Alarm: Homing fail. Y axe doesn't moves

Hi everyone!

When I execute the homing sequence with Arduino IDE ($H), Z axe moves correctly and the limit switch works. Then X axe moves also correctly and the limit switch works fine, but then, the Y axe moves a little (a few millimeters) and then it stop and the IDE Monitor Serie shows “ALARM: Homing fail”. Anyone can help me, please?:sweat_smile:

The Grbl settings are:

Grbl 1.0c [’$’ for help]
[’$H’|’$X’ to unlock]
$0=10 (step pulse, usec)
$1=255 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=3 (dir port invert mask:00000011)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=3 (status report mask:00000011)
$11=0.020 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=0 (hard limits, bool)
$22=1 (homing cycle, bool)
$23=3 (homing dir invert mask:00000011)
$24=25.000 (homing feed, mm/min)
$25=750.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=1.000 (homing pull-off, mm)
$30=1. (rpm max)
$31=0. (rpm min)
$100=40.000 (x, step/mm)
$101=40.000 (y, step/mm)
$102=188.976 (z, step/mm)
$110=8000.000 (x max rate, mm/min)
$111=8000.000 (y max rate, mm/min)
$112=500.000 (z max rate, mm/min)
$120=500.000 (x accel, mm/sec^2)
$121=500.000 (y accel, mm/sec^2)
$122=50.000 (z accel, mm/sec^2)
$130=790.000 (x max travel, mm)
$131=790.000 (y max travel, mm)
$132=100.000 (z max travel, mm)

Did you check your wiring connections for that axis, make sure everything is wired for NO, connected properly to the Arduino etc… it’s easy to flip the NO \ NC connections on those switches.

sounds like bad wiring connection or bad switch. but most likely the wiring

Yes, I have checked all connections and everything is ok. It make me crazy…:sob:

You can use this information to determine what grbl sees when the homing switches are pressed.

Since you are using version 1.0c you will not see LIM label, but you will see PINS: in the status report.

Thanks Larry! When I use the status immediate command (?) the IDE report me:


I am doing something wrong? :disappointed_relieved:

You need to change $10=19

Just I change it, but still does not work…

Interesting. Are you using the X-controller?


Here’s what I get when I do the ? command:


Try $10=255

Just I change it, but still does not work… Now the ? command report me:


Yes, it did. The Pin:010 says that your Y axis homing switch is tripped.

But when I do the $H command still report me “Homing fail”. What can I do now?

You have to determine why your Y axis switch is not working. It is acting like a Normally Closed switch. It could be a wiring error, it could be a defective switch, it could be a defective Arduino.

Try this

Press the Y axis homing switch with your finger and then issue the ? command while you are holding the switch closed.

Post the ? command output here.

While I hold down the Y limit switch, I introduce the ? command and report me the same:


Sorry, now report me:


Most likely is a wiring error.

Can you post a picture of the connector that contains the homing switch wires, that plugs into the gShield?

It just occurred to me that you most likely held down the X axis switch and not the Y axis.

The X axis moves left and right. The Y axis moves forward and back.

So, the Y axis homing switch is on the left at the near end of the Makerslide, not on the gantry.