Komatsu Excavator D19JKZ Fault Code: Personal Code Relay Abnormality
Also called Personal Code Relay Abnormality (KOMTRAX System In Machine Monitor), Personal Code Relay Abnormally (KOMTRAX System In Machine Monitor, Personal Code Relay Malfunction
Personal Code Relay Abnormality · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
D19JKZ is a Komatsu electrical system fault (Action Level L03) meaning an open circuit or short circuit was detected in the primary (coil) circuit of the personal code relay (R07). It only shows up when the engine lock function is enabled, and affects PC130, PC200, and PC270 excavators.
Medium severity. This code does not stop the machine from running on its own for an open circuit condition, and the machine can self-clear once the fault clears. For a short circuit, the controller shuts off power to the personal code relay and the machine will not return to normal until the starting switch is cycled to OFF. It is not an immediate safety-critical failure, but it can affect the engine lock security feature and should be diagnosed before it leaves you locked out or with an unreliable security function.
What does Komatsu Excavator error code D19JKZ mean?
D19JKZ points to a problem in the primary, or coil-side, wiring of the personal code relay (R07), which is part of the KOMTRAX-linked engine lock system. This relay controls whether the engine lock function allows the machine to operate normally.
When the controller detects an open circuit in this coil circuit, it takes no special action other than logging the code, and the machine will return to normal by itself once the open circuit clears. When it detects a short circuit instead, the controller actively stops output to the personal code relay, and the machine will not return to normal operation until the starting switch is turned OFF, even after the short circuit condition goes away.
The circuit involved runs from the No. 3 fuse in fuse box F01, through the primary coil circuit of personal code relay R07, to the machine monitor. Any fuse, relay, harness, or monitor fault along that path can trigger this code.
What triggers a Komatsu Excavator D19JKZ code?
This code is displayed only when the engine lock function is enabled. For the open circuit condition, it can be reproduced by turning the starting switch to the ON position. The short circuit condition cannot be reproduced on the machine through simple switch cycling.
Common causes of D19JKZ
- Blown No. 3 fuse in fuse box F01 (identified in some listings as the 3rd fuse from the right top)
- Defective personal code relay R07
- Open circuit, short circuit, or ground fault in the wiring harness generally
- Open circuit in the wiring harness caused by wire breakage or a poor connector contact
- Ground fault in the wiring harness
- Short circuit in the wiring harness
- Defective machine monitor (KOMTRAX section)
How to troubleshoot Komatsu Excavator D19JKZ: first checks
- Confirm whether the engine lock function is enabled on the machine, since this code only displays under that condition
- Turn the starting switch to ON and watch for the code to reproduce, which points toward an open circuit condition rather than a short
- Inspect the No. 3 fuse in fuse box F01 for continuity or visible damage and replace if blown
- Check the primary (coil) circuit wiring and connectors between fuse box F01, personal code relay R07, and the machine monitor for breakage, corrosion, loose pins, or chafed insulation
- Test personal code relay R07 for proper coil operation and replace if defective
- Inspect for ground faults or shorts in the harness section covering this circuit
- If wiring and relay check out, inspect the machine monitor (KOMTRAX section) for an internal fault
How the code clears
For an open circuit condition, the machine returns to normal by itself once the cause of the failure is corrected, no separate clearing step is listed. For a short circuit condition, even after the cause is fixed the machine will not return to normal operation until the starting switch is turned to the OFF position, so a full key cycle to OFF is required to clear the fault after repair.
Affected models and serial ranges
D19JKZ appears in our records across 3 Komatsu Excavator models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| PC130 | Serial range not listed in source records |
| PC200 | Serial range not listed in source records |
| PC270 | Serial range not listed in source records |
Frequently asked questions
What does D19JKZ mean on a Komatsu excavator?
It means the controller detected an open circuit or short circuit in the primary coil circuit of the personal code relay (R07), which is tied to the KOMTRAX engine lock function. It is logged as an electrical system fault at Action Level L03.
Will D19JKZ stop my Komatsu excavator from running?
Not directly by itself. For an open circuit, the controller takes no special action and the machine can return to normal on its own. For a short circuit, the controller cuts power to the personal code relay and the machine stays abnormal until the starting switch is turned OFF.
Why does this code only show up sometimes?
This failure code is displayed only when the engine lock function is enabled. If engine lock is not active, this specific code will not appear even if there is an underlying wiring issue.
Which Komatsu models can show D19JKZ?
This code is documented on the PC130, PC200, and PC270 excavator models.
How do I clear D19JKZ after repair?
If the issue was an open circuit, the machine should return to normal on its own once the wiring or component is fixed. If it was a short circuit, you need to turn the starting switch to OFF after the repair, since the fault will not clear on its own even after the short is corrected.
What parts should I check first for D19JKZ?
Start with the No. 3 fuse in fuse box F01, then check personal code relay R07, then inspect the wiring harness between the fuse box, the relay, and the machine monitor for open circuits, shorts, or ground faults. The machine monitor's KOMTRAX section is the last item to check if everything else is good.
Is D19JKZ a safety-critical fault?
It is an electrical system fault tied to the engine lock and monitor circuit rather than to engine, hydraulic, or braking safety systems directly. It should still be diagnosed promptly since it affects machine security and lockout behavior, but it is rated at a moderate action level rather than a critical one.