Siemens SINAMICS V20 VFD
Siemens SINAMICS V20 VFD code F12: Converter temperature signal lost
The converter heat sink temperature sensor has a broken wire, which causes the drive to stop the equipment.
- Code
- F12
- Name
- Converter temperature signal lost
- Controller
- Siemens SINAMICS V20 VFD
- Type
- Sensor open circuit
- What it does
- Fault: the equipment trips and stops
- Risk
- YELLOW Booth plays by its own rules
- Reset
- Needs a manual reset
- Source
- The manufacturer's manual (subscribers see which manual and page)
Updated November 4, 2026
How to fix it
Subscribers get:
- What to do next, in plain words
- Which manufacturer manual it comes from, linked
- The 1 common cause listed for this code
- The step by step check for this problem, one check at a time
- Booking a live video call with Ben, a master booth technician ($250/hr, paid per call)
Questions about this code
What does Siemens SINAMICS V20 VFD code F12 mean?
The converter heat sink temperature sensor has a broken wire, which causes the drive to stop the equipment.
Is Siemens SINAMICS V20 VFD code F12 dangerous?
It is graded yellow: not hard, but a booth does it differently than the gear most techs know, so follow the checks in order.
How do I fix Siemens SINAMICS V20 VFD code F12?
The manual's fix and the step by step check for this code are in WERCS Diagnose, plans from $49 a month. For help right now, WERCS answers 24/7 at (877) 489-3727.
Other Siemens SINAMICS V20 VFD codes
F4 · Converter overtemperatureF5 · Converter I2tF6 · Chip temperature rise exceeds critical lF11 · Motor overtemperatureF20 · DC ripple too highF23 · Output current ripple too highF35 · Maximum number of auto restart attempts F41 · Motor data identification failureF51 · Parameter EEPROM faultF52 · Converter software fault