Komatsu Excavator DA2RMC Fault Code: CAN Discon (Pump Con Detected)
Also called CAN Communication Disabled, CAN Discon (Pump Controller Detected), CAN Disconnection (Pump Controller Detected), CAN Disconnection (Pump Controller Detected) (Pump Controller System), CAN Disonnection (Pump Controller Detected), Pump Communication Abnormality, Pump Communication Error
CAN Discon (Pump Con Detected) · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
DA2RMC (user code E0E) means the pump controller detected a CAN communication error with the machine monitor or engine controller. Engine output gets locked to P mode with limited pump absorption torque until the fault clears itself. Affects PC130, PC200, and PC270 excavators.
High severity. The machine keeps running on last-known CAN data and the engine controller locks output to P mode with reduced pump absorption torque. Under heavy load this can stall the engine, and other CAN-dependent functions may behave unpredictably. Not an immediate shutdown, but not safe to ignore either.
What does Komatsu Excavator error code DA2RMC mean?
>A row of overlapping OEM records refers to DA2RMC, with the shared theme that the pump controller has lost or detected a fault in CAN communication with the machine monitor and/or engine controller. Some records describe this as the CAN communication line or ACC line from the starting switch being abnormal.
Because the failure code itself gets transmitted to the machine monitor over the CAN line, its very appearance proves that the CAN link between pump controller and machine monitor is functioning at a basic level. That rules out a hard short, ground fault, or hot short directly in that specific communication line, according to the notes tied to this code.
When the fault sets, the machine monitor keeps controlling the machine using the last good CAN data it had before the error appeared, and locks engine output to P mode, limiting pump absorption torque to a fixed value. If the underlying cause goes away, the system is designed to reset itself automatically without intervention.
Common causes of DA2RMC
- Defective circuit breaker No. 7
- Blown or defective fuse (referenced across records as fuse F01-18, F01-19, or F01-20)
- Defective engine controller, including possible internal short circuit
- Improper power supply to the engine controller
- Defective CAN terminating resistor, either an internal open circuit or internal short circuit
- Open or short circuit in the wiring harness, including wire breakage or a defective connector contact
- Defective diode D02, either internal open circuit or internal short circuit
- No ACC signal from the starting switch, so CAN communication start is not sensed
- Ground fault in the wiring harness (short circuit with the GND circuit)
- Hot short in the wiring harness (short circuit with the 24V circuit)
- Defective engine controller (general failure, separate from internal short)
- Defective pump controller
How to troubleshoot Komatsu Excavator DA2RMC: first checks
- >Turn the starting switch to the ON position, since this is the listed method for reproducing the failure code, and note whether DA2RMC reappears.
- Check whether the air conditioner can still be turned on and off and its air flow adjusted from the air conditioner screen. Since the air conditioner also runs on CAN communication, if it still works normally while DA2RMC is displayed, that helps isolate which section of the CAN network is affected.
- Check the machine monitor for any other active failure codes at the same time. If DAFRMC is also displayed, the engine controller is the likely cause. If DY20KA, DY20MA, or DW43KA is also displayed, the pump controller is the likely cause.
- Inspect circuit breaker No. 7 and the relevant fuse in fuse block F01 (positions referenced as 18, 19, or 20 depending on the record) for continuity.
- Visually inspect the wiring harness and connectors in the CAN circuit for corrosion, loose pins, chafing, or broken wires, and check for any wear that could cause a short to ground or to the 24V circuit.
- Check the CAN terminating resistor for an internal open or short circuit.
- Remember that active CAN communication is a pulse voltage signal, so it cannot be measured with a standard multimeter. Do not rely on static voltage readings at the pump controller connector, since the T-adapter for that connector is a socket-type box and operating voltage cannot be measured there directly.
How the code clears
No separate reset procedure is listed for this code beyond letting the system recover. The machine monitor is designed to return the machine to normal operation automatically once the underlying cause of the CAN communication error disappears. If the fault keeps returning after turning the starting switch to ON, the underlying electrical cause listed above needs to be found and repaired rather than just cleared.
Affected models and serial ranges
DA2RMC 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 DA2RMC mean on a Komatsu excavator?
It means the pump controller detected a communication error in the CAN circuit linking it to the machine monitor and/or the engine controller. It shows on the monitor with the user code E0E.
Can I keep operating the excavator with DA2RMC displayed?
The machine will keep running using the last good CAN data and the engine controller locks output to P mode with limited pump absorption torque. Output is noticeably lower, and if actuator or work load increases, the engine may stall. It is best treated as a stop-and-diagnose-soon condition rather than something to run through a full shift.
Does DA2RMC mean the CAN wiring itself has a short circuit?
Not necessarily in the exact line that carries the failure code to the monitor. Because DA2RMC is transmitted to the machine monitor over that same CAN line, its appearance actually proves that particular link is functioning enough to communicate, ruling out a short circuit, ground fault, or hot short in that specific line.
Why does the air conditioner still work when this code is active?
The air conditioner runs on the same CAN communication network, so checking whether it can still be turned on and off and its air flow adjusted is a diagnostic step. Komatsu notes the air conditioner can still be operated even while DA2RMC is displayed, which helps narrow down which CAN section has the fault.
Does DA2RMC always mean the pump controller is bad?
No. The listed causes range from a blown fuse or defective circuit breaker to a bad CAN terminating resistor, harness damage, or engine controller problems. A defective pump controller is only one of several possible causes, and checking for related codes like DAFRMC, DY20KA, DY20MA, or DW43KA can help point toward engine controller versus pump controller as the likely source.
Will DA2RMC clear itself?
Yes, if the underlying cause goes away, the system is designed to reset itself automatically. No manual reset procedure is listed for this code.
What is the ACC signal mentioned with this code?
ACC refers to the accessory signal from the starting switch. Each controller uses that ACC signal to recognize the start of CAN communication, and some records list no ACC signal being sensed as a possible cause of this fault.