JLG Telehandler 99153 Fault Code: Hardware - LSI Faulty - Data Flash CRC Error
Also called LSI Faulty - Data Flash CRC Error
Hardware - LSI Faulty - Data Flash CRC Error · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Code 99153 means the Load Sensing Indicator (LSI) system has found a checksum error in its data flash memory and reported it over the CAN bus to the UGM or ground module. The machine responds as if the load moment cutout percent parameter has been reached, and operation is normally limited to creep mode via the LSI override switch until the issue is cleared.
High severity. This code puts the machine into a load cutout state and restricts operation to override/creep mode, which stops normal lifting work until resolved. It is not an immediate engine or fire hazard, but it directly affects load capacity protection, so it should be treated as a stop-and-diagnose condition rather than something to run through a shift.
What does JLG Telehandler error code 99153 mean?
Code 99153 fires when the LSI (Load Sensing Indicator) system detects a checksum error in its own data flash or system flash memory. The LSI is the module responsible for monitoring load moment and telling the machine when it is approaching or exceeding safe lifting limits. When its internal memory fails a checksum check, the module can no longer trust its own calibration or programming, so it flags the problem and sends a message over the CAN bus to the UGM (upper/universal gauge module or similar controller) or ground module.
Because the LSI can no longer be trusted to accurately judge load moment, the control system defaults to treating the situation as if the load moment cutout percent parameter has already been reached. Depending on how the machine is configured for its market, this triggers a load cutout condition. Normal lifting operation is blocked, and the operator can only move the machine using the LSI override switch, which puts it into a slow, creep-mode style operation intended for getting the machine to a safe position rather than continuing normal work.
This is fundamentally a hardware and data-integrity fault inside the LSI module itself, not a wiring or sensor input problem elsewhere on the machine. That is why the fix generally points toward the LSI unit itself rather than field wiring.
Common causes of 99153
- Internal data flash checksum error inside the LSI module, meaning the stored calibration or program data has become corrupted or unreadable
- System flash checksum error reported to the ground module, similar in nature but affecting the LSI's system-level flash memory rather than data flash
- Failing or degraded LSI hardware, since the recommended remedy in both cases points toward replacing the LSI gauge or unit
How to troubleshoot JLG Telehandler 99153: first checks
- Confirm the fault is active by checking for the machine system distress indicator and verifying the machine has defaulted to LSI cutout with only override switch operation available
- Check that the machine is not currently in passive mode or LSI calibration mode, since the cutout action is specifically tied to normal operating mode
- Attempt a power cycle of the machine, since the fault is latched until a power cycle occurs; if the fault returns immediately after power up, the LSI module itself is the likely culprit
- Inspect CAN bus wiring and connectors between the LSI and the UGM or ground module for obvious damage, corrosion, or loose connections, since a CAN communication link is how this fault is reported
How the code clears
The fault is latched until a power cycle. If a power cycle does not clear it, the guidance points to replacing the LSI (the load sensing indicator gauge/module), since the problem is an internal checksum error in the unit's own flash memory. No separate reset procedure beyond the power cycle and possible LSI replacement is listed.
Frequently asked questions
What does JLG fault code 99153 mean?
It means the LSI (Load Sensing Indicator) system found a checksum error in its data flash memory and reported it over the CAN bus. The machine treats this as if the load moment cutout limit has been reached and restricts operation.
Can I still operate the telehandler with code 99153 active?
Only in a limited way. The machine defaults to LSI cutout, and operation is only available through the LSI override switch, which runs the machine in a slow creep mode. Normal lifting operation is blocked.
Will turning the machine off and on fix code 99153?
It might. The fault is latched until a power cycle occurs. Cycle power and see if the code clears. If it comes back right away, the LSI module likely needs to be replaced.
Does code 99153 mean I need a new LSI module?
Possibly. Both versions of this fault point toward the LSI hardware itself, since it is an internal flash checksum error. If a power cycle does not resolve it, replacing the LSI gauge/module is the listed remedy.
Why does the machine act like it hit the load moment cutout when this code is active?
Because the LSI can no longer trust its own internal data due to the checksum error, the control system defaults to the safest assumption, which is that the load moment cutout percent parameter has been reached, and it reacts according to how the machine is configured for its market.
Is code 99153 the same whether it comes from the UGM or the ground module?
The underlying cause is the same type of checksum error in the LSI's flash memory. Whether it is reported to the UGM or the ground module, the response is similar: cutout behavior, override-only creep operation, and a latch that requires a power cycle or LSI replacement.