SINAMICS G120 & S120 Fault Codes: Meanings & Checks

Quick answer

A SINAMICS drive shows a fault as F plus five digits (for example F30002) and an alarm as A plus five digits (for example A07910). A fault makes the drive react – OFF1 ramps the motor down, OFF2 switches the pulses off so it coasts, OFF3 is a quick stop – and stays until it is acknowledged. An alarm is a warning that clears itself once its cause is gone. Find the code below, fix the cause, then acknowledge the fault.

Jump to a code:

Safety first: lock out and tag out the drive and the machine before you open a drive or touch the wiring, and follow Siemens' safety instructions in the hardware manual for your power unit. The DC link capacitors stay charged after power is removed: Siemens' manuals for the PM240-2 Power Module and the S120 booksize power units say to wait 5 minutes (other power units give their time on the warning label); then a qualified person, with a properly rated meter checked on a known source before and after, confirms that there is no voltage between any of the power terminals and between them and ground – a dark display doesn't mean it's safe. Never bypass Safe Torque Off or any other safety circuit, and never switch off a fault to keep a machine running. Only qualified personnel should work on drives, and any measurement on energized equipment follows your site's live-work and arc-flash rules.

Reading and acknowledging a SINAMICS fault

Note the code and its value. r0945 lists the fault codes – the current fault case and the last seven acknowledged ones – and r0949 holds each fault's value, which many codes use to say which phase or which bit tripped. r2122 lists the alarm codes.
Look it up in the table below or in the List Manual, and fix the cause first – a fault whose cause is still there comes straight back.
Acknowledge it the way the table's “Ack” says: IMMEDIATELY – set p3981 from 0 to 1, give a 0-to-1 edge on the input set in p2103, send control word bit STW1.7 from the PLC, or power-cycle; POWER ON – switch the drive off and on; PULSE INHIBIT – only once the pulses are off. Safe Torque Off has to be deselected before a Safety Integrated fault can be acknowledged.
Watch the restart. If the same code returns, go back through the checks before acknowledging again.

One page for G120 and S120

The G120 and S120 List Manuals use the same SINAMICS numbering: every shared code in the table has the same number in both, and the same name apart from a few wording differences noted in the table (for example F08501 and A08526, which the S120 manual calls PN/COMM BOARD messages). The S120 adds its own ranges for the infeed (Line Modules, F06xxx) and for encoders on DRIVE-CLiQ (F31xxx); rows marked “S120 only” or “G120 only” are in one of the two manuals only. On an S120 the same power unit code (F30xxx) can come from a Motor Module or from the Line Module, so check which drive object reports it. A message's reaction and type can be changed with parameters, so a drive that was set up differently may react differently from the defaults shown here.

Common SINAMICS G120 / S120 fault codes

This list covers the codes technicians run into most often, not every code – the List Manuals have hundreds more. The manuals have the complete list, the fault values and the full remedies.

