Hi am new to the forum. I have a 2005 Caterpillar 277B that I recently bought that came with a bucket. Just over the weekend I bought a brand new grapple and went to hook it up and I have no auxiliary hydraulics. I've been reading everywhere to look into the thumb wheel switch and test that but I found the 4 pins for it just don't know which one to test and where. Also is there anything else I should look for? Solenoids? Relays? All the fuses are good. I would really appreciate the help, I am stuck without the grapple. Thank you in advance.
Hi. first off serial number please. do you have any fault lights on?. do you have the optional right hand display console? Just be aware The auxiliary ECM has been known to fail on these machines however there are a few simple tests you can do to try and isolate the problem. 1/ lift the cab hook a LED test light across one of the aux solenoid coils with enough lead to reach the in to the cab with the back in its lowered position operate the machine and check the status of the test light if it comes on while operating the machine yo may have an hydraulic problem 2/ gain access to the 12 in connector for the RH joystick and check that you have power between pin 1 (8 vdc) and pin 2 ground return. if no power you need to check that the ECM battery voltage between pins 1 and 3 at the ECM.if no power at the ECM you have a possible harness problem which will need to be addressed. 3 /If all this is ok, next check that you have a signal coming out of pin 3 at the 12 pin connector (check with multimeter set on duty cycle setting and connected to pins 2 and 3) while moving the joystick you should have a varying duty cycle reading. 4/ if that is ok you need to check the duty cycle output from the ECM between pins 42 and 58 and 42 and 40 . 5/ if ok check the duty cycle at the control valve aux solenoid coils using extension test leads that will reach in to the cab 6 if this is ok check the resistance of the control valve aux solenoid coils if there is no output at the ECM and you are positive that you have good power and good earths there iis only one thing lef to do before condemning the ECM and that is to try to reflash the ECM unfortunately unless you have a dealer version of ET you cant do it your self have included an electrical schematic if you need additional info please ask
Mark250, Thank you for the reply! The serial number is CAT0277BEMDH02115. I do not believe I have any fault lights on. When the machine is running I have no lights on the dash. I do not believe I have the optional display console. Where are the aux solenoids? Are they on the hydraulic block under the cab? Between pin 1 and 2 on the right joystick that is for the thumb wheel correct? Do I move it up and down to test it?
Also I don't have a led test light. I can go buy one If needed. I only have a bulb one but I do have a power probe if that would work. Thanks
Hi just tried to test the solenoid. Which solenoid do I test A1 or A2? Do I keep the connectors connected and then splice the wire or is there another way? Also doesn't the button on the far left do something? I know I press the button under the horn and then it should enable the aux hydraulics?
yes under the cab you don't need to move thumb wheel to check 8 volt supply at pins 1&2
the output from the ECM is digital. a non LED test light can cause an additional fault due to excessive current draw giving misleading results as for the power probe I honestly don't know much about them and for that reason I would not use it
check both solenoids one at a time. you leave them connected and back probe with paper clips or you can purchase special probes that fit in the back of the connector moving the thumb wheel one way will active one coil moving the other way will active the other coil
the button on the far left is for pressure release in the aux hydraulic lines not sure what you mean by button under horn, are you meaning the left hand joystick horn button and the cont flow button the auxiliary/high flow switch is as circled here is brief circuit of aux switch and connections to ECM to operate one of the contacts must be grounded for either standard flow or high flow Mark
Thanks mark for all the help so far. However, I do not have button #10 does that matter? Also to check pin 1 and 2 on the thumb wheel I leave every connected right and back probe that also? Thanks!
yes .Button #10 will only be there if you have the high flow option, just means you have standard flow only. sorry about my first reply lot of typos in there. Mark
No problem I really do appreciate the help. Great forum so far! I need it working by this weekend so that's why I am in such a rush. So how exactly do I test the solenoid? I backprobe the led test light to both pos and neg on one at a time. Then I lower the cab and turn it on, turn off parking brake, hold the button below the horn, bottom left for 3 seconds then release. And then I should see it light up if it's functioning? Or do I have to move the thumb wheel too? Sorry for all the questions. I'm decent with electrical but this is the first skidsteer I've owned.
if you have the joystick similar to the one below. the button below the horn is for cont. operation and there is no need to use it for normal operation of the thumb wheel. you just need to move the thumb wheel and the leds and or function should work Mark
Ok thank you! Yes that is the joystick i have. I just bought a "computer safe" led test light I will test it in a couple hours when I am near the machine.
