JLG boom lifts (450AJ, 600AJ, 800AJ, 460SJ, 660SJ, 860SJ, 1250AJP, M450AJ, M600JP)
JLG error code 33139 — MAIN LIFT PILOT - PRESSURE FAILURE
Message on the display: MAIN LIFT PILOT - PRESSURE FAILURE · flash code 3/3
Code 33139 occurs in machines: JLG 1250AJP, 1100S, 1100SJP, 450AJ SII, 510AJ.
blocking fault
The UGM detected pressure on the main lift pilot line when there is is to be no pressure. Machine placed in retrieval mode to bring booms to rests. Fault cleared with power cycle.
Description from the JLG service manual, in the original wording.
Possible causes
The manual does not list the causes for this code: the service technician establishes them during diagnosis of the machine.
Checks from the manual
- Verify correct pressures on the main lift pilot circuit per the hydraulic schematic.
What service does
A qualified service technician reads the code with the manufacturer's diagnostic tools, finds the cause, clears the code and carries out a function test.
Source: JLG Service and Maintenance Manuals: 600AJ (3121201), 800AJ (3120858), 460SJ, 860SJ, 1250AJP (3122581800), M450AJ (3121829), M600JP (3121711), Diagnostic Trouble Codes tables.
The descriptions are quoted from the manufacturer's service documentation and are for guidance only. Clearing codes, calibrations and repairs are carried out by a qualified service technician according to the manual for the specific serial number. A machine with an active blocking code must not be used until the cause has been removed.
Does code 33139 not go away?
RK Rental services JLG lifts at our workshop or on site at the customer's premises (construction site, factory, warehouse). We read the code, remove the cause and select the parts by serial number.