Start here — before replacing any parts
Err-13 points to the motor Hall signal in the reference controller. Check its plug and cable before condemning the motor.
Confirm your JACK A4B uses the A4B-A-C control-box edition; fault tables are not necessarily identical across controllers.
Manual scope: Control box Hall connector; do not jump to replacement
Do these checks in order
Follow the steps below and keep a record of what changes after each one. Stop when an actual cause is confirmed.
Unplug the machine and identify the motor sensor/Hall connector for the specific A4B-A-C control box.
Check the disconnected harness for a partly backed-out plug, crushed cable or bent external pin. Do not probe live Hall pins or interchange motor connectors.
Reseat only the correctly keyed connector; route the wire clear of moving machine parts, then close the guards.
Restart and run a low-speed test. If the code returns, record whether the motor attempts to turn or never starts.
If the problem is gone
Err-13 clears after correcting a loose sensor connection and normal motor motion returns: no motor replacement is indicated.
If the problem is still there
Code remains: service should test sensor supply/signal and harness against the control unit’s approved specifications before ordering a Hall sensor or motor.
Which cause matches your result?
Use these more specific checks only when the earlier steps point to that possibility.
01The motor Hall connector is loose
Turn off and unplug the machine, then inspect the correct motor sensor plug.
Reconnect securely and restart according to the manual.
02The fault returns
A damaged sensor or cable is possible but not proven by the code alone.
Have the Hall sensor and harness tested before replacing a component.
How can I tell it is actually fixed?
Check repeatable low-speed operation and ensure the fault stays absent after a complete restart.
Before buying a replacement part
Hall sensors, motor connector styles and controller boards are not universal across JACK models.
Where this guidance comes from
Primary reference: View the manufacturer or manual reference ↗
Applicability: Control box Hall connector; do not jump to replacement. Source evidence: Manufacturer manual confirmed; user search demand unquantified.
The instructions are original English troubleshooting explanations derived from the listed technical facts; they are not a verbatim service manual. Do not apply them to an unverified revision.