Ok I accidently bought a logic probe. It's a led test light with a probe and then pos and neg alligator clips at the end of it. Not sure if that would work so I put paper clips in one solenoid like this and checked for power with my meter while moving the thumb wheel and I have no power. Am I doing something wrong or should I move onto the thumb wheel? Thank you
Also what's your thought on a product like this? I know it's not genuine but if it works it works. Thanks mark.
Also just checked pin 1 and 2 for power with my meter. I turned the key, engine off and got 8 volts.
Just checked pin 2 and 3 on duty cycle for anything and with the key on and with engine running I get 3.6v and that's it. I move the thumb wheel both ways and I do not a change if that's what I have to do.
sounds like a good deal, but check that it has the ET program it may just be the comms adapter kit
good so far, means that you have power to ECM and that it is powering the joystick mark
are you using the duty cycle /percentage setting on multimeter? if you are, check with the signal wire removed from connector and recheck. The percentage should change, if not sounds like a possible faulty module in joystick Mark
Not sure I am using this setting. I have the same meter. If it is a Faulty module in the joystick then you think it's the thumb wheel not working?
Also if I am doing it right with the meter, please correct me if I'm wrong but anyways, if I remove the signal wire #3 correct? How do check it after the signal wire is removed. Thanks
this meter doesn't have the duty cycle function hook a meter that is capable of duty cycle measurement to pin 2 and the signal wire from the thumb wheel that is disconnected .this is just to eliminate any external influence on your reading mark
Hi I don't think I have access to a meter with that function I'll check anyway later this morning. Are you leaning more toward the thumb wheel? If I cannot come up with one is there another test I can do? Thanks
Is there any way that I can possibly cross a few wires using a toggle switch to by pass the thumb wheel to see if that is the problem. I am about to just buy a new joystick because I do not have a meter thay can do the duty cycle. Let me know thank you
the output signal from the thumb wheel is very small and difficult to measure any other way the cost of a joystick is very expensive and you need to be very sure of your testing procedure Mark
Ok what is your recommendation? Try to get a duty cycle meter and check pin 2 and 3 with the connector disconnected. Are you leaning more toward thinking it's the thumb wheel? Thanks
Also when I check it do I move the thumb wheel up and down? Thanks
I bought a duty cycle meter from the snap on guy today because I knew I would probably need it in the future anyway haha
Connector is disconnected and I am testing pin 2 and 3 on duty cycle mode. I am moving the thumb wheel up and down and do not get anything. Am I doing it right? Thanks!
Sorry for blowing this thread up but I reread what you said. So I keep everything connected I just disconnect #3 from the connector and I put one lead on #3 and then I put one lead on #2 that is connected to the system and I turn the key on. I see 045.0 and I move the thumb wheel up and down and do not get a change. Thanks
hi, the meter is set to frequency (hz) not duty cycle Mark
I know but I pressed hz/duty button until I saw the % symbol and then I got that reading. What setting should I put It on and also the reading should be. I'm guessing it should change as I move the thumb wheel correct? Thanks
I'm not sure what setting to put it in but I put it on the voltage setting and got the same reading. Thanks
this is one of my meters and it is set on duty cycle and the symbol in top right hand corner is the percentage sign(%)
Weird meter, but yeah that looks like duty cycle and 45% may well be neutral on that machine, or close enough to be in the deadband?
