JLG Scissor Lift 8 Fault Code: Oil Pressure
Also called Functions Locked Out - System Powered Down
Oil Pressure · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Code 8 (SPN 100 / FMI 2) on JLG scissor lifts covers two distinct situations: an oil pressure sensor circuit fault (short or open cable) or a normal low-power lockout after the machine sits idle for 2 hours. Check which condition applies before assuming a sensor failure.
Medium severity. If this is the low-power lockout, it is purely informational and clears with a power cycle. If it is a genuine sensor circuit fault, the related oil pressure monitoring function is disabled, which is a real diagnostic gap that should be fixed before relying on the machine for extended use.
What does JLG Scissor Lift error code 8 mean?
Fault code 8 on JLG scissor lifts (SPN 100 / FMI 2) has two separate descriptions tied to it: 'Functions Locked Out - System Powered Down' and 'Oil Pressure'. These point to two different root situations that share the same code number.
The oil pressure side relates to a sensor fault, meaning the controller detects a short circuit or a broken cable at the oil pressure sensor entry. When this happens, the monitoring function tied to that sensor is deactivated, so the system can no longer watch oil pressure the way it normally would.
The 'Functions Locked Out' side is different: it describes a low-power state the control system enters after the machine has sat without activity for 2 hours. This is a battery-saving feature, not a failure, and normal operation should return after a power cycle.
Common causes of 8
- Short circuit at the oil pressure sensor cable or connector
- Cable break (open circuit) at the oil pressure sensor entry
- Failed oil pressure sensor itself
- Machine left without activity for 2 hours, causing the control system to enter a low-power state to preserve battery charge
How to troubleshoot JLG Scissor Lift 8: first checks
- Determine which condition applies: has the machine been idle for an extended period, or is this happening during active use?
- If idle-related, cycle power off and back on and confirm normal operation resumes
- Check battery charge level and general condition, since a weak or degraded battery can be tied to the low-power lockout behavior
- Inspect the oil pressure sensor cable for visible damage, chafing, or corrosion at connectors
- Check the oil pressure sensor itself and replace if it tests faulty
- Check the fault limits programmed for the sensor to confirm they match expected values
How the code clears
For the low-power lockout, a power cycle should restore normal operation; if it does not, check battery charge and condition. For the oil pressure sensor fault, no separate clearing step is listed beyond fixing the cable or sensor, after which the monitoring function should reactivate on its own.
Frequently asked questions
What does JLG fault code 8 mean?
It can mean one of two things: either the oil pressure sensor circuit has a short or a broken cable, or the machine has entered a low-power lockout state after sitting idle for 2 hours. You need to check which situation applies.
Why did my scissor lift lock out all functions?
If the machine sat unused for 2 hours, the control system automatically enters a low-power state to save battery charge. This locks out functions until you power cycle the machine.
Will cycling the key fix code 8?
If the cause is the low-power lockout, yes, normal operation should resume after a power cycle. If the cause is a genuine oil pressure sensor fault, a power cycle will not fix it and the code will likely return.
Is it safe to keep operating with code 8 active?
If it's the sensor fault, the oil pressure monitoring function is disabled, meaning you lose that safety check. It's best to get the cable and sensor inspected before continued use.
What should I check first if code 8 keeps coming back after a power cycle?
Check the battery charge and condition first, since a weak battery can contribute to repeated low-power lockouts. If the battery checks out, inspect the oil pressure sensor cable and connector for damage.
Does code 8 always mean a sensor is bad?
No. It can also simply mean the machine powered down on its own after being idle. Only inspect or replace the sensor if you've ruled out the low-power lockout explanation.