1995 John Deere 490E Angle Sensor Question

[Price]

I am brand new to this machine and have read most of the posts about the 490e. I purchased the 1504 and 1505 manuals.

The problem is the hydraulics will stall the machine when raising boom, extending stick and opening the bucket. I started with the angle sensor. The sensor on the machine had the wires ate in too by a mouse and the previous owner had repaired the sensor and put it back on machine. I ordered a new aftermarket sensor ($43). JD sensor was $800(maybe the problem??). In the manual it stated that the sensor should ohm at 850 +/- 50. The old sensor read 848 and the new sensor read 123.

I put the old sensor back on machine and followed procedure to adjust sensor. The voltage I saw was 1.5 v. When I moved the sensor the voltage never changed.

Could the original sensor ohm correctly and still be bad? And could the new sensor be good with the ohm reading being wrong/different?

I have not tried the new sensor yet but may give it a try.

I also checked the wiring harness from the PVC to angle sensor and it checked out good. The fuses checked out as well.

The code light is blinking 5 then 4, same speed. Trying to find this in the manual.

Any suggestions as what to try next?

Thanks

 

[mg2361]

The code light is blinking 5 then 4, same speed. Trying to find this in the manual.

Sounds like you are looking at the EC controller light and not the PVC light. The PVC is the bottom controller, and that is the light you should be checking first. A code 5 from the EC means no communication from the PVC.

The fault codes are listed in the hydraulic tests section of TM1504.

Does the light on the PVC blink once a second with the key on?

Stay with the old sensor for now. Your issue may not be the A sensor. Usually stalling issues are one of the pump displacement solenoids or their wiring. Issue with the PVC could also cause stalling.

 

[Price]

Sounds like you are looking at the EC controller light and not the PVC light. The PVC is the bottom controller, and that is the light you should be checking first. A code 5 from the EC means no communication from the PVC.

The fault codes are listed in the hydraulic tests section of TM1504.

Does the light on the PVC blink once a second with the key on?

Stay with the old sensor for now. Your issue may not be the A sensor. Usually stalling issues are one of the pump displacement solenoids or their wiring. Issue with the PVC could also cause stalling.

Thanks for answering. I was looking at the EC light blinking 5 then 4. The PVC Controller light is not blinking. I checked fuses again and they were good. I tried doing diagnostic test by putting wire in data port but no light on the PVC.

One of the displacement solenoids looks to be new. I didn't test the other yet because I didn't know if it would do any good if the PVC Controller is bad.

So would I be safe to say the PVC Controller is bad and order a new one? If so will aftermarket be just as good or do I need Deere?
Thanks

 

[mg2361]

So would I be safe to say the PVC Controller is bad

Not yet. It means the PVC is shut down, either due to a loss of voltage supply/ground, a short in the system (wiring/sensor), or the PVC is defective.

The F7 fuse. First, is it a 1 amp fuse in there and, two, is it good?

If yes, then you have to make sure the voltage supply to the PVC is getting to the PVC. You also have to make sure the PVC has a good ground.

If there is anything higher than a 1 amp fuse in there, then remove the top cover on the PVC and look at the R1 resistor in there (see picture below). If it is burnt, the resistor will need to be replaced and the source of it failing needs to be found.

 

[Price]

Not yet. It means the PVC is shut down, either due to a loss of voltage supply/ground, a short in the system (wiring/sensor), or the PVC is defective.

The F7 fuse. First, is it a 1 amp fuse in there and, two, is it good?

If yes, then you have to make sure the voltage supply to the PVC is getting to the PVC. You also have to make sure the PVC has a good ground.

If there is anything higher than a 1 amp fuse in there, then remove the top cover on the PVC and look at the R1 resistor in there (see picture below). If it is burnt, the resistor will need to be replaced and the source of it failing needs to be found.


View attachment 305854

I will double check but I am pretty sure there is a 3 amp fuse in F7. I will get a 1 amp. All the fuses were showing voltage.