Code	What it means	Likely causes	First checks
F07801Drive: Motor overcurrentAck: IMMEDIATELY OFF2	Motor current went above the motor current limit the drive is allowed to deliver.	Ramp-up too short or too much load (U/f control) A short or a ground fault in the motor or the motor cable Current limit or current controller set wrong, or switching onto a motor that is still turning	With power locked out, check the motor and cable for a short or a ground fault Lengthen the ramp-up time (p1120) or reduce the load Check the current limit (p0640), the motor nameplate data and star / delta wiring For a coasting motor, use the flying restart function (p1200)
F07802Drive: Infeed or power unit not readyAck: IMMEDIATELY OFF2	After the switch-on command, the infeed or the power unit did not report ready in time.	No DC link voltage (supply off, or on an S120 the Line Module not switched on / enabled) Supply voltage setting p0210 wrong A defective infeed or power unit, or a monitoring time too short	Read r0026 (DC link voltage) on the drive first; checking the incoming supply is live work for a qualified electrician On an S120, check the Line Module, its enable and the DC link busbars Check p0210 and the power unit monitoring time p0857
F07807Drive: Short-circuit/ground fault detectedAck: IMMEDIATELY OFF2	The drive found a phase-to-phase short or a ground fault at its motor terminals.	A shorted or grounded motor cable or winding Line and motor cables swapped at the drive Switching onto a motor that is still turning or still magnetized	Read the fault value r0949: 1 to 3 name the shorted phase pair (UV, UW, VW), 4 a ground fault With power locked out, a qualified person insulation-checks the motor and cable Make sure line and motor wiring are not swapped
F07011 / A07910Drive: Motor overtemperatureAck: IMMEDIATELY OFF2	The motor's temperature sensor or the drive's motor thermal model is over the limit; A07910 is the warning stage before it.	Motor overloaded Hot surroundings or blocked motor cooling A broken wire or a missing PTC / KTY / PT1000 sensor	Reduce the load; check the motor fan and the air around the motor Check the sensor wiring and the sensor type set in p0601 Thresholds and the drive's reaction: p0604, p0605 and p0610
F07900Drive: Motor blockedAck: IMMEDIATELY OFF2	The motor ran at its torque limit below a set speed for longer than the set time.	A jammed or binding machine Torque or current limits too low An oscillating speed loop or, on an S120 with an encoder, a wrong encoder setting	With power locked out, check that the motor and the machine turn freely Check the torque limits (r1538, r1539) and the blocked thresholds p2175 / p2177 On an S120 axis the text reads “Motor blocked/speed controller at its limit”: check the encoder too
F07901Drive: Motor overspeedAck: IMMEDIATELY OFF2	Motor speed went past the maximum speed plus the set margin, in either direction.	Maximum speed p1082 or the overspeed margin p2162 set too close to the running speed Speed overshooting past the limit	Check the active limits (r1084, r1087) against p1082 and p2162 The manual also suggests the speed limiting controller's precontrol (p1401.7 = 1)
F07902Drive: Motor stalledAck: IMMEDIATELY OFF2	The drive's motor model decided the motor stalled for longer than the set time (p2178).	Ramp times too short or too much load Motor data identification not done, or motor data wrong A lost line phase or a disconnected motor cable	Run the motor data identification if it was never done (p1900) Lengthen the ramp times (p1120, p1121) or reduce the load Check the line phases and the motor cable connections
F07860 / F07861 / F07862External fault 1Ack: IMMEDIATELY OFF2	A signal wired to the external fault input dropped (a 1 to 0 change); F07861 and F07862 are inputs 2 and 3.	A device wired to that input (overtemperature switch, interlock) opened A loose wire on that input The PLC dropped the signal on purpose	Find what is wired to the input set in p2106 (p2107, p2108 for faults 2 and 3) Fix the cause, then acknowledge the fault
F07320Drive: Automatic restart interruptedAck: IMMEDIATELY OFF2	Automatic restart used up its restart attempts without the original fault clearing.	The fault that started the restarts is still present Restart attempts (p1211) or monitoring time (p1213) set too low	Automatic restart can start the motor without warning: remove the ON command before working on the machine Look in the fault buffer (r0945) for the original fault and fix that Only then check p1211, p1212 and p1213; never raise the attempts to ride over a fault
F07806Drive: Regenerative power limit exceeded (F3E)Ack: IMMEDIATELY OFF2G120 only	A PM250 or PM260 Power Module fed back more than its rated regenerative power for over 10 s.	Ramp-down too short for the load An overhauling load (lowering, unwinding)	Lengthen the ramp-down time or reduce the driving load Check the regenerative power limit p1531 (vector control)
