Discussion:
error code A3907 Still rx50-15. year 2004

Hello everyone, I'm working on a Still RX 50-15 forklift Serial No : 515054004073 2004. The vehicle is experiencing a problem where it won't move, displaying error code A3907; the hydraulic system is still functioning. The vehicle allows for direction selection and the direction indicator lights are on in both directions; however, after about 3 minutes, the main contactor releases itself.what I have done is check the drive motor, speed sensor, sensor temperature, cable and all ok. maybe there are friends who have had this problem we can share information. thank you
  • Posted 13 Aug 2026 20:41
  • By nguyen_t
  • joined 17 Jan'19 - 11 messages
  • Viet Nam
Showing items 1 - 3 of 3 results.
Hi Nguyen, does sound like traction converter may have failed then?. Impedance should be either around 60 ohms or 120 ohms. Does sound like internal power supply failure if no supply for speed sensor though, so possibly no internal power for logic either.
  • Posted 24 Aug 2026 15:28
  • By simon_k
  • joined 31 Oct'04 - 149 messages
  • Devon, United Kingdom
Hi Simon, thanks for the reply.
I checked and confirmed that pin 1 of the inverter has power (24V) when the keyswitch is turned on, but pins 3 and 5 (speed sensor power supply) show only 1.8V. What should the impedance be between pins 10 and 11?
  • Posted 22 Aug 2026 16:54
  • By nguyen_t
  • joined 17 Jan'19 - 11 messages
  • Viet Nam
Hi nguyen, Error is CAN comm issue with Traction inverter. Check can impedance between pins 10 and 11 on inverter. Check inverter has power at pin 1 keyswitch pos, main large neg. Worth checking small lithium battery in dash display also (behind round black cover on back).
  • Posted 21 Aug 2026 16:16
  • By simon_k
  • joined 31 Oct'04 - 149 messages
  • Devon, United Kingdom

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