Hello all, I recently purchased a Joh Deere 490E without doing enough research apparently. Machine starts and runs great but anytime a hydraulic function is run until relief the engine will bog down and stall. Have down some reading and testing. I am pretty much getting no voltage to any of the sensors/solenoids on the pump. I have 5v on the pressure sensor and angle sensor. 0.2 on the speed sensor. 0v on the rest. The machine also has the throttle rigged up with a cable as the factory button does not work. Lastly the light on the bottom computer being the seat is steady blinking and all fuses are good. Any help/advice to fix this would greatly be appreciated. One last thing to note the tracking is incredible weak will not break either track loose on its own. if you are tracking straight on flat ground the machine does track extremely fast it seems and no different in turtle or rabbit. Not sure if this is a separate issue.
The top controller is the EC (engine controller). The EC needs to be powered up (led lamp blinking) to have any chance to solve the engine stalling when hydraulics are over releif. The EC sends the engine speed signal to the PVC (bottom controller). Double check the 1 amp fuses #2 and #5 are good. A short of the “N“ speed sensor will also cause the EC led lamp to stop flashing. Check the resistance of the N speed sensor , spec is 810 +/- 240 ohms. Using the multimeter measure AC volts across the N sensor terminals. The N sensor output voltage should increase as the engine speed increases.
Ok the EC has no light at all on. Fuses are definitely good. I checked the 4 wires between the ec and pvc. I am only getting 0.2 v at the speed sensor when unplugged. I haven’t ohmed it. This evening I also read the codes through the pvc blinking light . I have code 20, 26, 28, and 29
I am thinking if I can resolve 20 that may take care of the others? Not sure how to diagnose 20
Check that the N sensor resistance is in spec. Remove the top cover from the EC and check for any burnt components or obvious damage.
Good resistance no damage. Looks new
No Led lamp light on top ec controller
The EC looks new? The EC lamp light doesn’t exist or it’s not working ?