XC43 multiple DOUT overloads

We are having a problem with XC43 giving overload errors in multiple DOUT's at the same time.

Construction of the application is MD4 + 2xMC43 + 3xXC43, running with IQANdesign 6.08.

Problem is only in one of those XC43's. We use those DOUT's to control two different kind of solenoids, connected as shown below:

Fault codes are occurring only in:

• C2:29 (load 0,83 A), C2:13 (0,83 A), C2:30 (1,29 A) and C2:14 (1,29 A) overload simultaneously
  • If you activate only one of these DOUT LS's, every one of those are giving fault code
• C1:58 (1,29 A) and C1:42 (1,29 A) overload simultaneously
  • If you activate only one of these DOUT LS's, both of those are giving fault code
• C1:60 (1,29 A) and C1:44 (1,29 A) overload simultaneously
  • If you activate only one of these DOUT LS's, both of those are giving fault code

Sometimes you can drive a day without having any fault codes, sometimes fault codes appear at the first activation at the morning. Even when the machine is standing still, only ignition on and you are activating those solenoids, it can be that you can activate those 50 times without problem and then suddenly the next activation gives you the fault codes.

We have replaced that XC43 with the other one installed in the same machine, still giving the fault codes. The original XC43 didn't give any fault codes when installed to another location. We have checked and measured all the wires, not shorted to the ground or to each others. Measured the coils, everyone has the correct resistance. Replaced all the diodes at the solenoids' connectors, no change. We have dozens of machines with exactly same construction and none of those are having the similar problem.

Any ideas how we should proceed with the troubleshooting? Thanks!