I have a 2017 277D (SN FMT00869) that I've owned for about six months. I just use it around my property, so nothing commercial. It worked fine when I last used it a month ago, but when I restarted it the auxiliary hydraulics don't work. I have code 2204-3 (Auxiliary Lever #1 Position Sensor Voltage Above Normal). I've gone through the threads that mention this code ( HeavyEquipmentForums ) and have tried to check all of the things mentioned at HeavyEquipmentForums . Test 2 and Test 3 both passed. I tried Test 1, but couldn't get good data for the duty cycle. I don't have the official Cat back probes (7X-1710 Multimeter Probes) - is there something else that works for that? I tried with paper clips attached with alligator clips. I had one flash where the multimeter read 98%, but I don't know if that was a real reading or not - if it was, it suggests the sensor is dead. I've opened the joystick and don't see any wires with visible wear, and couldn't find any issues with any of the wiring harnesses or loose connections. My questions: 1. Any tips for getting the back probes to work for the duty cycle test? 2. If the duty cycle test confirms that the sensor isn't working, is there a way to fix it, or do I need a whole new joystick assembly ( https://parts.cat.com/en/ringpower/460-5342)? If you have any other tips or ideas, I'm open to them. I'm not a mechanic, and this is my first Cat, but have done a fair amount of work on other equipment (Bobcat) and I'm usually pretty good at basic repairs. I could take it into a shop, but they generally take a long time to get things fixed (usually at least a month), so I'd like to do it myself, if possible.
A lot of good information above. There may be a way to short-circuit the duty cycle test though. Please post a photo of the monitor panel in the top RH corner of the cab. There may be a way to see duty cycle without resorting to testing with a multimeter.
Here's the monitor
On that particular panel is it not possible to use the setting menu (extreme RH button directly underneath the gear symbol) to access operating parameters such as the joystick sensor output.?
This is all that I could find with joystick information.
The last 4 rows are the joystick position sensor duty cycle values. Move each joystick in one axis at a time and watch the percentage numbers move.....
The joystick position sensors all work fine in all directions. I don't see anything for the auxiliary position sensor, though.
Gotcha. Sorry I should have read your OP with a bit more care. I don’t think that there is any other way of measuring the signal from the thumbwheel roller without using spoons, although the bent paper clip trick also ought to work. The only other way I know is to knock up a breakout T-harness where you plug the probes of your multimeter directly into the branch.
I bought some spoon back probes. When I test across the green and white wires, I get 7.3v, but 0% (i.e., nothing) on duty cycle. Is the pin layout of my machine different than the PDF instructions? I tried all combinations of green (there are 3 green wires) and white (there is only one white) but no duty cycle.
The pin layout is the same as mentioned in the troubleshooting procedure. Pin #1 is Yellow #P769, Pin #2 is White P770, Pin #3 is Green P996. If you look closely on the back side of the connector the Pin Numbers are moulded into the plastic housing. Try this test as confirmation. Check the voltage between the Yellow and Green wires with the key ON. It should be 8.0 +/- 0.5v. Report your findings.
Yellow to white is 7.96v. Yellow to green is 0.6v. Green to white is 7.36v.
Therefore the thumbwheel roller power supply is good. That's the only two wires across which measuring voltage makes sense. It also means that you are testing on the correct wires. If the measured duty cycle signal across Pins 2 (White) & 3 (Green) does not deviate from 0% irrespective of whatever poisiton to which the thumbwheel is rolled, then the roller position sensor is foobarbed. Unfortunately that means a new joystick handle because the roller/sensor assembly is not available separately. See the attached parts listing.
Is there another set of wires I could test duty cycle for another sensor? I just want to make sure I can get some reading that isn't just 0%.
There certainly is. See below for an illustration of the 6-pin connector for the joystick position sensor signals (located somewhere fairly adjacent to the 12-pin in your photos) close to the bottom of the joystick. Check the duty cycle measurement between Pin #3 (E850 Brown) and Pin #2 (A285 Black), and Pin #5 (L804 White) and Pin #2, obviously with the key ON.
Just to confirm something. Which way is your RH joystick configured.? 1. Thumbwheel roller + trigger + 2 push buttons. 2. Thumbwheel roller + trigger only. Depending on which type you have the Part Number of the Handle Assembly will change.
Nige, you've been very helpful and I appreciate it. Thank you. Mine is roller plus trigger only. I tested the other two pin combinations. I did get voltage across them (so I had a good connection), but the duty cycle was always zero. I checked on the screen and the position sensors worked as expected with the full range of movement, but I couldn't get ever get any duty cycle to show up on the multimeter. I tried with a second multimeter and got the same result. I also checked the multimeter on an electric drill and it successfully measured duty cycle with that, so the multimeter is working. Before I buy the part, any other ideas to try to check the duty cycle with any of these components?
