JD 490E & EX120-2 Engine Controller Compatability

Can anyone tell me if the EC units in the JD 490E and Hitachi 120-2/3 are identical. I know the machines are physically the same but have different engines. I need a new EC computer. When I search for the part number (9109825) most hits are listed for the EX-120. I'd be grateful for any knowledge and information. Thanks, Brian K.

I have often switched Deere and Hitachi pump controllers back and forth but the few times I tried to do the engine controller it didn't work. They were however the 200 to 300 size machines but I would think that it probably wont work. I see that Deere does give the 9109825 as the part number so I have to wonder also if it would work. The old number was an AT158401, if you Google that there are several hits. You have to be very careful with alot of the aftermarket controllers, I've seen alot of them not work properly. One company I have had very good success with is Machinery Parts Warehouse.

If you have a 490E below 24999 in serial number it would have to be a 120-2 controller. Above serial 25000 it would have to be a 120-3 controller. You can't mix and match from -2 to -3 as far as I know because the -3 has sensors that the -2 does not have. Many people listing controllers say they will work for -2 and 3. I say they will not.

excavator said:

I have often switched Deere and Hitachi pump controllers back and forth but the few times I tried to do the engine controller it didn't work. They were however the 200 to 300 size machines but I would think that it probably wont work. I see that Deere does give the 9109825 as the part number so I have to wonder also if it would work. The old number was an AT158401, if you Google that there are several hits. You have to be very careful with alot of the aftermarket controllers, I've seen alot of them not work properly. One company I have had very good success with is Machinery Parts Warehouse.

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Thank you for responding. I bought the machine in Feb (it's a 1992 model year converted by FABETEK to be a tree harvester) but didn't anticipate how complicated these machines are, and assumed Deere parts would be readily available, which their not. The Hitachi/Deere Part/No system only confuses matters. My gut feeling is I could be getting myself into trouble by mixing and matching. I'd hate to drop hundreds on a controller that won't work. I've already spent a ton of time/money trying get this lemon to work. But it's been one heck of an education. I'll check out Machinery Parts Warehouse.

mg2361 said:

If you have a 490E below 24999 in serial number it would have to be a 120-2 controller. Above serial 25000 it would have to be a 120-3 controller. You can't mix and match from -2 to -3 as far as I know because the -3 has sensors that the -2 does not have. Many people listing controllers say they will work for -2 and 3. I say they will not.

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Thank you for replying. It's good to know that the -2 and -3 PVC controllers aren't interchangeable. My machine S/N is 20117 so it should be a EX120-2. But it has an Arm-In pressure sensor which must have been added on at some point (it's not factory wiring) for a -3 PVC. I guess I should remove the controllers a look for their P/N's. I saw some threads suggesting the controllers can be opened up and inspected for burned out components.

The later serial number machines had an extra sensor added on the control valve, if I read the OP he is looking for an engine controller. I don't believe the extra sensors will effect the EC, will they? And I have actually swapped PVC's between -2 & -3 machines with little to no effect on the performance.

mg2361 said:

If you have a 490E below 24999 in serial number it would have to be a 120-2 controller. Above serial 25000 it would have to be a 120-3 controller. You can't mix and match from -2 to -3 as far as I know because the -3 has sensors that the -2 does not have. Many people listing controllers say they will work for -2 and 3. I say they will not.

View attachment 247405

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excavator said:

The later serial number machines had an extra sensor added on the control valve, if I read the OP he is looking for an engine controller. I don't believe the extra sensors will effect the EC, will they? And I have actually swapped PVC's between -2 & -3 machines with little to no effect on the performance.

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My EC is the definitely bad as I get fault code 4. I also get fault 26 which the tech manual states as DP sensor disconnected. I've adjusted DP sensor to factory output V setting and checked the signal/wiring voltage back to PVC box which is OK. I am assuming the PVC is also bad but not positive. The machine runs hot which is the big problem currently, main & pilot pumps run at 160F and CV at 150F after 45minutes. This seems a bit to hot, or is that common? I'm in the process of checking line pressures and relief valves. I found some good threads on this forum regarding troubleshooting this issue. Thanks again.