JLG boom lifts (450AJ, 600AJ, 800AJ, 460SJ, 660SJ, 860SJ, 1250AJP, M450AJ, M600JP)
JLG error code 4375 — WATER IN FUEL
Message on the display: WATER IN FUEL
Code 4375 occurs in machines: JLG 1250AJP, 400S, 460SJ.
blocking fault
The UGM received water in fuel trouble code from the Engine Control Module. The engine has detected an unacceptable amount of water in the fuel or there is an issue with the water in fuel sensor. Machine will shutdown the engine. ECM will clear fault once issue is no longer detected. UGM will clear fault on power cycle and ECM is no longer reporting
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
- Refer to Engine Manufacture's Take Action for Repair procedure in Diagnostic Trouble Code list using the SPN:FMI provided to diagnose and repair (Engine Trouble Code SPN = 97). Check for Water in fuel filter separator or water in fuel sensor for malfunction.
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 4375 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.