JLG ES series scissor lifts (1930ES, 2030ES, 2630ES, 2646ES, 3246ES)
JLG error code 33303 — NEGATIVE SUPPLY - SHORT TO GROUND
Message on the display: NEGATIVE SUPPLY - SHORT TO GROUND
Code 33303 occurs in machines: JLG ES series, 1932RS, 6RS, 3248RS, 10RS.
blocking fault
Drive, Lift and Steer Prevented
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
- At power-up, the System Module detected an external short on J1-12, J1-17, J2-14 or J2-15. Normally these pins are grounded by the System Module. Since the external ground may compromise integrity, all functions will be prevented.
- ZAPI - HEALTH (Status LED) - ON
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 Manual, ES series (Diagnostic Trouble Codes section).
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 33303 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.