Komatsu Excavator Error Codes When the Machine Is Down
Komatsu excavator error codes come in layers. Which one you read first decides whether you park it, finish the shift or call the dealer.
Table of Contents
Which Komatsu code is on your screen?
This guide covers Komatsu hydraulic excavators in the PC200–PC290 class, -8, -10 and -11 series, noting where Tier 4 Interim and Tier 4 Final machines differ. Codes vary by model and serial range; your Operation & Maintenance Manual decides the final meaning.
Komatsu excavator error codes reach you in three forms: a stop-or-go signal, a specific failure code, and a remote alert from KOMTRAX. Knowing which one you are reading is the first decision.
Stopped right now?
Read the stop rule first, then run the six checks.
Buying or managing a Komatsu?
Read the three layers, then the cost section. Our excavator size guide covers the wider ownership costs.
ℹ️ Safety Note: Park on level ground, lower the work equipment and stop the engine per your manual before inspecting anything. Never stand or work beneath a raised boom, bucket or load. If unsure, call your Komatsu distributor.
Action level, failure code, KOMTRAX alert: three layers
Komatsu reports problems in layers. An action level says whether to stop, a failure code names the fault, and KOMTRAX alerts the owner or dealer remotely.
Action level: the stop-or-go signal
On -11 machines, the monitor shows levels L01 to L04 with a lamp colour and buzzer pattern. Higher is more urgent.
Failure code: the specific fault
Failure codes are letter-and-digit strings, like the CA and DB styles. Each points a technician to one fault; this guide decodes none. Cat’s CID and FMI codes follow a different structure.
KOMTRAX alert: what the office sees
KOMTRAX, Komatsu’s telematics system, can send caution alerts to an owner or dealer. They are separate from the in-cab message.
Your Operation & Maintenance Manual lists the action levels and codes for your serial range.
Stop now or finish the pass? Reading the warning
A red lamp means park the machine. A yellow caution means work can continue, but the cause still needs checking. Verified for -11 machines; earlier series differ.
Red lamp or stop message: park it
A red lamp with a buzzer means stop work; the highest level means stop immediately. Then follow the manual and call your distributor.
🔧 Stop Here: On red, park and shut down per the manual. Do not troubleshoot or keep working; call the distributor service department.
Yellow caution: finish safely, then check
A yellow lamp with no buzzer means work can continue, though functions may be limited. Check it after the shift.
When the code names a safety system
If a message names a safety system, follow your manual’s action table, not the colour alone.
Your manual’s action table decides.
Six checks in order before you call the dealer
Work down this list in order; daily checks and monitor menus are in your Operation & Maintenance Manual.
Checks 1–3: record, read, look
- Record the code, lamp, hour meter, serial number and last task.
- Read the monitor’s DEF level and KDPF soot screens, if fitted.
- Parked per manual, check fuel, coolant, engine oil, hydraulic oil levels.
Checks 4–6: look, battery, key cycle
- Look, don’t probe: air cleaner condition, damaged wiring, loose connectors.
- Check battery condition only as the manual allows; no jump-starting.
- If the signal was not red, key-cycle once; note if it returns.
🔧 Stop Here: Stop after check 6, or sooner if anything looks abnormal or the signal was red. Give the dealer the code, hour meter and serial number.
Should you clear the code?
Ask your dealer before clearing any code.
Ordered safest-first; checked against Komatsu documentation excerpts; not hands-on tested.
Tier 4 machines: regeneration, DEF and warning screens
📋 Compliance Note: The Clean Air Act prohibits tampering with required emission controls, and EPA enforces it on nonroad engines. Such practices exist, are illegal, and cost owners resale value, warranty and liability. Verify requirements with your state agency.
KDPF regeneration burns off the soot the Komatsu diesel particulate filter traps, and it usually runs automatically. The operator can also start a manual stationary regeneration from the monitor panel.
Active regeneration: usually invisible
On Tier 4 Interim (-10) and Final (-11) machines, active regeneration runs on its own. A soot level indicator shows filter loading, per the PC230F-11 brochure.
