{"id":353955,"date":"2026-09-13T22:50:24","date_gmt":"2026-09-13T17:20:24","guid":{"rendered":"https:\/\/stitchpartner.com\/?p=353955"},"modified":"2026-09-13T22:50:27","modified_gmt":"2026-09-13T17:20:27","slug":"jack-a4-k4-a5-error-codes-guide","status":"publish","type":"post","link":"https:\/\/stitchpartner.com\/hi\/jack-a4-k4-a5-error-codes-guide\/","title":{"rendered":"JACK A4, K4, A5 Error Codes: Complete Err-01 to Err-23 List"},"content":{"rendered":"

Quick Answer<\/h2>\n

JACK’s A4, K4, A5, ZB-A4F, and ZB-A2S machines are the auto-trimmer, direct-drive lockstitch line, and they share a different control box family from the F4\/F5\/F6 range \u2014 instead of single-letter codes like E1 or E6, they show two-digit “Err-XX” codes on the panel. Across these models we found 19 documented codes: Err-01 through Err-18, plus Err-23. This guide explains what each JACK Err-XX error code means and how to fix it, sourced directly from JACK’s own A4, K4, A5, ZB-A4F, and ZB-A2S operation manuals, plus JACK’s own official maintenance videos. Jump to your code below, or read through for the full picture.<\/p>\n

What Are JACK Err-XX Error Codes?<\/h2>\n

The A4, K4, A5, ZB-A4F, and ZB-A2S are JACK’s auto-trimmer direct-drive lockstitch machines \u2014 the “auto-trimmer” part matters, because these models have an extra thread-trimming solenoid and encoder that the plain F4\/F5\/F6 range doesn’t, which is why their control box needs more fault codes to cover more moving parts. Not every model shows every code \u2014 a given machine will only display the errors relevant to the parts it actually has (a K4 might never show a code that only applies to a feature on the A5, for example).<\/p>\n

These “Err-XX” codes are a completely separate numbering scheme from the E1\u2013EZ codes used on JACK’s F4, F5, and F6 machines \u2014 covered in our separate F4\/F5\/F6 guide<\/a>. If your control panel shows a single letter-plus-digit code like “E4” rather than “Err-04”, you’re on the F-series scheme, not this one.<\/p>\n

JACK Err-XX Error Code Chart: Err-01 to Err-23<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Code<\/th>\nWhat It Means<\/th>\nQuick Fix<\/th>\n<\/tr>\n<\/thead>\n
Err-01<\/td>\nHardware over-current<\/td>\nRestart, check voltage, check for stuck mechanical parts, check motor plug<\/td>\n<\/tr>\n
Err-02<\/td>\nSoftware over-current<\/td>\nRestart; if it repeats, reduce load and check wiring<\/td>\n<\/tr>\n
Err-03<\/td>\nUnder-voltage<\/td>\nCheck supply voltage is within the rated range<\/td>\n<\/tr>\n
Err-04<\/td>\nOver-voltage while the machine is switching off<\/td>\nCheck supply voltage isn’t spiking on shutdown<\/td>\n<\/tr>\n
Err-05<\/td>\nOver-voltage during operation<\/td>\nCheck supply voltage stays within rated range while running<\/td>\n<\/tr>\n
Err-06<\/td>\nShort circuit in the trimmer solenoid<\/td>\nInspect the auto-trimmer solenoid and its wiring<\/td>\n<\/tr>\n
Err-07<\/td>\nMotor current-measuring circuit failure<\/td>\nPower-cycle; contact a technician if it recurs<\/td>\n<\/tr>\n
Err-08<\/td>\nSewing motor blocked (motor stalled)<\/td>\nCheck for a jammed head, thread wrap, or bent needle<\/td>\n<\/tr>\n
Err-09<\/td>\nBrake circuit failure<\/td>\nCheck the brake circuit and control box connections<\/td>\n<\/tr>\n
Err-10<\/td>\nCommunication failure (panel\/HMI to control box)<\/td>\nReseat the panel cable, restart<\/td>\n<\/tr>\n
Err-11<\/td>\nNeedle positioning failure at the machine head<\/td>\nCheck the needle-position sensor and its plug<\/td>\n<\/tr>\n
Err-12<\/td>\nInitial motor electrical angle detection failure<\/td>\nRestart; contact a technician if it repeats<\/td>\n<\/tr>\n
Err-13<\/td>\nMotor Hall sensor failure<\/td>\nCheck the Hall sensor plug and wiring<\/td>\n<\/tr>\n
Err-14<\/td>\nControl board EEPROM read\/write failure<\/td>\nRestart; may need a technician to reset or replace the board<\/td>\n<\/tr>\n
Err-15<\/td>\nMotor over-speed protection triggered<\/td>\nRestart; check the speed parameter setting<\/td>\n<\/tr>\n
Err-16<\/td>\nMotor reverse rotation detected<\/td>\nRestart; check motor wiring phase<\/td>\n<\/tr>\n
Err-17<\/td>\nPanel (HMI) EEPROM read\/write failure<\/td>\nRestart; may need the panel reset by a technician<\/td>\n<\/tr>\n
Err-18<\/td>\nMotor overload<\/td>\nCheck fabric weight, lubrication, and for mechanical resistance<\/td>\n<\/tr>\n
Err-23<\/td>\nMotor blocked with encoder failure<\/td>\nCheck the encoder connection in addition to clearing any jam<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Not every model displays every code above \u2014 the ZB-A4F manual, for example, only documents Err-01, 03, 04, 05, 06, and 07, while the fuller A4 and K4 manuals list all the way to Err-18 and Err-23. Some K4 control boxes also show three unnumbered alerts: a power-off alarm, a trimming-cutter safety-switch alarm, and a sleep-mode (“dormancy”) indicator.<\/p>\n