So remove harness and check for power to PVC. I am assuming manual has diagram showing location of power on the harness connector. The ground is the mounting surface of the box? or is it through the harness?

I will check the resistor. Probably burnt since they had a 3 amp fuse installed.

So where do I start trying to find what is causing resistor to burn? I see a test section in electrical in the manual. Maybe start there??

I have never replaced resistors before and I see some resistors with 1% tolerance, 5% tolerance does it matter which?

Thanks!

 

[mg2361]

So remove harness and check for power to PVC

I prefer to backprobe (carefully). Obviously battery voltage at the voltage supply, and less than 0.200 volts on the ground.

The wiring diagrams in the manual will show which wires. There is also a section that shows pin locations for the PVC connector.

I don't remember anything being mentioned about tolerance. I guess I would hedge towards 1%.

 

[Price]

Update...I have changed the fuses on the left side of panel. All fuses have power but I am not able to ground in cab and get 24 v at fuses. Usually about 18 v. If I run a wire from battery ground and check fuses then I have 24v.

I removed the PVC and put a new resistor in. Reinstalled the PVC and EC. Checked for codes with wire inserted in data cable as stated in manual. The codes on the PVC was 28, 4, 5. Code 28 was the P sensor was not plugged in. It was plugged in and I check the wires from the plug up to the PVC and I had continuity. I did not see anywhere in the manual a procedure to check the pressure sensor (P). If anybody that reads this knows which page please let me know.

I checked the PVC harness to the EC harness and had continuity there.

I adjusted the Angle sensor to 4.4 volts. Checked the codes again and had 37, 4, 28 on the PVC. I have no idea what code 37 is. My manual stopped at 36 in the list.

The EC had a code 4.

I ran the machine and it did ok for about 5 minutes then it started lugging down and the engine would try to die. When tracking the machine the movement was erratic. Had to idle engine down to be able to track without it jumping which it was doing this before. The PVC now has no light flashing. EC is flashing 5 then 4. Fuses are good. Basically in the same spot I was in when I started.

There is one displacement sensor on the hydraulic pump that appears to be old. The speed sensor looks to be new. I have not tested either.

 

[mg2361]

Was your original resistor burnt?

Is your serial above or below 25000?

 

[Price]

Was your original resistor burnt?

Is your serial above or below 25000?

The resistor was burnt and serial number is above 25000.

 

[mg2361]

I believe on the higher serial number, the PVC will shut down if it detects a short in the 5 volt reference circuit.

 

[Price]

I don't see anything in manual about a 5 volt reference circuit. I don't understand what that is.

 

[Price]

Also I have read in a post about angle sensor being adjusted at max swash angle. Is that with boom down, arm extended and bucket curled in with bottom flat on ground?

 

[mg2361]

I don't see anything in manual about a 5 volt reference circuit

Nope, you won't.

All the pressure sensors operate on one 5 volt circuit supplying them. That is the reference voltage. If a sensor or the 5 volt reference wire is shorted to ground, it draws the entire system down because that controller only has one 5 volt circuit supplying all the sensors. Newer machines have multiple 5 volt circuits supplying the system so something like this does not happen. Your issue most likely resides in one of the pressure sensors or their wiring.

Also I have read in a post about angle sensor being adjusted at max swash angle. Is that with boom down, arm extended and bucket curled in with bottom flat on ground?

Nope, that is incorrect.

Check your messages for some bathroom reading material

 

[Price]

Thanks for the reading material!

The code I was getting on the PVC was 28 which relates to the pressure sensor (P). The wiring checked ok. Since I don’t know how to check the P sensor I ordered a new one. Has not come in yet.

When I ran the machine last time the pvc shut off after running for several minutes. Since this is a later model and the PVC will shutdown if it senses a short, the instructions said to unplug one sensor at a time until light comes back on and that sensor should be the bad sensor. When I unplugged the angle sensor the light came back on. I had a new angle sensor from Friday Parts so I installed it, adjusted to 4.4v and the machine ran for 20 minutes and the PVC did not shut down. The original sensor ohmed(?) correctly (850) but apparently had a short. I still had several codes, 30, 31, 32 and 37 I believe.