F07412Drive: Commutation angle incorrect (motor model)Ack: IMMEDIATELY ENCODERS120 only	The drive found that the encoder's rotor position does not match its motor model.	Motor phases swapped Encoder moved, damaged or not adjusted to the magnets Wrong commutation offset (p0431) or motor data	With power locked out, check the motor phase order If the encoder was removed or replaced, it needs adjusting again Check p0431 and the motor data
F30001Power unit: OvercurrentAck: IMMEDIATELY OFF2	The power unit's own current monitoring tripped; the fault value r0949 shows which phase.	A short or ground fault in the motor or the power cables Ramp-up too short or a motor much larger than the power unit Control set up wrong, power cables too long, or a defective power unit	With power locked out, check the motor and cables for a short or a ground fault Check the motor data, star / delta wiring and the ramp-up time Check the cable length against the hardware manual; the List Manual also lists replacing the power unit
F30002Power unit: DC link voltage overvoltageAck: IMMEDIATELY OFF2	The DC link voltage went above the power unit's limit.	The motor feeding energy back while it slows a heavy load Ramp-down too short, or the DC link voltage controller switched off Supply voltage too high, or a lost line phase	Lengthen the ramp-down time (p1121) and check the Vdc controller (p1240 / p1280) Read r0026 (DC link voltage) and check p0210; checking the supply itself is live work for a qualified electrician For loads that keep regenerating, the S120 manual names a braking resistor or an Active Line Module
F30003Power unit: DC link voltage undervoltageAck: IMMEDIATELY OFF2	The DC link voltage dropped below the power unit's minimum.	Supply interruption or low line voltage A lost line phase On an S120: the infeed (Line Module) failed or was switched off	Read r0026 (DC link voltage) first; checking the supply while running is live work for a qualified electrician, or use a power-quality recorder Check fuses and all three phases On an S120, check the infeed and its own fault messages
F30004Power unit: Overtemperature heat sink AC inverterAck: IMMEDIATELY OFF2	The power unit's heat sink got too hot; A05000 is the warning stage.	A stopped fan or poor cooling Ambient temperature too high Overload, or a pulse frequency set above the rated one	Check that the fan runs and the airflow is clear Measure the temperature around the drive Check the motor load and the pulse frequency p1800
F30005Power unit: Overload I2tAck: IMMEDIATELY OFF2	The power unit carried more than its rated current for too long (r0036 reached 100 %).	Continuous load too high for the power unit A duty cycle the unit is not rated for	Reduce the continuous load or adapt the duty cycle Compare the motor and power unit rated currents Check the current limit p0640
F30011Power unit: Line phase failure in main circuitAck: IMMEDIATELY OFF2	DC link ripple got too high, which usually means a missing or unbalanced line phase.	A blown fuse or a lost line phase Badly unbalanced line voltages A resonance between the supply and the drive, or a lost motor phase	Check the main circuit fuses with power locked out; checking the three phases live is for a qualified electrician or a power-quality recorder Look for single-phase loads distorting the supply Check the motor cables
F30015Power unit: Phase failure motor cableAck: IMMEDIATELY OFF2	The drive found a missing phase on the motor cable.	An open conductor or a loose terminal between drive and motor A stalled U/f drive or an unstable speed loop can show the same	Check the motor cable and terminals end to end Lengthen the ramp times if the drive stalls in U/f control Chassis power units have no phase failure monitoring
F30021Power unit: Ground faultAck: IMMEDIATELY OFF2	The power unit found current flowing to ground.	Damaged insulation on the power cables A motor winding with a fault to ground A short at the braking resistor, the brake wiring or a defective current sensor	With power locked out, a qualified person insulation-checks the motor and cables Check the braking resistor and the brake cable Thresholds: p0287
F30024Power unit: Overtemperature thermal modelAck: IMMEDIATELY OFF2	The drive's thermal model of its power semiconductors went over the limit.	A duty cycle the unit is not rated for, or overload A fan problem or high ambient temperature Pulse frequency too high, or heavy DC braking	Adapt the duty cycle and check the motor load Check the fan and the ambient temperature Check the pulse frequency; reduce the DC braking current (p1232) if used
F30027Power unit: Precharging DC link time monitoringAck: IMMEDIATELY OFF2	The DC link did not charge up within the expected time at switch-on.	No line voltage, or the line contactor / switch not closed Line voltage too low or p0210 wrong Precharge resistors hot from too many power-ups, or a DC link short	Read r0026 first; checking the voltage at the input terminals is live work for a qualified electrician Check p0210 Let the precharge resistors cool down; check the allowed switch-on rate in the hardware manual