Manual stationary regeneration: when it is requested
When the monitor requests a stationary regeneration, follow the procedure in your Operation & Maintenance Manual. If requests keep returning or a step is unclear, call the dealer’s service department.
⚠️ Watch Out: Exhaust runs hotter during regeneration. Park clear of brush, fuel and people.
DEF level and low-level messages
Final machines show a DEF level gauge and low-level messages. Check DEF before each shift.
For running-cost impact, see Tier 4 operating costs per hour.
What a stopped Komatsu costs, and what CARE covers
💵 About These Numbers: No repair prices are quoted. CARE terms come from Equipment World’s PC210LC-11 coverage (updated September 2026) and a Komatsu America release for Tier 4 Interim machines. Values vary by region, hours and configuration; confirm current terms with your distributor.
Price a stopped day from hourly machine cost plus idle crew time, then compare it with the dealer’s written quote.
Downtime costs more than the part
Renting a replacement can cost more than waiting out a short stop. See equipment maintenance cost per hour and equipment standby rate billing for the arithmetic.
Komatsu CARE and aftertreatment
| Machine | CARE coverage |
|---|---|
| Tier 4 Interim | Two KDPF exchanges, first 5 years or 9,000 hours |
| PC210LC-11 | Maintenance 3 years or 2,000 hours; two DPF exchanges and DEF tank flushes in the first 5 years |
Sources: Komatsu America release (older); Equipment World PC210LC-11 coverage. Terms differ by era; confirm by serial. If CARE covers the work, don’t pay out of pocket.
Buying used: ask for code and regeneration history
Ask sellers for code and regeneration history, and have the dealer confirm CARE status by serial number.
When to stop and call the dealer
Call the dealer when the signal is red, a code returns after the checks, or soot or DEF warnings persist.
Never work under a raised boom or bucket
Lower the attachment to the ground first; hydraulic pressure is not a support. OSHA 1926.651 bars workers from standing under loads handled by digging equipment.
Lock out before anyone services it
Shut down, remove the key and use the battery disconnect switch where fitted. Your manual sets the lockout steps; a qualified technician does the service.
What to tell the dealer
✅ Do This: Give the dealer’s service department the model, serial number, hour meter reading, action level, failure code as shown, and any earlier soot or DEF warnings. Ask about open recalls.
Frequently asked questions
1. What do Komatsu excavator error codes mean?
Komatsu excavator error codes come in three layers: action level, failure code and KOMTRAX alert. Meanings vary by model and serial range.
2. Can I keep working with a Komatsu error code showing?
With a Komatsu error code on -11 machines, a yellow caution means work can continue, then check it after the shift. Red means stop work and call your distributor.
3. What is the difference between an action level and a failure code?
The Komatsu action level tells the operator whether to stop; the failure code names the specific fault for a technician.
4. Does KOMTRAX show Komatsu error codes?
KOMTRAX can send caution alerts to an owner or dealer, but they are a separate layer from the in-cab message and its codes.
5. What is KDPF regeneration?
KDPF regeneration burns off the soot the filter traps, and it usually runs automatically. A soot level indicator shows filter loading.
6. Can I stop active regeneration?
Active regeneration runs on its own, so follow your Operation & Maintenance Manual rather than interrupting it. If requests keep returning, call the dealer’s service department.
7. Is deleting the DPF or DEF system legal?
No. Tampering with required emission controls is prohibited, EPA enforces it on nonroad engines, and it costs owners resale value, warranty and liability cover.
8. Does Komatsu CARE cover DPF replacement?
Some Komatsu CARE terms include two KDPF exchanges in the first 5 years, but terms differ by era. Confirm yours by serial number.
9. Should I clear a Komatsu code before calling the dealer?
Record the code first, as in check 1, and ask your dealer before clearing any code.
10. When should I call my Komatsu dealer?
Call your Komatsu dealer when the signal is red, a code returns after the checks, or soot or DEF warnings persist.
Before you call: what to have in hand
Write down the code, lamp colour, hour meter and serial number first, run the checks in order, stop when the signal is red, and call your dealer with those details ready. Your Operation & Maintenance Manual remains the final authority for your serial range. Keep the details together with our one-page record sheet.