OK, so what I posted earlier is incorrect. The replacement RH handle with only a roller and a trigger is a 273-9103 rather than 273-9104. It might be a stupid question but I'll ask it anyway. Do you have you meter set to frequency (Hz) or duty cycle (%).? On most multimeters that I have come across with the capability to measure duty cycle you press the Hz button once and the display window will show an "Hz" icon. Press it a second time and the Hz icon will change to %. Below is how it works on my Fluke 87.
Mine is the same and I switched from HZ to %. Mine is a Klein MM450, for reference.
In that case I have no idea what's going on. Obviously the joystick position sensors are working because you can see the duty cycle changing on the display yet for some reason your two meters don't see it. Have you tried measuring duty cycle on the thumbwheel roller between the 996 Green wire for the signal and machine frame ground rather than the black wire on the 12-pin connector.?
I never figured out duty cycle with my multimeters, but I wonder if their ranges are such that they just couldn't recognize the ranges with the skid steer? I hadn't tried using a different ground, but tried to use the frame ground and got a slightly lower voltage, but no duty cycle. What I did do is get an oscilloscope and hook that up. When I tested the joystick position, the wave did change in size as would be expected (square waves as it switches between high and low voltage). When I checked the aux position sensor, there is no wave, just a constant voltage. This confirms that the position sensor is not working. Before paying $650 for a new handle to replace a single sensor, I'm going to take apart the current sensor and see if there's something obvious that can be fixed. At least, though, I've confirmed that the current sensor is indeed bad. I'm including the oscilloscope readings for the good and the bad circuit for reference in case anyone in the future has a similar problem. For the good sensor, as I change the position, the width of the higher voltage wave changes.
That's exactly what a PWM (Pulse Width Modulated) signal should look like. The voltage cycles between a low value and a high value, in this case between zero and +/-5v, only the width of the "ON" pulse changes between 10% duty cycle and 90% duty cycle.
An update for any future readers: I took apart the sensor as discussed in HeavyEquipmentForums and mine was a little dirty, but the magnet and springs were in great condition. I hooked up a bench power supply at 8v to the input wire and measured the output and always got slightly less than 8 volts back, no matter the position of the sensor or magnet. I'm pretty sure the problem is inside the sealed portion of the sensor (I didn't cut it open) and my best guess is that a short developed in there which is why I get nearly the same voltage back that I put in. $691 later, I have a new handle and it all works fine. I have to say I'm kind of appalled at paying nearly $700 to replace one sensor that breaks the entire auxiliary system of my skid steer, but that's the way things go.
I'm glad you got it fixed, and sorry that there is no cheaper fix to replace the sensor rather than a complete new handle. Back to the voltage subject again, for the benefit of anyone else who may come across this thread at a later date. Measuring output voltage from the thumbwheel sensor is a waste of time, as the output voltage varies between LO & HI values on a cyclic frequency as per the waveform I illustrated above. Either an oscilloscope or a multimeter set to measure duty cycle is the only way to satisfactorily measure the sensor output. Question: Did you try measuring the output of the replacement sensor using your multimeter and if so what were the results.?
I didn't measure the new sensor before I installed it, but I did measure the other joystick sensor that was working. This may be a function of my multimeters (both are in the $60 price range) and may also be why they struggled with duty cycle, but they report the average voltage. I hooked up both my oscilloscope and multimeter to the same working circuit (separately and together). The oscilloscope showed the highs and lows, just like in the image you shared and in the photo I shared, but the multimeter reported a voltage that was approximately the same as the average voltage (Vave) the oscilloscope reported. So when I moved the joystick, the voltage changed from something like 1v to 4v with the neutral position being around 2.5v. I know that the true voltage wasn't ever 2.5v (it was cycling between a Vmin of 0v and Vmax of 5v) but that's how the multimeter reported it. This also came up in the longer sensor thread ( HeavyEquipmentForums ) - my guess is that quiksilvr was also measuring an average voltage. Going back to the original code, it is "Auxiliary Lever #1 Position Sensor Voltage Above Normal". It doesn't say duty cycle above normal, but that the measured voltage is high. Now this could be simple naming conventions, or maybe the ECM reads the PWM output similar to how my multimeter reads the PWM output as a change in voltage, as opposed to a change in duty cycle, which is why it reports the error as high voltage? My takeaway is that for other people testing this code/sensor, if they can't measure the duty cycle, they might be able to measure the voltage and as they actuate the sensor see a change in voltage for a working sensor - not because the voltage is changing, but because that's how their multimeter is reporting it.
What it is referring to is the "pull up voltage" generated by the ECM on the signal wire. This voltage is a fault-finding device used to test the circuit when there is no PWM signal from the sensor driving the output, and throw up Diagnostic Codes such as 2204-3 (and 2204-4). The ECM is looking for the LO-HI voltages on the signal wire, not the duty cycle or frequency. It then compares them to stored default values and if they are more than a certain amount out of spec it throws up the DTC.
And the implication is that if the LO-HI voltages of the PWM waveform are off from specification then the duty cycle will also be similarly off despite the fact that the on-board machine diagnostics cannot measure it.