F30036Power unit: Internal overtemperatureAck: IMMEDIATELY OFF2	The temperature inside the drive went over the limit.	A fan problem Overload Ambient temperature too high	Check the fan and the airflow Measure the temperature around the drive It can be acknowledged only once the inside has cooled 5 K below the limit
F30059Power unit: Internal fan faultyAck: IMMEDIATELY OFF2	The power unit's internal fan has failed.	A worn or blocked fan	With power locked out, check the internal fan and replace it if needed
F01910Fieldbus interface setpoint timeoutAck: IMMEDIATELY OFF3	The drive stopped receiving setpoints over the fieldbus (PROFIBUS, PROFINET or USS).	A cable, connector or switch problem The PLC switched off or set to STOP Bus monitoring time too short	Check the bus cabling and put the PLC in RUN Check the monitoring time p2040 The S120 text reads “Fieldbus: setpoint timeout”
F08501PROFINET: Setpoint timeoutAck: IMMEDIATELY OFF3	Setpoints over PROFINET stopped arriving; the S120 List Manual names it “PN/COMM BOARD: Setpoint timeout” (a COMM BOARD, CBE20).	A cable or switch problem The controller switched off or set to STOP Update time in the bus configuration too short, or a defective COMM BOARD on an S120	Restore the connection and put the controller in RUN If it repeats, check the update time in the bus configuration
A08526PROFINET: No cyclic connectionAlarm	No cyclic connection to a PROFINET controller (an alarm; it clears itself). The S120 List Manual names it “PN/COMM BOARD: No cyclic connection”.	The controller is not running or not configured for this drive Wrong device name or IP address	Check the station name and IP (r61000, r61001) against the controller's configuration Start the controller's cyclic operation
F07220Drive: Master control by PLC missingAck: IMMEDIATELY OFF1	The “master control by PLC” signal dropped while the drive was running.	The PLC withdrew the signal A fieldbus interruption The input set in p0854 is wired to the wrong signal	Check the PLC program and the fieldbus Check the p0854 interconnection
F03505Analog input wire breakageAck: IMMEDIATELY OFF1	An analog input with wire-break monitoring fell below its threshold (p0761).	A broken or loose analog signal wire The 4-20 mA or voltage source failed or is unpowered	Check the wiring to the signal source Read r0752 (what the drive sees) first; measuring at the terminals is live work for a qualified person
F01600SI P1 (CU): STOP A initiatedAck: IMMEDIATELY OFF2	Safety Integrated found a problem and switched the motor torque off (STOP A, Safe Torque Off).	A failed test of the safety switch-off path A follow-on of F01611 (the two safety channels disagree) STO terminals on the power unit set up differently from the drive's safety settings	Never jumper or bypass Safe Torque Off or any other safety circuit Read the fault value r0949; for 9999 work on F01611 first Select and deselect STO, then power-cycle; safety settings need someone qualified for them
F06100Infeed: Shutdown due to line supply undervoltage conditionAck: IMMEDIATELY OFF2S120 only	The Line Module measured a supply voltage below its trip threshold (p0283 × p0210).	Low line voltage or a weak supply Supply voltage setting p0210 wrong	Check p0210 and the threshold p0283 first; measuring the line voltage is live work for a qualified electrician or a power-quality recorder Look for supply dips while large loads start
F06200Infeed: One or several line phases failedAck: IMMEDIATELY OFF2S120 only	The Line Module lost one or more line phases, or could not lock on to the supply at switch-on.	A dip or a lost phase lasting over 10 ms A missing line reactor, or a peak overload on the load side VSM phase order different from the power unit's	Check the supply, the terminals and the fuses Check the line filter and the line reactor Note any earlier alarms A06205 / A06206
F31110Encoder 1: Serial communications errorAck: PULSE INHIBIT ENCODERS120 only	The serial link between encoder 1 and its evaluation module failed; r0949 shows the error bits.	A damaged or unshielded encoder cable, or electrical noise The wrong encoder type set A failed encoder or Sensor Module	Check the encoder cable and its shield connection Check the encoder type in the drive's settings The manual's remedies per fault bit include replacing the encoder, the cable or the Sensor Module
F31885Encoder 1 DRIVE-CLiQ (CU): Cyclic data transfer errorAck: IMMEDIATELY ENCODERS120 only	DRIVE-CLiQ data from encoder 1's Sensor Module to the Control Unit got out of step.	A loose or damaged DRIVE-CLiQ cable A supply problem on the Sensor Module A failed component	Check the component's status LED first; measuring its 24 V supply is live work for a qualified person Check the DRIVE-CLiQ cable, then power-cycle The manual's last step is replacing the component