Hi,my apologies if I misread the photo but it looked like it was the hz symbol. if that's the case it looks like your joystick thumb wheel is faulty.(you did check the signal wire coming from the joystick right) this is assuming that it is the original joystick and the ECM is configured to support that joystick,
Yes I unplugged the #3 pin and then i left the connector plugged in. I then turned the key to the on position and I put the positive lead on #2 and then I put the negative lead on #3 wire that is disconnected and then got that reading. So you think of should buy a joystick today? Thanks
Ok I will let you guys know. I desperately need the grapple working for this weekend so I overnighted the part $500!! Well at least if it works then we will all be good. If not looks like I have a new joystick :beatsme
Mark do you know of any other tests I should do before I get the joystick tomorrow to know for certain? Thanks!
that's all I can think of. if moving the thumb wheel doesn't change the duty cycle signal it appears to be faulty. as lantraxco suggested earlier its possible the rocker is not moving out of the dead band (cantered position) Mark
OK thanks mark! I will let you know today how it goes when the part comes. Thanks again
I got the new joystick today and changed it over and it works great now. Thanks!!
that's great to here Mark
I followed one of your threads regarding a skidsteer with hydraulic issues. I have a 2003 cat 277b. The machine is working well and the arms and all other hydraulics are working fine. The implement hydraulics however do not. they will intermittently work at best in one or both directions from the thumb roller. I did the following from your thread: 1/ lift the cab hook a LED test light across one of the aux solenoid coils with enough lead to reach the in to the cab with the back in its lowered position operate the machine and check the status of the test light if it comes on while operating the machine yo may have an hydraulic problem (did not come on) 2/ gain access to the 12 in connector for the RH joystick and check that you have power between pin 1 (8 vdc) and pin 2 ground return. if no power you need to check that the ECM battery voltage between pins 1 and 3 at the ECM.if no power at the ECM you have a possible harness problem which will need to be addressed. (had the voltage) 3 /If all this is ok, next check that you have a signal coming out of pin 3 at the 12 pin connector (check with multimeter set on duty cycle setting and connected to pins 2 and 3) while moving the joystick you should have a varying duty cycle reading. (results were 50%-53%) 4/ if that is ok you need to check the duty cycle output from the ECM between pins 42 and 58 and 42 and 40 . (1.4% with no buttons pressed is this normal?) 5/ if ok check the duty cycle at the control valve aux solenoid coils using extension test leads that will reach in to the cab 6 if this is ok check the resistance of the control valve aux solenoid coils (the front solenoid coil nearest the front of the machine without pressing roller button 66.6hz,.6% duty cycle, and 61% with button pressed(note: this time when i pressed the button it worked but stopped working shortly after). The back solenoid coil i checked and it read 590HZ,1.4% with and without pressing the roller button.) note: the roller button has over the course of the last week or two worked spontaneously both rolling forward and back this is as far as i got with your list of items to check. what are your thoughts? thank you for your time in advanced if there is no output at the ECM and you are positive that you have good power and good earths there iis only one thing lef to do before condemning the ECM and that is to try to reflash the ECM unfortunately unless you have a dealer version of ET you cant do it your self have included an electrical schematic if you need additional info please ask
Hi looking at this I have a typo that may have confused you. where it states to move the joystick should be move the rocker switch backwoods and forwards see how you go and let me know Mark
Yes we did that and got between 50-53%
In that case I would recheck your work to make sure of the electrical side and then see if the actual roller wheel is moving the switch. if it is you have a bad rocker assembly mark
So just to confirm you want me to check the duty cycle across pins 2 and 3 on the plug that goes to the rh joystick thumb wheel while moving the thumb wheel forward and back?
Yes
I tested it again and it started at about 50% then jumped to 80% and down to 20%. the wheel worked in one direction. Then the wheel stopped working all together. Then the reading stayed at about 50%. I figured it would be the handle, so i replaced the handle. With the new handle installed the roller wheel will work in the forward position every-time without issue. (the 4-5 startup and stops i tried it on)However nothing in the back position. I went to test between pins 2-3 like i did previously however i am having trouble getting a reading due to the new plug being smaller. Previously i was able to stick probing needles in but now i can not get connectivity that way. Do you have a suggestion of how to obtain contact without stripping the wire? Another new thing once the new handle went on i am getting the light on the right side top and center lighting up. It does not stay fully lit rather it it strobes with different intensities. I believe it is the interlock override light. I am not sure what this all means, i was hoping you could help.
