New Holland L230 skidsteer fault code 4431

[The Nitro]

Hi,

The machine has 115 hrs on it and developed fault code 4431. Sometimes the code displays as soon as the operate button is pressed at cold start and other times it would display after a few minutes work.

Ive had the machine since new and after about 70 hrs i noticed every other day it would beep and display the hydraulic symbol for a second or two at cold start without displaying any fault code so it appears whatever it is has gradually been getting worse over time.

Has fresh filters and oil.
Machine has no symtoms that i can feel or hear from the seat.
One time the hydraulic symbol light up along with the park brake symbol flickering a few times before staying lit along with the beep and code 4431 showing, which happened after say 5 minutes work but cleared after giving it a few hundred more rpm. Only to come back up again a few minutes later and no amount of rpm would make the code disapear.

I have put the machine on a slope and when the fault is present with both park brake and hydraulic fault icons lit... I have noted the park brake works as per normal when button is pressed. I dont have the service manual but i got a few pages printed off regarding the 4431 fault and it suggests either:
Ecm, wiring, charge pressure, park brake solenoid or the park or charge pressure switches may be faulty.

Is there any thing i can do to try to find out the fault myself before getting the dealers out to put their diagnostics on it?

Thanks

 

[The Nitro]

I found the problem. Tested the charge pressure at the brake lines and there is 400psi while machine is running in operate mode at idle and zero psi when park brake is applied so that means the park brake solenoid is working and allowing pressure into brakes and brake switch circuit.

I spliced into both wires of the brake switch and tested for continuinity across the switch at zero and 400 psi and both tests revealed open circuit. When i touched the wires together in operate mode the fault cleared. I then turned the park brake on and touched wires together and fault reapeared in park mode instead of the usual fault only showing in operate mode. The ecu expects to see switch pressurised and continuation in operate mode and open circuit across the brake switch in park mode.

The brakes release at 218 psi and the brake switch is rated at 225 psi but even with 400 psi the switch fails to do anything so I rang the dealer, went through my diagnostics with them and they are sending me a new switch under waranty and i will put in on. It costs $270 for the switch and the dealer is 600km away so finding the fault myself saved a bit of time and freighting machine back to dealer.

Thanks for the help cheers,