Diagnostics
JLG Boom Lift Fault Codes: Meanings, Causes & Fixes
In-depth, plain-English guides to JLG Boom Lift fault codes and error codes. Each guide covers what the code means, what triggers it, the most common causes, and the first things to check before you call the dealer.
- 14Overcrank
- 21Problems with Foot Switch
- 22Engine Starting System Fault
- 23Problems with Boom Function Selection
- 31Contactor Did Not Close When Energized
- 33Contactor Coil is Short-Circuited
- 55Problems with Vehicle Speed or the Encoder
- 66Problems with the CAN Bus
- 77Problems with a Motor
- 99Problems with the Controller
Safety-critical: confirm before use
Torque, lifting, and load-chart values are safety-critical. Never operate from these figures alone. Confirm against the official manual and a qualified technician.