JLG Telescopic Boom Lift 35 Fault Code: Brake Pressure Problem
Also called Help Comment - APU Active, Intake Air Temperature (lAT) Sensor High Voltage, Speed Warning (With Thrust Mode Operation)
Brake Pressure Problem · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Fault code 35 on JLG telescopic boom lifts (SPN/FMI 14) covers a functional fault warning that can mean the brake pressure did not lock or release as expected, or that machine revolutions went above the top speed limit while thrust mode was active. On the analyzer this shows as flash code 3-5 for the brake pressure version. It is a warning-level code, but it touches both braking and travel speed control, so treat it as a stop-and-check item.
High severity. This code is logged as a functional fault warning, not a shutdown fault, but it directly involves brake pressure and travel speed limiting. A brake that fails to lock or release, or a drive system running past its speed limit, is a safety-relevant condition. Diagnose before returning the machine to normal duty.
What does JLG Telescopic Boom Lift error code 35 mean?
Fault code 35 is reported under more than one description depending on the machine and function involved. In its speed-related form, it means the controller detected revolutions above the top revolution speed limit while the "thrust mode" function was active. This points to the drive or travel speed control system running faster than the limit allows during a specific operating mode.
In its brake-related form, the same code number is used to flag a brake pressure problem. There are two versions of this: brakes did not lock, meaning brake pressure did not clear when the brake valve was de-energized, or brakes did not release, meaning no brake pressure was detected when the pump motor was running and the brake valve was energized.
Because this single fault code spans both a speed-limit warning and a brake pressure warning depending on the model and fault group, the correct diagnosis path depends on which behavior the machine is actually showing: a speed/thrust issue or a brake lock/release issue.
What triggers a JLG Telescopic Boom Lift 35 code?
For the speed warning version, the code sets when revolutions go above the top revolution speed limit while thrust mode is active. For the brake pressure version, it sets when brake pressure fails to clear after the brake valve is de-energized (brakes did not lock), or when no brake pressure is detected while the pump motor runs and the brake valve is energized (brakes did not release). No other numeric thresholds are listed.
Common causes of 35
- Revolutions above the top revolution speed limit while thrust mode function is active (speed warning version).
- Brake pressure did not clear when the brake valve was de-energized, so the brakes did not lock as expected.
- No brake pressure detected when the pump motor was running and the brake valve was energized, so the brakes did not release as expected.
- Incorrect or drifted parameter, speed setting, or PID setting affecting speed control.
- Worn or damaged rods, actuator, or actuator cable affecting speed regulation.
- Speed sensor giving impulses at an incorrect speed, or an incorrect number of teeth being read by the sensor.
How to troubleshoot JLG Telescopic Boom Lift 35: first checks
- Confirm which fault behavior is actually present: a speed/thrust warning or a brake lock/release problem, since the help steps differ.
- For the speed warning: check the parameters, speed settings, and PID setting against expected values.
- Inspect rods, the actuator, and the cable to the actuator for wear, damage, or looseness; replace the actuator if required.
- Check the speed sensor for impulses at an incorrect speed and verify the number of teeth being read matches the correct setup.
- On vehicles, check for the possible presence of thrust mode being active when it should not be.
- For the brake pressure version, verify brake valve energizing and de-energizing operation and confirm whether pressure is present or absent as expected during both the lock and release phases.
- Check all wiring and connectors related to the brake valve and pump motor circuits for corrosion, looseness, or damage.
How the code clears
No separate clearing step or reset procedure is listed for this code. Clear the fault using the machine's standard fault-clear method after the underlying cause has been corrected, and confirm the fault does not return during a normal operating cycle.
Affected models and serial ranges
35 appears in our records across 1 JLG Telescopic Boom Lift models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| E600 | Serial range not listed in source records |
Frequently asked questions
What does JLG fault code 35 mean?
It is a functional fault warning that can indicate either a speed problem (revolutions above the top speed limit while thrust mode is active) or a brake pressure problem (brakes not locking or not releasing as expected), depending on the specific description logged.
Is fault code 35 the same as flash code 3-5?
Yes, for the brake pressure version. On the analyzer, flash code 3-5 indicates a brake pressure problem corresponding to this fault.
Can I keep operating the machine with fault code 35 active?
It is not recommended. Whether the issue is a speed limit warning during thrust mode or a brake pressure fault, both involve safety-critical systems for controlling and stopping the machine. Diagnose before continuing normal operation.
What is thrust mode in relation to this fault?
The listed cause for the speed warning version states that revolutions went above the top revolution speed limit while the thrust mode function was active. The help steps specifically direct checking for possible thrust mode on vehicles as part of diagnosing this.
What is the difference between brakes not locking and brakes not releasing under this code?
Brakes did not lock means brake pressure did not clear when the brake valve was de-energized. Brakes did not release means no brake pressure was detected when running the pump motor and energizing the brake valve. Both are listed causes under the brake pressure description for this code.
What should be checked first if this is a speed-related fault?
Start with parameters, speed settings, and the PID setting, then move on to inspecting rods, the actuator and its cable, and the speed sensor for incorrect impulses or tooth count issues.
Is there a reset procedure listed for fault code 35?
No reset procedure is listed for this code. Standard fault-clearing practice should be used once the underlying cause is found and corrected.