I didn’t want to keep running machine with a bad pressure sensor so I am waiting for it to come in so I can run machine and do some actual digging with it to see how it does. Hopefully tomorrow.

 

[Price]

Update...replaced pressure sensor with no change. Error code (28) still shows pressure sensor not pugged in or bad. Checked harness and had continuity and 5 volts.

So...I operated the machine for about an hour. I dug up two large oak stumps and machine did fair. The travel in turtle may or may not work. Travel in middle and rabbit selection worked fine.

Two days later...

PVC is showing 12 codes. The manual stated that if there were more than 8 codes the EC could be bad?? EC is showing code 4.

Codes showing are 22,25,27,28, 29, 30, 31, 32, 34, 36, 38, 40 on the PVC.

One of the codes is the displacement sensor (dp). I checked for volts with key on 5 volts and with engine running 0.4 volts. According to manual this was correct as far as I understand the manual.

The engine control motor is not working. I tested the harness and the best I can tell is that I have one of the wires without continuity. it was either the power or ground I forget which. I tested the engine control sensor and it also had one wire that did not show continuity, again power or ground.

So do I change out the EC or continue otherwise? Like the DP sensor, it checked voltage wise but I am still seeing code. Really don’t know which direction to go. I am going to clean the machine and check grounds if I can find them and also the relays in cab. Also where the cab harness and outside(?) harness from sensors plug in. I believe this is at junction box maybe in cab.

 

[Price]

So I checked the two fusible links that are in the battery compartment by removing battery cables and then checking the links visibly and by continuity. I reinstalled battery cables and went to look at codes again and the PVC is not responding and the EC is flashing 4 then 5. The same place I started basically.

I checked the fuses and they were fine. I have not checked the resistor in the PVC again but the 1 amp fuse is not blown.

 

[mg2361]

At this point it would be nice to be able to plug in MPDr. See if the PVC communicates at all, and what feedback you get from the sensors.

All fuses have power but I am not able to ground in cab

You mentioned you checked voltage supply to the PVC, but did you check the ground to the PVC by backprobing and measuring the voltage on that ground?

If the power and grounds to the PVC are good, then yes, I think you may have a bad PVC. My concern is that resistor. If it blew, then something external caused it, either a sensor or wiring short. Even if there was too high a fuse in there, the system when operating properly, should not consume more than 1 amp. So something caused the excess current. So I would be worried if you replaced the PVC, would it last? I would think as long as there is a 1 amp fuse in there it should protect the PVC.

You won't be able to buy one from Deere. If you shop for one, make sure it is compatible with your serial number.

 

[Price]

Thanks!

I will double check the ground and power to PVC by backprobing. I was able to ground to cab and check the fuses again, all were at 24v, either on the left side of fuse or the right.

When I checked continuity on EC Motor and the EC Motor sensor, one of the wires didn’t pass the test both. I was getting 5 volts but not continuity on either the ground or power. Possibly a short in that wire(s) causing a shut down??

My plan is to unplug sensors and see if light comes back on.

At this point should I consider a hydraulic bypass kit?

 

[mg2361]

When I checked continuity on EC Motor and the EC Motor sensor,

What ever you do, never plug and unplug the EC motor with the key on. That WILL ruin the PVC. Something that is not readily found in publications.

At this point should I consider a hydraulic bypass kit?

I cannot answer that question. I have never installed one, nor have I come across one. From what I have read in the forum here, they sound problematic, at best.

 

[Price]

Thanks again! If I can’t get PVC to come back on then will try new one I guess. I don’t think we unplugged or plugged the EC Motor in with key on but with all the checking and probing it could have happened. I didn’t see that about the EC Motor but I saw it about the EC I’m thinking.