensor tells the machine's controller what angle the boom or scissor structure is at, which is used to manage lift functions safely and accurately. When the controller commands a lift up or lift down function but sees no meaningful change from this sensor, it assumes the sensor has failed or lost communication.
When this fault sets, the operator's cabin display locks in a fixed boom angle value of 99, which is not a real angle reading but a flag telling the operator and technician that the sensor input is not trustworthy. The system also blocks any attempt to calibrate the boom angle sensor while this fault is active, displaying a 'boom angle: calibration fail' message.
Because JLG cannot verify actual boom position, the controller ignores all hydraulic function requests coming from the platform module. If a platform is attached or platform mode is active, lift up is fully deactivated and inhibited. If no platform is detected, the machine instead derates the maximum lift up rate according to a lift up derate value stored in the constant data tables, rather than shutting it down completely.
What triggers a JLG Scissor Lift 2346 code?
The fault sets when either the J2-11 main lift up valve or the J2-22 main lift down valve is actively commanded at a current of at least 900 mA for a period of at least 4 seconds while the engine is running, and the boom angle sensor shows no appreciable change, defined as less than 0.5 degrees (this threshold is adjustable in constant data). This fault will not be reported while the boom angle sensor calibration procedure is being performed.
Common causes of 2346
- Boom angle sensor has failed internally and no longer produces a changing signal when the boom actually moves.
- Wiring or connector fault between the boom angle sensor and the ground control module, causing a stuck or flat signal.
- Mechanical failure or disconnection linking the sensor to the boom structure, so the sensor itself is not moving even though the boom is.
- Main lift up (J2-11) or main lift down (J2-22) valve is being commanded and drawing sufficient current, but no matching angle change is detected, which points to a feedback loop break rather than a valve problem itself.
- Sensor calibration was never completed or was left in a bad state, though note this fault is suppressed during the calibration process itself.
How to troubleshoot JLG Scissor Lift 2346: first checks
- Check the cabin display for the fixed boom angle value of 99, which confirms this fault is active rather than a normal angle reading.
- Inspect the boom angle sensor's wiring harness and connectors for corrosion, looseness, or damage, especially near pivot points where wear is common.
- Verify the physical linkage or mounting of the boom angle sensor to the boom structure to confirm it is intact and moves freely when the boom is raised or lowered.
- With the engine running, carefully command a small lift up or lift down motion and watch whether the boom angle reading changes at all on the display or via diagnostic tool, keeping personnel clear of the boom and platform area.
- Check whether platform mode is active or a platform is attached, since this changes whether lift up is fully inhibited or just derated, which affects what symptoms the operator will report.
- Confirm no one is attempting to run boom angle sensor calibration during testing, since the fault is intentionally suppressed during that procedure and could mask a real problem.
How the code clears
This fault latches until a power cycle. After confirming and correcting the underlying wiring, sensor, or mechanical issue, cycle machine power off and back on to clear the fault. No separate clearing step is listed beyond the power cycle.
Frequently asked questions
What does fault code 2346 mean on a JLG scissor lift?
It means the ground control system commanded a main lift up or lift down valve but did not see the boom angle sensor value change as expected, so the controller treats the sensor as not responding and restricts lift functions for safety.
Why does my JLG display show a boom angle of 99?
A boom angle reading of 99 is not a real angle. It is a fixed placeholder value the controller displays when fault code 2346 is active, telling you the real sensor signal cannot be trusted.
Why can't I calibrate the boom angle sensor when this fault is active?
JLG's control logic disallows boom angle sensor calibration while fault 2346 is set and will show a 'boom angle: calibration fail' message. The sensor problem needs to be fixed first, then calibration can be attempted again.
Will my scissor lift still lift with fault code 2346 active?
It depends on whether a platform is attached or platform mode is active. If so, lift up is deactivated and inhibited entirely. If not, the machine instead derates the maximum lift up rate using a value from the constant data tables rather than stopping it completely.
How do I clear fault code 2346 after fixing the problem?
This fault latches until a power cycle, meaning you need to turn the machine off and back on after correcting the wiring, sensor, or mechanical issue causing the lost signal.
What triggers fault code 2346 to set in the first place?
It sets when either the main lift up valve (J2-11) or main lift down valve (J2-22) is commanded at 900 mA or more for at least 4 seconds with the engine running, and the boom angle sensor shows less than 0.5 degrees of change, which is an adjustable threshold in the constant data.
Does this fault happen during normal sensor calibration?
No. JLG's logic specifically will not report this fault while the boom angle sensor calibration procedure is being run, so it should only appear during normal lift operation.