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known-issue

LUBA 3 AWD: "Front bumper is experiencing repeated triggering" (error 1207)

Models covered
LUBA 3 AWD
Affects
Robot body — not the app
First reported
13 August 2026
Last updated
30 September 2026
Status
Open

What to do next

  1. Power the mower off, take the front bumper off and clear the debris from inside it and its seams - owners found mostly fine, packed grass clippings, and low-pressure compressed air or a soft brush got them out. Check the connectors for dirt or moisture while it is off.

    Applies when: the mower stops with error 1207 (front bumper repeated triggering) while nothing is touching it, especially after mowing wet or long grass.

    Worked if: the bumper moves freely again and the mower runs a full task without stopping.

    Didn't work? Next: step 2 — Refit the bumper with all four linkage connectors snapped fully...

    Method: one LUBA 3 AWD owner whose clean held for 12+ hours of mowing, two for whom it did not hold, and the same step from an account answering as support

  2. Refit the bumper with all four linkage connectors snapped fully into their clips, push it into its slot until you hear it click, and only then tighten the screws. Then power off for about 30 seconds, restart, and test on a flat, open patch of lawn.

    Applies when: cleaning alone did not stop the error, or the bumper has been off recently.

    Worked if: a bumper that was sitting slightly out of place stops reporting false hits.

    Didn't work? Next: step 3 — Upload a log from the app and contact support with photos of the...

    Method: the steps an account answering as support gave in one thread, not a company-named statement

  3. Upload a log from the app and contact support with photos of the bumper's connector and port. Ask whether the error still appears with the bumper removed - if it does, say so plainly, because a part that is not fitted cannot be causing it.

    Applies when: the error keeps coming back after cleaning and a careful refit.

    Worked if: the case moves to a warranty bumper, or to the mower's internal wiring, instead of another round of reinstalling.

    Didn't work? Next: step 4 — Tell us what fixed it - cleaning, a refit, a new bumper, or a...

    Stop and get help if: the error fires with the bumper off the machine - stop swapping parts and ask for the internal collision-sensor wiring to be checked under warranty.

    Method: one owner's five-week support case, where support finally named a possible internal wiring fault

  4. Tell us what fixed it - cleaning, a refit, a new bumper, or a repair inside the mower - and which firmware version you are on.

    Applies when: any step above settled it, or none did.

    Worked if: the next owner can see which cause is most common, and whether a firmware version is involved.

    Method: this page's own closing request

Did this work, or not? Tell us what happened — a report from someone who hit it is what turns one dealer's method into a documented fix.

Before you start: if your LUBA 3 AWD keeps stopping with error 1207 — "Front bumper is experiencing repeated triggering" — while nothing is touching it, clean out the inside of the bumper and refit it until it clicks before you assume the mower or the firmware is at fault. That is where every owner below started, and it fixed it for some. If the error still appears with the bumper taken off, the fault is inside the mower.

The symptom

The mower stops mid-task and reports that the front bumper is being triggered over and over. It happens in open grass with nothing nearby, and some owners see it within minutes of restarting. One owner said the mower ran for five minutes, stopped, and did it twice more before a full power-off, with the safety key removed for a few minutes, let it finish a six-hour task2. A brand-new LUBA 3 H 5000 in the same thread did not make it to its second day2.

What owners found

Packed grass clippings inside the bumper. The bumper's outer cover slides over an inner bracket, and the small gaps between them let debris in. One owner took the bumper off, used low-pressure compressed air, and "was surprised by how much was there. Mostly very fine grass clippings." The mower then ran about 12 hours without the error3. The same owner, in their own earlier thread, had already run seven hours clean after the first time they blew the bumper out2. Their guess — theirs, not Mammotion's — is that the clippings shortened how far the bumper had to move before it registered a hit3. A third LUBA 3 owner opened up and cleaned their bumper and still saw the error loop1.

Cleaning did not always hold. For another owner, on firmware 2.3.30.26, cleaning worked "for a day or a month" each time. They sent photos to Mammotion and received a replacement bumper under warranty within a few business days1.

A bumper that is not fully home. In a thread started after firmware 2.3.30.39, an account answering as Mammotion support gave these steps: power off for 30 seconds and restart; take the bumper off and clean the seams; refit it with "all four linkage connectors" snapped into their clips; push it into the slot until it clicks before tightening the screws; then test on flat, open ground4. That account is not company-named, so treat these as support's working steps rather than an official statement.

When the bumper is not the cause. One owner removed the bumper entirely at support's request and told the mower to return to its station: "Bumper completely off the machine, commanded a return to the station, and it threw the same 1207."3 After five weeks and five reinstalls, support told them there may be an internal wiring fault in the front collision sensor. In another case — an owner on 2.3.30.39 who does not name their model — the bumper moved freely and beeped when pressed by hand, yet the error still stopped the mower right after the update4. That owner reads it as a software false alarm. This site has not confirmed that.

Is it a firmware problem?

Not shown. Owners have reported 1207 on firmware 2.3.30.26, after an August 2026 update, and after 2.3.30.39. At least two owners had it before the 2.3.30.39 update3. A LUBA 1 owner and a LUBA 2 AWD X owner in the same threads describe similar bumper faults traced to the connection: a dealer who suspects moisture in the contacts in one case, a plug that needed reseating in the other23. So far this looks like several physical causes producing the same error code, not one confirmed defect.

If error 1207 keeps stopping your LUBA 3 AWD: clean out the inside of the bumper, refit it until it clicks, and test in the open. If it keeps coming back, upload a log and send support photos of the connector. If it appears with the bumper removed, say so, and ask for the internal wiring to be checked under warranty. Tell us what fixed it and which firmware you are on.
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Sources