Komatsu Wheel Loader CA2249 Fault Code: Supply Pump Pressure Very Low Error 2
Also called Rail Press Very Low Error, Rail Pressure Very Low Error, Supply Pump Pressure Very Low Error 2 (Engine Controller System), Supply pump pressure very low error 2, Supply pump pressure very low error 2 (Engine controller system)
Supply Pump Pressure Very Low Error 2 · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CA2249 sets when the engine controller detects a no-pressure feed condition (level 2) in the common rail fuel circuit. The controller limits engine output, keeps the engine running, and turns on the centralized warning lamp and alarm buzzer. Expect hard starting, black exhaust smoke, and reduced power on WA150 through WA500 wheel loaders.
High severity. The engine keeps running but output is limited by the controller. Poor starting, black smoke, and reduced power point to a real fuel delivery problem in the high-pressure common rail system. Running the machine for long periods in this state risks further damage to the supply pump, injectors, or pressure limiter, so it should be diagnosed promptly rather than ignored.
What does Komatsu Wheel Loader error code CA2249 mean?
CA2249 is Komatsu's code for a 'no-pressure feed (level 2)' condition in the common rail fuel system, also described as Rail Pressure Very Low Error or Supply Pump Pressure Very Low Error 2. In plain terms, the common rail pressure sensor is reporting that fuel pressure in the high-pressure rail is well below where it needs to be for proper combustion.
The common rail system relies on the supply pump to build and maintain high fuel pressure, which is then metered to the injectors. If pressure feed drops to this level, the engine controller reacts defensively: it limits engine output and continues operation rather than shutting the engine down outright, while lighting the centralized warning lamp and sounding the alarm buzzer.
On the machine, this shows up as poor starting performance, black exhaust smoke, and lower engine output. These symptoms trace back to insufficient or inconsistent fuel pressure reaching the injectors.
Common causes of CA2249
- Defect in the related fuel system generally
- Use of improper fuel
- Defect in low-pressure circuit parts (the supply side feeding the pump)
- Clogged fuel filter or strainer
- Defective electrical system of the supply pump PCV/EMV (pump control valve/electromagnetic valve)
- Defective common rail pressure sensor
- Defective pressure limiter
- Defective injector, including high-pressure piping in the head
- Defective supply pump
- Fuel leakage to outside the system
How to troubleshoot Komatsu Wheel Loader CA2249: first checks
- Check fuel quality and confirm the correct diesel fuel grade is in use; improper fuel is explicitly listed as a cause
- Inspect the fuel filter and strainer for clogging and replace if dirty or restricted
- Look for visible fuel leaks anywhere along the low-pressure and high-pressure circuits
- Check wiring and connectors to the supply pump PCV/EMV for corrosion, looseness, or damage
- Use the monitoring function to view live common rail pressure (monitor code 36400, RAIL PRESS) and the sensor's voltage output (monitor code 36402, RAIL PRESS) to see if the sensor reading and actual pressure line up
- Inspect the common rail pressure sensor connector and wiring for damage
- Have a technician pressure-test the low-pressure circuit components, pressure limiter, injectors, and supply pump if the above checks don't resolve the fault
How the code clears
No separate clearing step is listed beyond fixing the root cause. Komatsu notes the failure code can be reproduced by starting the engine, so after repairs are made the engine should be started and the monitoring function (36400 and 36402, RAIL PRESS) checked to confirm rail pressure and sensor voltage return to normal before returning the machine to service.
Affected models and serial ranges
CA2249 appears in our records across 11 Komatsu Wheel Loader models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| WA150 | Serial range not listed in source records |
| WA200 | Serial range not listed in source records |
| WA250 | Serial range not listed in source records |
| WA270 | Serial range not listed in source records |
| WA320 | Serial range not listed in source records |
| WA380 | Serial range not listed in source records |
| WA430 | Serial range not listed in source records |
| WA450 | Serial range not listed in source records |
| WA470 | Serial range not listed in source records |
| WA480 | Serial range not listed in source records |
| WA500 | Serial range not listed in source records |
Frequently asked questions
What does Komatsu code CA2249 mean?
It means the engine controller detected a no-pressure feed (level 2) condition in the common rail fuel circuit, essentially very low rail pressure. The controller limits engine output and turns on the centralized warning lamp and alarm buzzer while continuing to run the engine.
Can I keep operating the loader with CA2249 active?
The controller is designed to limit output and keep running rather than shut down, but you'll notice poor starting, black smoke, and reduced power. Because this points to a real fuel delivery fault, it's best to get it diagnosed rather than run it for extended periods.
What is the most common cause of CA2249?
Komatsu lists several possible causes with no single cause ranked first: improper fuel, a clogged fuel filter or strainer, defects in the low-pressure circuit, a faulty supply pump PCV/EMV electrical system, a bad common rail pressure sensor, a defective pressure limiter, injector problems, fuel leakage, or a failing supply pump.
How can I check the fuel pressure sensor reading myself?
Using the machine's monitoring function, you can view live common rail pressure under code 36400 (RAIL PRESS) and the sensor's voltage signal under code 36402 (RAIL PRESS). Comparing these can help identify whether the sensor or the actual pressure supply is the problem.
Why is my exhaust smoking black with this code active?
Black exhaust smoke along with poor starting and reduced engine output are the exact symptoms Komatsu lists for this fault. They result from the engine not getting properly pressurized, metered fuel at the injectors.
Is CA2249 related to a bad fuel filter?
A clogged fuel filter or strainer is one of the causes Komatsu lists for this code, so checking and replacing the filter is a reasonable early step.
Does CA2249 mean the supply pump needs to be replaced?
Not necessarily. A defective supply pump is one of several listed possible causes, but the code can also be triggered by fuel quality issues, a clogged filter, wiring problems at the pump's control valve, a bad pressure sensor, a defective pressure limiter, or injector problems. These should be ruled out first.