6420S Forward/reverser intermittent problem

[jd6420s]

Hello. My 6420s is getting a bit more temperamental with the forward reverser. It sometimes refuses to engage and just the blue light comes on. If I restart the tractor or clear the fault codes it usually engages and is fine for the rest of the day. On one occasion it did disengage whilst I was driving on the road. I returned it to neutral and but it back into forwards and it went fine. Any ideas what it could be?
After clearing the fault codes and running the machine I got the following afterwards.

306 051 04 EPC Transmission enable pressure too low
306 034 31 EPC Enable proportional solenoid valve is opened by mistake
302 123 31 BCU Switch signal from forward or reverse travel does not match the signal from the not-neutral switch

 

[Flat 10]

Is the old style 20 series round one or the newer 30 style paddle lever?

 

[aidan]

Hello. My 6420s is getting a bit more temperamental with the forward reverser. It sometimes refuses to engage and just the blue light comes on. If I restart the tractor or clear the fault codes it usually engages and is fine for the rest of the day. On one occasion it did disengage whilst I was driving on the road. I returned it to neutral and but it back into forwards and it went fine. Any ideas what it could be?
After clearing the fault codes and running the machine I got the following afterwards.

306 051 04 EPC Transmission enable pressure too low
306 034 31 EPC Enable proportional solenoid valve is opened by mistake
302 123 31 BCU Switch signal from forward or reverse travel does not match the signal from the not-neutral switch

which code appears first

 

[Wesley]

I’ve had similar on a 6920s when one of the two speed sensors started playing up. The speeds weren’t matching so it thought something was wrong & put it in neutral with the blue light on. Was a bit of a bugger to diagnose as it was intermittent for a while.
Thoughts I had the codes written down on paper & put in the manual but can’t seem to find them.

 

[jd6420s]

Is the old style 20 series round one or the newer 30 style paddle lever?

It is the newer style paddle type lever.

 

[jd6420s]

which code appears first

306 034 31 - Enable proportional solenoid valve is opened by mistake- appears first.

 

[aidan]

306 034 31 - Enable proportional solenoid valve is opened by mistake- appears first.

followed by which ?

 

[jd6420s]

I'm not sure. They don't come up automatically on the screen. I have to go looking for them when the engine is switched off.
It refused to activate today but I just turned it off and it went okay afterwards. Only the one code came up though.