JLG Scissor Lift 9 Fault Code: Coolant Temperature
Also called Drive Prevented - Elevated Above Drive Cutout Height
Coolant Temperature · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Fault code 9 on JLG scissor lifts (SPN 110 / FMI 2) covers two distinct conditions bundled under the same code: a coolant temperature sensor fault (short circuit or cable break) and a drive-prevented condition that occurs when the platform is elevated above the calibrated drive cutout height. Diagnosis depends on which description applies to your fault log.
Medium severity. This code is not an immediate stop-work emergency by itself, but it disables an associated monitoring function (for the sensor fault) or blocks drive function (for the elevation cutout condition) until resolved. Treat it as something to diagnose before continuing normal operation.
What does JLG Scissor Lift error code 9 mean?
Fault code 9 (SPN 110 / FMI 2) on JLG scissor lifts appears in two forms depending on the description logged. The first is a Coolant Temperature sensor fault, which falls under the Sensors fault group. This means the controller detected a short circuit or a broken cable at the coolant temperature sensor circuit, and as a result the monitoring function tied to that sensor is de-activated.
The second form is a Drive Prevented condition, which occurs when the platform has been raised above the calibrated cutout height for driving. Scissor lifts use an elevation sensor to determine platform height, and many machines are programmed to prevent or limit drive function once the platform rises above a set threshold, as a stability and tip-over safety measure.
Both conditions share the same fault code number but point to very different systems: one is an electrical sensor wiring issue, the other is a lifting/stability interlock function tied to platform height and machine configuration.
Common causes of 9
- Short circuit at the coolant temperature sensor cable or connector.
- Cable break (open circuit) in the coolant temperature sensor wiring.
- Elevation angle sensor not securely mounted, causing an inaccurate height reading.
- Incorrect MARKET configuration setting under ANALYZER→MACHINE SETUP, which affects the calibrated drive cutout height.
How to troubleshoot JLG Scissor Lift 9: first checks
- Inspect the coolant temperature sensor cable for visible damage, chafing, or a break along its length.
- Check the sensor connector and pins for corrosion, looseness, or contamination, and clean or reseat as needed.
- Check the fault limits programmed for the coolant temperature sensor to confirm they match expected values.
- If the platform is showing as elevated above cutout height, inspect the elevation angle sensor for secure mounting; a loose sensor can send a false height reading.
- Verify the ANALYZER→MACHINE SETUP→MARKET configuration is set correctly for your machine and region.
How the code clears
No separate clearing step is listed for either condition. For the sensor fault, correcting the wiring or connector issue and confirming the sensor operates within its programmed fault limits should allow the fault to clear on its own. For the drive-prevented condition, lowering the platform below the calibrated cutout height, or correcting the elevation sensor mounting and market configuration, should restore drive function.
Frequently asked questions
Why does my JLG scissor lift show fault code 9 for coolant temperature?
This points to a fault at the coolant temperature sensor circuit, most likely a short circuit or a cable break. Check the sensor cable and connector first, then check the sensor itself and replace it if needed.
Why won't my scissor lift drive when the platform is raised?
JLG scissor lifts prevent or limit driving once the platform is elevated above a calibrated cutout height, as a stability safety feature. Fault code 9 can log this drive-prevented condition when that threshold is exceeded.
Can a loose sensor cause the drive-prevented version of this fault?
Yes. If the elevation angle sensor is not securely mounted, it can send an inaccurate height signal, which may falsely trigger the drive cutout even if the platform is not actually above the real cutout height.
Is fault code 9 dangerous to keep operating with?
It should not be ignored. The sensor version disables an associated monitoring function, and the drive-prevented version is a built-in stability safeguard. Both should be diagnosed before resuming normal work.
What is the MARKET setting and why does it matter for this fault?
The MARKET configuration is found under ANALYZER→MACHINE SETUP on the machine's diagnostic menu. It affects region-specific settings, including the calibrated drive cutout height, so an incorrect setting here can cause the drive-prevented condition to trigger incorrectly.
Do I need to replace the coolant temperature sensor every time this code appears?
Not necessarily. Start by checking the cable and connector for damage or corrosion. Only replace the sensor if those checks come back clean and the sensor still fails to operate within its programmed fault limits.