Before condemning the controller.Check the condition of the drive motor brushes. Often a dirty armature will cause this code. Also check the condition of the batteries

Hello - did you solve you issue with AL 10? I am having the same alarm and when I lower my handle and power up I first get an AL 04 alarm. Please help

The manual also says the LED should not be flashing. In my experiences I have found AL10 with flashing LED to be a battery or cable issue, or voltage drop at controller B+. If controller doesn't get battery voltage on start up it will drop out.

We have the same problem. We called in a tech from a hyster place, and they gave us a bid of around 2500 to replace the main controller board, handle, and the driver board in the handle. So, we decided to replace the main board, and it still has this problem. It would be good to find out what AL10 even means? Does anyone have the code definitions?

Don't know if you still need the info on this but here is what the manual says, check the drive motor, pump motor, solenoid, brake coil, lift solenoid, lower solenoid. It says to disconnect all of the above, then hook up one and turn on, then another until fault shows up. Check for fields shorted in drive motor.