JD 490E computer code reading

[Knivens894]

I have a John Deere 490E excavator with two computer modules, each with a red lens to flash error codes. I also have the technical repair manual TM1505. I have found nothing in it to tell me how to read the computer error codes or what they mean. Does anyone know where I can find that information?

 

[Knivens894]

After consulting with my John Deere dealer they were kind enough to print out the pages I needed from this machine's diagnosis manual TM1504. The lower computer is the PCV controller, while the upper is the engine controller. The PCV controller is readable by the user with the aid of one jumper wire and no additional computer is required. The PCV controller was showing 5 different codes. The first was the angle sensor, which I checked to find it was producing a signal of 4.85 V. When it was installed it was producing 4.40 +- 0.03V as the repair manual directed and would not go back to 4.40V so I replaced it with a new sensor. The new sensor was set at 4.40V as the manual directed. The stalling characteristics of the machine were not changed.

The next code related to the pump control solenoid valves, so I checked them with an Ohm meter to find one fairly open at 1,850 Ohms (unload valve) while the other was much lower. I am ordering a new pump control solenoid tomorrow and will install it upon receipt. My question now is: Are all the codes read valid, or would one or two out of range sensors cause other codes to be displayed? If anyone knows I would appreciate the information. The machine has been out of service a week already for this problem. If I must address all the displayed codes, I want to get on with it to put the machine back to work.

Thanks!

 

[Knivens894]

Yesterday, I install the new solenoid valve on the pump controller and solved all the problems. The hydraulic temp had been running on the high side of the range for some time. The machine was losing power and finally started stalling with any attempt to work. With the new angle sensor correctly set and the solenoid replaced, the hydraulic temperature is running much lower and the machine has more power to work. At low idle it will lift the entire machine without struggling. The computers are under a plastic cover behind the seat requiring the removal of 4 screws to access, so it is not convenient to access or read regularly. If you are having higher than reasonable hydraulic temps or lowered capacity to do work, use TM1504 and read the codes to help identify the problem(s).

 

[joelx777]

Knivens - I am years late here, but where did you get a diagnostic computer? Any chance you could send me the manuals?

 

[Steve Jacobs]

I have a problem with my John Deere 490E PVC Controller. With the diagnostic port jumped when I turn the key on the PVC computer flashes once and that is it. Do I have a bad PVC computer? If any one can help answer this thank you.

 

[mg2361]

Welcome to HEF Steve!

You should have started your own thread rather than piggy backing another thread.

First, check all the fuses, especially the 1 amp fuse for the Pump controller and the PVC backup. While you are at it, check all the fuses.

Second, which two terminals did you short together for the code check? Post a picture of the jumper.