Alarm guide · Fanuc · Updated October 2026
Fanuc SV0368 alarm: Serial Data Error (INT)
Fanuc SV0368 means the communication data from the built-in Pulsecoder could not be received correctly. It usually comes from the feedback cable or connector, often damaged by coolant or chips, or from a faulty Pulsecoder. If a good cable does not clear it, the motor needs repair.
By Suresh Sankaran, founder of Star Automations, servo motor repair since 1998.
What the alarm means
Fanuc SV0368 means the communication data from the built-in Pulsecoder could not be received correctly. It usually comes from the feedback cable or connector, often damaged by coolant or chips, or from a faulty Pulsecoder. If a good cable does not clear it, the motor needs repair.
A related pulsecoder alarm, SV0366 Pulse Miss (INT), points to the same feedback path and gets the same first checks.
Safe first checks
General guidance only. Follow the drive manual and your site's electrical safety rules. Power off, and let the DC bus discharge, before touching connectors.
- Power off the machine before touching connectors.
- Check the feedback connector at the motor for coolant, chips and corrosion.
- Inspect the feedback cable along its run, especially in cable chains.
- Swap the feedback cable with a known-good one, or swap motors between axes if possible, to see whether the alarm follows the motor.
When to send it for repair
Send the motor when the alarm follows it. The Pulsecoder is tested, repaired or replaced, and aligned to the motor before the run test. Send the amplifier too if the alarm stays on that axis with a good motor and cable.
See Fanuc servo motor repair, encoder repair and servo drive repair.
Questions
Can I clear the SV0368 alarm and keep running?
A reset may clear it for a while, but a feedback alarm usually comes back until the cable, connector or encoder is fixed. Running with an intermittent feedback fault can stop the axis without warning, so find the cause first.
Is it the motor, the cable or the drive?
Swap with a known-good cable first, then swap the motor to another axis if you can. If the alarm follows the motor, send the motor. If it stays on the axis with a good motor and cable, send the drive. We test both when you are not sure.
How long does repair take?
Emergency repair is done the same day where the fault and parts allow, urgent in 3 working days and standard in 7 working days, counted from when the unit reaches our bench and the quote is approved. Every unit returns with a printed test report.
Can I get an exchange unit?
If we hold a matching unit, Servo Swap ships a tested exchange unit while yours is repaired. Mark "line down" on the request form and add the part number.
Brand names identify the units we repair. Star Automations is an independent multi-brand repair company and is not an OEM service centre.