The name is the message's own short text from the List Manual; “Ack” and the reaction are the manual's defaults. Other codes in the same manuals that this page doesn't cover: F01000, F01001, F01030, F01611, F01650, A01900, A01920, A05000, F06000, F06310, A07012, F07016, A07400, F07403, F07404, A07805, F07950, F30012, F30017, F30022, F30025, F30035, F30037, F30071, F30074, F31100, F31117 – see the List Manual for those and for every code not listed here.

Sources: Siemens, SINAMICS G120 Control Units CU240B-2/CU240E-2 List Manual, edition 02/2023, A5E33839529 (firmware 4.7 SP14) – chapter 4, Faults and alarms; Siemens, SINAMICS S120/S150 List Manual, edition 06/2020, 6SL3097-5AP00-0BP2 (firmware 5.2 SP3) – chapter 4, Faults and alarms. Safety (the DC link discharge time): SINAMICS G120 Power Module PM240-2 Hardware Installation Manual, 08/2017, A5E33294624B AG; SINAMICS S120 Power Units in Booksize C/D-Type Format Manual, 09/2017, 6SL3097-4AC20-0BP2. Read on October 17, 2026.

Meanings, causes and checks are summarized in our own words. The manuals are the reference: they have every code, the full remedies and the safety instructions. Codes, texts and defaults depend on the firmware version, so check the List Manual edition for your drive's firmware.

SINAMICS G120 / S120 parts in stock

SINAMICS G120 and S120 catalog numbers on our shelves right now. Every item is photographed, so check the rating plate – catalog number and version – against the part you're replacing.

6SL3252-0BB01-0AA0Siemens 6SL3252-0BB01-0AA0 Sinamics Safe Brake Module B01 18-30VDC Relay Unit
6SL3120-1TE23-0AA3Siemens 6SL3120-1TE23-0AA3 Sinamics Single Motor Module DC 600V 3AC 400V 30A
6SL3055-0AA00-5BA3Siemens 6SL3055-0AA00-5BA3 SMC20 Sinamics Sensor Module Cabinet-Mounted Drive
6SL3120-2TE15-0AA4Siemens 6SL3120-2TE15-0AA4 Sinamics Double Motor Module DC 600V 3AC 400V 5A/5A
6SL3130-7TE23-6AA3Siemens 6SL3130-7TE23-6AA3 Sinamics Active Line Module 36kW DC 600V 60A 380-480V
6SL3352-6BE00-0AA1Siemens 6SL3352-6BE00-0AA1 C98043-A7600-L5 Power Interface Board Drive Control

Fault won't clear?

When the checks point to the hardware itself – the List Manual's “replace the power unit”, “replace the component” or “replace the Control Unit” – send us the fault code and the catalog number from the rating plate. We check our shelves and our sourcing network and reply with a written quote. Purchase orders are welcome; payment is due before we ship.

Frequently asked questions

How do I acknowledge a fault on a SINAMICS G120 or S120?

Fix the cause first, then acknowledge: set p3981 from 0 to 1, give a 0-to-1 edge on the input set in p2103 (on a CU240B-2 / CU240E-2 without fieldbus that is digital input DI 2 in the factory setting), send control word bit STW1.7 from the PLC, or switch the drive off and on. A code whose acknowledgement is POWER ON needs the power cycle, and Safe Torque Off has to be deselected before a Safety Integrated fault can be acknowledged.

What is the difference between an F code and an A code?

An F code is a fault: the drive reacts (OFF1 ramps down, OFF2 lets the motor coast, OFF3 is a quick stop), records it in the fault buffer and waits to be acknowledged. An A code is an alarm: a warning that clears itself once its cause is gone. Letters in brackets after a code in the List Manual mean its type can be changed with p2118 / p2119.

Are SINAMICS G120 and S120 fault codes the same?

Largely yes. Both List Manuals use the same SINAMICS numbering: the codes shared on this page have the same number in both, and the same name apart from a few wording differences noted in the table. The S120 adds infeed (Line Module) codes F06xxx and DRIVE-CLiQ encoder codes F31xxx; rows marked “S120 only” or “G120 only” appear in one of the two manuals only.

Where can I see which faults a SINAMICS drive had?

r0945 lists the fault codes: the current fault case and the last seven acknowledged ones, up to eight faults each, with r0949 holding each fault's value. r2122 lists the alarm codes, and r2131 / r2132 show the current fault and alarm code.

Can you supply a replacement SINAMICS control unit, Power Module or Motor Module?

Send the catalog number from the rating plate (it starts 6SL3 on G120 and S120 parts) and the fault code through our quote form. We check our shelves and our sourcing network and reply with a written quote.

SINAMICS G120 and S120 fault codes: what they mean and what to check first

Quick answer

Reading and acknowledging a SINAMICS fault

One page for G120 and S120

Common SINAMICS G120 / S120 fault codes

SINAMICS G120 / S120 parts in stock

Fault won't clear?

Frequently asked questions

Send us the fault code

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