The Most Common JACK Err-XX Codes Explained<\/h2>\n

Err-01 & Err-02 \u2014 Hardware and Software Over-Current<\/h3>\n

These are the two most-reported Err codes, and both mean the control box detected more current than it expects, either from a hardware sensor (Err-01) or its own internal calculation (Err-02). Power off, wait a minute, and restart. If it repeats on the same fabric, check whether the machine is jammed, under-lubricated, or being asked to sew material that’s too heavy for the setup.<\/p>\n

Err-03, Err-04 & Err-05 \u2014 Under-Voltage and Over-Voltage<\/h3>\n

All three point to the incoming power supply rather than a worn part: Err-03 is under-voltage, Err-04 is over-voltage as the machine switches off, and Err-05 is over-voltage while running. Check the supply voltage against the machine’s rated range before assuming anything mechanical is wrong. A voltage stabilizer is the usual long-term fix where mains supply fluctuates through the day.<\/p>\n

Err-08 & Err-23 \u2014 Motor Blocked \/ Stalled<\/h3>\n

Err-08 means the sewing motor is stalled, and Err-23 is the same fault with an added encoder failure on top. Turn the hand wheel by hand first \u2014 if it’s stiff or won’t move, clear the mechanical jam (thread wrap, bent needle) before checking anything electrical. If the hand wheel turns freely, the fault is more likely in the motor’s drive coupling<\/a> or its Hall sensor.<\/p>\n

Err-11 & Err-13 \u2014 Needle Position and Motor Hall Sensor Faults<\/h3>\n

Err-11 and Err-13 both come from the sensors that track needle and motor position \u2014 Err-11 at the machine head, Err-13 at the motor itself. Check that the sensor plug is fully seated and the wire isn’t frayed or pinched. A worn wheel sensor<\/a> is a common repeat cause of both.<\/p>\n

Err-15 & Err-16 \u2014 Motor Over-Speed and Reverse Rotation<\/h3>\n

Err-15 fires when the motor exceeds its safe speed limit, and Err-16 fires when the motor is detected spinning in reverse. Restart the machine first; if either code returns under normal sewing speed, the speed parameter setting or motor wiring phase needs checking by a technician.<\/p>\n

Err-14 & Err-17 \u2014 EEPROM Read\/Write Failures<\/h3>\n

Err-14 is a fault on the control board’s memory chip, and Err-17 is the same kind of fault on the display panel’s memory chip. Both usually need a technician to reset or reflash the board \u2014 this isn’t something a plug reseat typically fixes.<\/p>\n

Err-06, Err-07, Err-09, Err-10, Err-12, Err-18 \u2014 Other Solenoid, Brake & Communication Faults<\/h3>\n

The remaining codes cover more specific faults: Err-06 is a short circuit in the auto-trimmer solenoid, Err-07 is a motor current-measuring circuit fault, Err-09 is a brake circuit failure, Err-10 is a communication failure between the panel and control box, Err-12 is an initial motor electrical-angle detection fault, and Err-18 is general motor overload. Reseating the relevant plug and restarting clears most of these; if not, they usually point to a control-board-level fault worth a technician visit.<\/p>\n

Preventing Repeat Err-XX Faults<\/h2>\n