FANUC & Robot Alarm Codes: Troubleshooting Guide
How FANUC Alarm Codes Are Organized
FANUC controllers group alarms by a short text prefix that tells you which subsystem raised the fault, plus a group and axis reference formatted as G:i A:j or Group:i Axis:j. SRVO alarms come from the servo system (amplifiers, motors, encoders, DC-link). MOTN alarms come from the motion controller (position, speed, and path errors). SYST alarms come from system-level functions such as memory, configuration, and mastering. INTP alarms come from the program interpreter running the TP program. PRIO and HOST relate to priority tasks and external communication. Each alarm also carries a severity level that determines whether the robot pauses, stops, or requires a controller restart before you can continue. Record the exact prefix, number, and axis reference before you touch anything.
Common FANUC SRVO Servo Alarms
- SRVO-001 – emergency stop condition at the controller panel; check the E-stop circuit, wiring, switches, and safety-chain inputs.
- SRVO-002 – emergency stop condition at the teach pendant; check the pendant E-stop switch, pendant cable, and safety circuit.
- SRVO-021 – servo amplifier ready signal is off; check for concurrent alarms and verify servo, machine-lock, and auxiliary-axis settings.
- SRVO-044 DCHVAL – abnormally high DC-link voltage in the main power supply; check incoming power and the regenerative/drive section.
- SRVO-046 OVC – excessive RMS motor current; caused by overload, friction, external force, brake problems, low voltage, or cable, motor, or amplifier faults.
- SRVO-047 LVAL – abnormally low control voltage, including the amplifier’s +5V supply; check the power supply and amplifier circuitry.
- SRVO-062 BZAL – Pulsecoder absolute-position backup battery is empty or disconnected; replace the battery and confirm the internal connector seated correctly.
- SRVO-067 OHAL2 – Pulsecoder or motor overtemperature thermostat tripped; check load, duty cycle, cooling, motor wiring, and the motor/Pulsecoder assembly.
- SRVO-123 – a controller fan motor is rotating too slowly; inspect or replace the fan motor and cable and confirm ventilation is clear.
- SRVO-214 – a fuse in a six-channel amplifier has blown; find and correct the short circuit or overcurrent before replacing the fuse.
- SRVO-291 – IPM overtemperature in the servo amplifier; check for clogged vents, fan operation, cabinet temperature, load, and the power stage.
- SRVO-295 – amplifier communication error involving the main board; check amplifier-to-controller cabling, power supplies, and communication circuitry.
Step-by-step guides: FANUC SRVO-062 BZAL alarm · FANUC SRVO-046 OVC alarm · FANUC SRVO-068 DTERR alarm · Yaskawa V1000 alarm and fault codes · FANUC SRVO-037 IMSTP input · FANUC INTP-105 run request failed · FANUC SRVO-230/231 chain abnormal · FANUC SRVO-402 DCS limit · FANUC SRVO-280 SVOFF input.
Motion, System and Program Alarms
Beyond SRVO, three other prefixes account for most non-servo faults.
- MOTN alarms flag motion-control problems such as a commanded position outside the robot’s reach, a joint or axis limit violation, or a path that cannot be executed as programmed.
- SYST alarms flag controller-level problems, including memory or configuration errors and mastering or calibration data that does not match the robot.
- INTP alarms flag TP program problems raised by the interpreter, such as a program logic error, a missing or undefined position register, or an instruction that cannot execute in the current mode.
As with SRVO alarms, check the alarm history for a concurrent SRVO or system alarm before assuming the MOTN, SYST, or INTP message is the root cause; interpreter and motion faults are frequently triggered by an underlying servo or I/O condition.
Alarm Codes on Yaskawa, ABB and KUKA Controllers
Yaskawa Motoman DX and YRC controllers (YRC1000 and earlier) use numeric alarm codes grouped by category: safety, communication, servo, encoder, amplifier, overload, cooling and position faults. The exact meaning depends on the controller generation, so match the code to the manual for that controller family before acting on it.
ABB IRC5 and OmniCore controllers log events with numeric codes classified as positioning, communication, motion, drive, safety or maintenance messages. The category tells you which checks apply, and the event log records the sequence that led to the stop.
KUKA KRC4 controllers report numbered messages per axis and drive. Record the message number together with the axis it names, and read the message history before acknowledging, since the first message in a sequence is usually the cause.
Whatever the brand, the rule is the same as on FANUC: capture the full code, the axis and the history before you reset.
Reading the Alarm History Before You Reset
Before you clear a FANUC alarm, open the alarm history and read backward from the fault that stopped the robot. A single event can trigger several alarms at once, and the earliest one in the sequence is usually the actual cause rather than the alarm displayed on top. FANUC controllers also provide alarm descriptions and troubleshooting help through the alarm and diagnostic screens; use them to confirm the alarm’s stated cause before assuming a part has failed.
Record the complete alarm text exactly as shown, including the SRVO/MOTN/SYST/INTP prefix, the number, and the group and axis reference (G:i A:j). Also note what the robot was doing at the moment of the fault, whether the alarm repeats on a specific axis or motion type, and any other alarms logged within the same cycle. This record is what a technician needs to diagnose the fault remotely or over the phone.
How Robotics Integration Handles Alarm Troubleshooting
Robotics Integration troubleshoots FANUC SRVO, MOTN, SYST, and INTP alarms along with Yaskawa, ABB, and KUKA fault codes by working through the alarm history, cable and connector continuity, incoming power and phase balance, load and duty cycle, and brake operation before condemning a component. Robot connection cables and internal robot power cables are checked for continuity whenever a servo or motor fault is suspected, and payload is checked against rated capacity when overcurrent, overload, or thermal alarms appear.
When a component is at fault, our repair work covers amplifier and drive boards, servo motors, and related power electronics at the component level: DC-link, fuses, IGBT/IPM devices, gate-drive circuits, control power supplies, communication circuits, cooling, and protection circuitry, matched to the exact part number and schematic for that amplifier. Repaired units are functionally tested in a compatible controller and robot system before they are returned to service.
What To Send Us and How To Reach Us
To get a fast, accurate read on an alarm, call 1-602-449-1556 and have this information ready: the controller model (R-30iA, R-30iB, R-30iB Plus, YRC1000, IRC5, OmniCore, or KRC4), the exact alarm text including prefix and number, the group and axis reference, the alarm history around the fault, and which axis or motion is affected. If a fan, amplifier, motor, or drive is suspected, note the part number and any visible damage. This information lets a technician narrow the cause before parts are pulled or shipped.
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