JLG Troubleshooting – Aerial Lifts

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Fix those codes!

We understand every JLG aerial lift encounters a problem once in a while. That’s why we’ve come up with a troubleshooting page for you, this one specifically for JLG troubleshooting. Listed below are some popular JLG scissor lifts and their corresponding error codes, although not restricted to these models. If you ever need JLG replacement parts or accessories, you can visit our website by clicking here.


JLG troubleshooting 1930ES


Popular JLG Scissor Lifts:

  • JLG 1930ES
  • JLG 2030ES
  • JLG 2032ES
  • JLG 2630ES
  • JLG 2632ES
  • JLG 2646ES
  • JLG 3246ES



JLG troubleshooting diagnostic codes:

If the number starts with….. it’s a

2-1 – Power Up Problem

2-2 – Platform Controls

2-3 – Ground Controls

2-5 – Function Prevented

3-1 – Line Contactor Open Circuit              6-6 – Communication

3-2 – Line Contactor Short Circuit               6-7 – Accessory

3-3 – Ground Output Driver                        7-7 – Electric Motor

4-2 – Thermal Output                                 8-1 – Tilt Sensor

4-4 – Battery Supply                                   8-2 – Platform Load Sense



Popular JLG Troubleshooting Codes

  • Error Code: 212

Fault Message: Faulty Keyswitch

Description: Both platform and ground modes are selected simultaneously.

Check: Key switch function, Check wiring to key switch function.


  • Error Code: 221

Fault Message: Horn Permanently Selected

Description: The horn switch was closed during power-up in platform mode.

Check: Check if the horn is damaged, obstructed or jammed.


  • Error Code: 226

Fault Message: Accelerator Faulty

Description: The joystick signal is outside the acceptable range of 0.5V – 4.5V.

Check: Center joystick and check to see if a power cycle will clear DTC.


  • Error Code: 231

Fault Message: Function Problem – Lift Permanently Selected

Description: The ground control box lift switch was closed up or down, during power up in ground mode.

Check: Check if the lift switch is obstructed or jammed.


  • Error Code: 233

Fault Message: Function Problem – Brake Release Permanently Selected

Description: The manual brake release switch was closed during power-up.

Check: Check if brake release switch is obstructed or jammed.


  • Error Code: 251

Fault Message: Elev Angle Sensor Faulty

Description: Elevation angle sensor input voltage is outside the acceptable range of 0.10V – 4.50V.

Check: Check that the platform elevation sensor is securely mounted and undamaged, Check the elevation sensor wiring.


  • Error Code: 314

Fault Message: Auxiliary Circuit – Open Relay

Description: The auxiliary relay did not close when energized.

Check: Check the auxiliary relay coil and associated wiring.


  • Error Code: 441

Fault Message: Battery Voltage Too Low

Description: The power module momentarily measure battery voltage under 14.5V.

Check: Recharge batteries or check for damaged batteries.


  • Error Code: 775

Fault Message: Open Circuit Field Wiring

Description: Drive, steer, and lift prevented.

Check: The system module applied field current, but could regulate the desired current. The situation is caused by improper field wiring or a damaged motor.




JLG troubleshooting

Need JLG aerial lift parts?  With thousands of parts in stock, quick shipping and great customer service, Intella Liftparts can help. You can also check out our YouTube channel here for how-to videos, product overviews, and other great clips.

Post by Intella Liftparts

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8 thoughts on “JLG Troubleshooting – Aerial Lifts”

  1. Hi i have a older jlg 2030 and it keeps tripping out when you use the top controls. I thought it may have been the batteries and it seamed to work for about 1 hr then it started doing the same thing. It resets then goes for a short time then trips out and all the lights start flashing on the control box. It would be great if you had some idea on what is going on.

    Trevor de Git
  2. Mine is throwing a code 314 auxiliary relay….?

  3. Need help please, I have a 2000 year model E300AJP aerial lift. The wheels will not move forward or backward and they will not turn left or right. A technian has looked at it and it is not throwing any codes. All you hear when you try to move or steer it is the pump motor whining up. All other function work as the should. Please any help would be greatly appreciated. The lift is inside a building and can’t be loaded on a truck

  4. our JLG 2632ES scissor lift threw a 311 code. can you please advise me what this means and what we can do to fix it? Thanks

    Tyrone Wnuk
  5. Have flashing yellow 2than 3 Than red 2flashes