Hi, Cat have a 7x1710 probe group that inserts in the rear of the connector and are a must for troubleshooting in my opinion Have you verified you are getting 8 Volt supply to roller Mark
7X-1710 Probe Group. An absolute essential for testing components such as these. HeavyEquipmentForums
These might be a budget minded alternative: https://www.amazon.com/Electronic-Specialties-616-Spoon-Probes/dp/B07Q2MZSYH
When I posted above I almost typed "other alternatives may be available"........
yes that alternative would have been 55 dollars cheaper. either way i have the cat ones now. I will do those test and update tomorrow
I have a set of the cheap probes but the outer sheath is stiffer than the cat ones and the probes bend too easily for my liking I prefer the cat ones Mark
ok so i am very confused. I checked for 8 volts and had it (7.96v to be exact). when i went from pin 2-3 on duty cycle sometimes i would get a reading and sometimes not. when i did get a reading i would get 50% at doing nothing and then press up 20% and press down 79%. However when i would release the brake if i rolled up it would work sometimes and other times not. when i pressed down it never worked. at all these time the interlock warning lock was either lit or flashing. What does this mean and what should i do now? mind you it has a new RH joystick i installed and received from CAT.
Hi Craig, The 20% to 80% is what you should be getting ,however I don't understand why the duty cycle does not change when you release the park brake, unless there is some issue with the wiring .Have you checked the harness from the joystick to the ECM? The output from the joystick is only a proportional signal to the ECM which then controls the functions. As stated earlier the Aux ECM has been known to be problematic Cat ET is probably your best bet at this time here is a fault light chart that may help
I have a IDEAL 61-340 multimeter. I am wondering if it does not have the ability to read DC Duty Cycle. Reading through the manuel it appears that it can only read AC duty cycle. This may be why i am having such a issue getting a read. or should i say a consistent read
I just threw a different multimeter on it and turned the engine on with the parking brake on and rolling it forward i got about 20% always then not rolling it i got 50% and rolling it downward it went to zero every-time. Does this make any more sense?
No, 20% rolled forward is good,50% not moving thumb wheel is good but rolled backwoods should be about 80%sozero is definitely not good I am wondering out loud if you have a faulty joystick did you repair or replace the joystick or roller As for the multimeter. Years ago I bought a snap on multimeter, cant remember the model but it would only measure duty cycle at below 200 hz Can you supply an 8volt supply to the roller and check off the machine to confirm operation Small power supply are quite cheap and it is how I confirm sensor operation be it digital or analogue Mark
Yes I can do that as well as I am going to get my hands on another multimeter that is pretty new and see if results change. The joystick was new from cat bet I could bring it there as well and they would test it. Before that let me get a newer meter on it.
it may be a bit off the wall and we all know lightning doesn't strike twice in the same place, but check out this guy whose 299D wouldn't move. He put a new joystick on it and the problem was the same. Traced to a pin in a connector not making proper contact. Your attention is drawn to post #118 on Page 6. Just worth checking. HeavyEquipmentForums
It is worth trying, what makes things more difficult is that just before this issue started to happen cat had it replacing the hydraulic motors. I bet they had all sorts of connectors apart. Is the "J1" connector they are talking about the one one for the right joystick?
Hi Craig, J1 is one of the connectors on the ECM I am still not understanding why you are not able to measure the duty cycle of that joystick roller if you have a 8volt supply that is stable while operating the roller switch you should be able to measure the varying out put at the connector with the spoons placed into the back of the connector if you cant get that signal, it is a waste of time going any further, which is why I asked you to check off machine to verify that the replacement joystick is OK you can physically leave the joystick in the machine just remove the signal wire from the connector and test as before Just a thought. grab some spare connector pins and check for fit in the connector to make sure that any testing work has not enlarged the connectors and is making poor contact. You should feel a slight drag as the pins are paced into the connector Mark
Craig, if you don't have an Electrical Schematic for your machine feel free to PM me with the Serial Number and your email address. I can send one to you. If nothing else it will give you a handle on the expressions like "connector J1" and such, and show you where they are located.
It ended up being the aux. ecm. One part of it went and the old one on the bottom that was hidden had a hole in it.