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Cat 277b ECM, need help

J

Jasonbowling

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Mar 30, 2019
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10
Location
Kentucky
I have a 2005 cat 277b skid steer. Had it about a month. While running it the seatbelt/lap bar light would come on. This would kick the parking brake on also. The parking brake light would be solid but the seatbelt woild flash. Once the flashing light went solid I could hit the parking brake switch and keep working. It was stating to happen more often, about once every 5 minutes. I also have an enclosed cab, so I dont want it to keep me from operating it while the arms are up. Dont want to have to do the rear window thing to get out!

So I tore it apart, when I pulled the ecm out.from under the floor. The plug, wires and ECM are dry. I unplugged the ecm connector and a yellowish fluid began filling the ecm area where the plug goes. The plug also had yellow fluid on it. Doesn't appear to be hydraulic fluid either. So did something let go inside the ecm???
 
J

Jasonbowling

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Mar 30, 2019
Messages
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Location
Kentucky
Forgot to add, it has roughly 2700 hours and s/n mdh03121. Heres a picture of the ecm after I pulled the plug. There was not much fluid in there, but as it sat, it filled up more!
 

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Nige

Nige

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It's come up a number of times in the past that a "hardened" bottom seat cushion (very possible on a machine that's 14 years old) can prevent the "operator present" switch inside the seat from functioning correctly.
Take a look at that would be my first suggestion. Switch is #2 on the diagram below. If it needs a new switch it's not the end of the world. Part Number 154-3986. Price about $8.

upload_2019-3-30_16-17-56.png
 
J

Jasonbowling

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Kentucky
Any thoughts on the fluid in the ecm? I'm figuring a capacitor or something fluid filled has let go inside the ecm shorting it out? I have tested all my tool and polit solenoids prior to finding the ecm. I was following the cat trouble shooting paperwork for a unit while operating that was the seatbelt light flash. When it does it, I do everything. Lap bar up and down, hop in the seat, open and closed the door, cuss and look like a goof. Would love to see I video of me when it happens!

Nige said:
It's come up a number of times in the past that a "hardened" bottom seat cushion (very possible on a machine that's 14 years old) can prevent the "operator present" switch inside the seat from functioning correctly.
Take a look at that would be my first suggestion. Switch is #2 on the diagram below. If it needs a new switch it's not the end of the world. Part Number 154-3986. Price about $8.

View attachment 194610
Click to expand...
 
J

Jasonbowling

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Kentucky
Nige said:
Have you tried pulling apart the bottom cushion of the seat and operate the switch manually, or even just bypass it for testing purposes..?
Testing the seat switch, door and lap bar are tested if you you start the machine and it is on. When I first start it its fine after about 5 minutes if using it, the seatbelt light starts flashing. Did you see the picture of the ecm? It is full of some type of fluid. That fluid came from inside the ecm, the whole.outside of the ecm and the plug and wiring were dry


AFAIK there is no component in the ECM that has fluid in it.
Click to expand...
 
Nige

Nige

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I can only repeat that AFAIK they are no liquid-filled components in the ECM. However I'm also going to ask a couple of other knowledgeable people and see what they say. I'll let you know but it may not be for a couple of days.
Can you check if the ECM starts to get hot relatively quickly after a cold start-up. That would tend to indicate that something's gone AWOL in an internal ECM component.
Another thing to point out is that the ECM is located under the floor in an area that often gets full of trash, including liquids. The ECM harness connectors are NOT liquid-proof despite people assuming that they are. Thinking out loud what would happen if a hydraulic hose blew at some time in the past and saturated that compartment with oil and some of it leaked into the connectors and into the ECM..?
 
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J

Jasonbowling

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Mar 30, 2019
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Location
Kentucky
I had wondered that too. It doesn't appear that some fluid leaked in. The fluid doesn't smell like hydraulic fluid. Almost smells like fluid from a electric transformer on a pole. I'll will let you know what cat says Monday. Going to take the ecm to them.

