Error Code 73 - 2012 John Deere 4720

[fleminj2pa]

I have a new 2012 JD 4720 cab tractor that gave me a warning message tonight on the way back in after about three hours of tilling. The warning light came on intermittently and it was Error 73. Interesting that the owners manual error codes only go up to 72. Anyone have any info on this?

 

[dconine]

I had the exact same problem that you have on our '11 John Deere 4520 cab. It was only a month old when the problem occured and was intermittent. Dealer looked at it and fixed it in a couple days.

It ended up being the ground cable that runs from the battery to the frame. It is bolted onto the frame and there is some other smaller cables bolted to it as well. Apparently the paint needs to be cleaned off under the cables where it hooks to the frame to get a better connection. If you clean that paint off, that will probably fix your problem.

Let me know how you get along. Good luck!

 

[fleminj2pa]

Thanks for that information. I'll check that and let you know if I find anything. I figured it would be something simple and my dealer is 100 miles away. You've been very helpful!

 

[wacummins]

Hello I have the same problem with my my2011 4320 cab tractor. I have cleaned and protected both ends of the neg cable and it's still doing it. I ordered the manual but I don't have it yet. The error flashes any time I put a high load on the system, turning up the heater fan gets it, turn on all the lights gets it, most of the time too, and if I do both it always turns it on.
I'm going to load test the battery to make sure it's not the problem. Of course the tractor starts up just fine so I don't think it's the starter, I will check the positive lead on the starter though....

Any other ideas??

Thanks
William....

 

[BigMike50]

found the code 73 from another search to be :
engine starter motor relay - starter output is shorted to battery or open circuit.

 

[fleminj2pa]

My problem turned out to be a bad wire in the top of the cab. They had to take the headliner out to get to it. If memory serves me correct it was a wire to the fan speed switch on the A/C.

 

[wacummins]

My problem turned out to be a bad wire in the top of the cab. They had to take the headliner out to get to it. If memory serves me correct it was a wire to the fan speed switch on the A/C.

'

Interesting I wounder if that could be my problem too, as it is effected by the fan switch. I can also almost swear that I hear a shorting sound when I engage the high load devices into operation.... Anyway I tested the battery at 200 amps draw down for 15 seconds and it maintained a 11.9 V output, and as I don't know the CCA for the battery I didn't test it higher, I think the battery is probably not the problem.
I have been wanting to take the roof off and now I have a second excuse to do it ( the first to clean out the evaporator from the dust getting past the cab filter).

Thanks for another idea to check out!

William.....

 

[sd455dan]

Hello I have the same problem with my my2011 4320 cab tractor. I have cleaned and protected both ends of the neg cable and it's still doing it. I ordered the manual but I don't have it yet. The error flashes any time I put a high load on the system, turning up the heater fan gets it, turn on all the lights gets it, most of the time too, and if I do both it always turns it on.
I'm going to load test the battery to make sure it's not the problem. Of course the tractor starts up just fine so I don't think it's the starter, I will check the positive lead on the starter though....

Any other ideas??

Thanks
William....

Your tractors symptoms, sound like the ecm (assuming it has one) is either monitoring a voltage drop or what it thinks is excessive current flow in the tractors electrical accessories circuit ... I have seen very similar symptoms- different code...obviously, in newer automobiles but these new tractors are getting pretty high tech

If they are like the auto manufacturers, my guess would be that JD has already released a TSB (technical Service Bulletin) for the dealership on how to correct this problem... and as with many TSBs sometimes there are more than just one possible cause.. so it maybe a list that they go thru in order until the problem is completely eliminated..

One thing you might try in addition to the test you already mentioned, would be to monitor the voltage while the engine is running and look for a voltage drop that is excessive, when switching on the electrical loads, most computer controlled and monitored alternators are capable of handling different loads with little variance in system voltage.. my 02 cents

 

[mjncad]

I have been wanting to take the roof off and now I have a second excuse to do it ( the first to clean out the evaporator from the dust getting past the cab filter).

Thanks for another idea to check out!

William.....

Be careful taking the roof off and putting it back on that you don't damage the seal. That is a common problem that will affect your AC system's ability to pump out cold air when you need/want it. There are numerous posts on TBN and elsewhere about damaged roof seals.

 

[LindenBruce]

Thats interesting that the manufacturers arent using automotive OBD codes to simplify the diagnostics when a problem does show up. B