What the 1105 alarm means
The reported axis failed to reach its target position window within the configured monitoring time — the drive commanded motion but the axis did not follow. This fault appears in a large share of our KUKA KRC2 / KRC4 / KRC5 (KSS) service tickets, and the first round of on-site checks usually finds the source.
Most common causes
- Wrong mechanical or gear-ratio parameters, or $IN_POS_MA / $TIME_POS windows set too tight
- Damaged or leaking balancing system on axis 2/3
- Motor or brake fault — brake not releasing
- Encoder or motor cable connection fault
- Mechanical obstruction or seized gearbox
Step-by-step field fix
- Check for an obstruction or mechanical binding on the reported axis
- Verify the brake releases when drives are on (listen and measure)
- Inspect the motor-encoder cable and connectors
- For axis 2/3, check the balancing cylinder for damage or leakage
- Review $IN_POS_MA[] and $TIME_POS[] after any mechanical change; replace motor or gearbox if the axis still lags
How we diagnose motion alarms on site
KUKA 1105 belongs to the motion & path family. On KUKA 1105 the failing stage is KPP power packs and KSP servo packs (next-generation drive modules on KRC5) on the KRC2 / KRC4 / KRC5 - the gap between command and execution: trajectory planning, joint limits, singularities, following error and mechanical resistance. We start reading KUKA 1105 at the smartPAD message window (KSS message numbers: 1xxx operator, 2xxxx drive) with KPP/KSP module LEDs.
The chain involved in KUKA 1105 runs: program command -> trajectory planner -> joint targets -> servo execution -> actual position feedback -> deviation compare.
If Wrong mechanical or gear-ratio parameters, or $IN_POS_MA / $TIME_POS windows set too tight on KUKA 1105 comes with a feeling of drag, the direction is clear: Following error that stays high on one axis only is usually rising mechanical resistance, not a weak servo. We turn the axis by hand with the brake released to feel smoothness, and listen to the reducer for once-per-revolution knocking - a single tick per turn on an RV reducer usually means internal bearing or cycloid damage. Grease that is black, dry or carries metal powder is the plainest evidence. Left alone, this graduates from a motion alarm to a scrapped reducer.
Field notes on this page cover KUKA 1105 (Positioning Monitoring (Axis N)); written by the Henghuan repair team, updated 2026-10-01.
Real Field Case
Machine: KUKA KR 210 R2700 (KRC4) (2017)
Symptom: A KR 210 raised 1105 (positioning monitoring, axis N) with the positioning deviation out of range.
What we did: We checked the reducer backlash and load on that axis, found wear causing positioning drift, serviced the reducer and recalibrated.
Result: Positioning accuracy recovered and the monitor stopped triggering; about 5 hours.
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Related Motion & Path alarms
1001 — Operator Safety Acknowledgment Required 1002 — Drives-On Not Asserted ($DRIVES_ON) 1004 — File System Error 1010 — Move Enable Missing — E-Stop or Safety Relay Open 1015 — No Program Selected 1020 — Pending Message Not Acknowledged ($CONF_MESS)Frequently asked questions
QWhat does the KUKA 1105 alarm mean?
The reported axis failed to reach its target position window within the configured monitoring time — the drive commanded motion but the axis did not follow. This fault appears in a large share of our KUKA KRC2 / KRC4 / KRC5 (KSS) service tickets, and the first round of on-site checks usually finds the source. KUKA 1105 sits in the motion & path family; on our work orders the highest-frequency trigger for this code is "Wrong mechanical or gear-ratio parameters, or $IN_POS_MA / $TIME_POS windows set too tight".
QCan I clear a KUKA 1105 alarm myself?
Whether KUKA 1105 clears on its own depends on the outcome of "Check for an obstruction or mechanical binding on the reported axis". Finish the flow with "Review $IN_POS_MA[] and $TIME_POS[] after any mechanical change; replace motor or gearbox if the axis still lags" to confirm KUKA 1105 - do not skip it. If that step is clean, the second most frequent cause on KUKA 1105 is "Damaged or leaking balancing system on axis 2/3". Two attempts and still there means stop: KUKA 1105 involves the arm working envelope, and running KUKA 1105 on can turn a repairable fault into a replacement.
QFor motion alarms like KUKA 1105, can you triage remotely first?
The commonest causes we see on KUKA 1105 are "Wrong mechanical or gear-ratio parameters, or $IN_POS_MA / $TIME_POS windows set too tight, Damaged or leaking balancing system on axis 2/3, Motor or brake fault — brake not releasing", so we stock the van against those. For KUKA 1105 specifically, we carry mechanical and configuration items: grease, limit switches, drag-chain segments, encoder cables and the parameter sheets for common reducers. For KUKA 1105, motion alarms can often be narrowed remotely first, so an on-site visit is not always immediate. Before we roll, tell us what KUKA 1105 shows on the smartPAD message window (KSS message numbers: 1xxx operator, 2xxxx drive) with KPP/KSP module LEDs and what the machine was doing - phone or video triage is free.
This page on KUKA 1105 is based on the field experience of the Henghuan Robotics repair team. Alarm explanations are our own summary for troubleshooting reference and may differ across controller and software versions — if unsure, verify against KUKA documentation or reach out to us. Henghuan is an independent service provider with no affiliation or endorsement by KUKA.