Nige said:
I can only repeat that AFAIK they are no liquid-filled components in the ECM. However I'm also going to ask a couple of other knowledgeable people and see what they say. I'll let you know but it may not be for a couple of days.
Can you check if the ECM starts to get hot relatively quickly after a cold start-up. That would tend to indicate that something's gone AWOL in an internal ECM component.
Another thing to point out is that the ECM is located under the floor in an area that often gets full of trash, including liquids. The ECM harness connectors are NOT liquid-proof despite people assuming that they are. Thinking out loud what would happen if a hydraulic hose blew at some time in the past and saturated that compartment with oil and some of it leaked into the connectors and into the ECM..?
Click to expand...
 
Nige

Nige

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Best suggestion that came back was the possibility of a gel-filled component that may have either cracked or overheated and burst the containment. That makes sense.
I don't think you'll get much joy out of your local Cat dealer store, they'll just condemn it and want to sell you a new one.
 
laycobeau

laycobeau

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The only thing inside the ECM is two or three electrolytic capacitors there is not enough jelly in them to make that much mess.
I would bet 100 to 1 it is from outside. I go with Nige on the switches or bad wire.
 
Nige

Nige

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Most of my contacts in the Cat world said a straight flat out no to fluid-filled components inside an ECM....... only the one guy came back with the gel-filled component and TBH I think he was playing Devil's Advocate.

Better believe Beau, he rebuilds/repairs ECM's. I've seen inside a fair few of them over the years but as far as how they work that's Black Magic as far as I'm concerned.
 
J

Jasonbowling

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So we will see what happens. Reman ecm ordered. Spent better part of 6 hours cleaning and checking wire harness today. Should have it in the am and installed and back running with in a few hours. I will say caterpillar made it easy to work on. I have worked on other units that takes you hours to do one thing because they made it a PIA to work on. Updates tomorrow after ecm installed and tested for a while.
 
G

grandpa

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Well good luck to you. I know if I was doing it, before I got it done i'd prolly have smoke coming from somewhere in the bucket.
 
Tags

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Jasonbowling said:
.....I will say caterpillar made it easy to work on. I have worked on other units that takes you hours to do one thing because they made it a PIA to work on. Updates tomorrow after ecm installed and tested for a while.
Click to expand...

The "easy to work on" part made me chuckle. Just wait till a hydraulic line blows to one of the drive motors or a line blows deep in the belly of that Cat, that will change your opinion really fast. At least that's how I felt about mine...:eek:
 
Nige

Nige

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Jasonbowling said:
So we will see what happens. Reman ecm ordered. Spent better part of 6 hours cleaning and checking wire harness today. Should have it in the am and installed and back running with in a few hours. I will say caterpillar made it easy to work on. I have worked on other units that takes you hours to do one thing because they made it a PIA to work on. Updates tomorrow after ecm installed and tested for a while.
Click to expand...
Worst part of Reman is that you never get to find out what was wrong with the old unit.
 
J

Jasonbowling

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So today was challenging. Picked up new ecm this am then dropped off wife's truck to get warranty work done. Home at 11am to realize the isolation mounts in left in the old ecm. 1.5 hr run trip back to cat! But once back home, buttoned up and running in 45 minutes! Ran for an hour and pushed it somewhat harder than I ever have and no seatbelt light flahing!!!! I think I found the issue, reman ecm was 3 grand with tax. Only used one I could find was in Mexico! Dont trust that!

On a side note, I'm a full time firefighter/paramedic. Need your thoughts. About a 5 to 6 weeks ago we made a run for a 39 year old male. He had passed away from a seizure. In the driveway is a 248b sitting on 3 flats. Would it be wrong to stop in STREET clothes and not say anything about me being on the scene when her husband passed and see if she might sell that one to me? It appeared he was working on it, instrument panel is hanging down. The ecms, engine and multiple other parts fit my 277b. Thinking it would be nice to have a spare parts machine if the price is right.
 
J

Jeremy Sailee

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Jasonbowling said:
Forgot to add, it has roughly 2700 hours and s/n mdh03121. Heres a picture of the ecm after I pulled the plug. There was not much fluid in there, but as it sat, it filled up more!
Click to expand...

Hi Jason, I am new here but almost have the same issue as you. Where is the ECM located? I have a 277B 2006 Model. Is it under the seat or the floor board in front of the seat? What do I have to remove to get to it if you have time to let me know. I don't know how to raise the cab. thank you, Sir.
 
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