Hey guys, working on a 2008 cat 297c skid steer, serial number *cat0297cjgcp00416. The parking brake will only release until I move the left joystick to try and drive. I can move the boom in any function and its fine, but as soon as the track moves it kicks it back in to park and then the light won't turn off again. The boom won't function again until I hit the park brake switch, even tho the park brake light doesn't go out the second time, it does allow the boom to function again. I've tested all fuses, relays, and power going in and out of fuse box under cab. Swapped joysticks to no avail. I don't have access to a scanner, nor does it have the optional display to check codes. How should I go about diagnosing from here? How does the park brake solenoid work? Does it apply power or ground to operate? Also read somewhere that it takes 12 volts to release brake, then sends only 5 volts to keep it out of park. If that's true, then what part controls the voltage? The guy called cat and asked if he could bypass the park brake solenoid and the tech told him you could but he wasn't able to give him that info for obvious liability reasons. It's stuck in his way so if I could temporarily wire the solenoid to a separate switch just to be able to move it then that would be a huge help. But I'm not sure how the solenoid operates and don't want to send 12 volts to it when it needs 5 and fry something. I'm pretty mechanically inclined and have also done quite a bit of automotive wiring and testing with a multimeter, so I'm confident I could wire it properly if only I knew how the solenoid functions. Any and all help would be greatly appreciated! I've read quite a bit on these forums and Nige seems to be extremely competent and willing to help, was hoping to get his advice on where to go next. Thank you, Boz
It sounds as though the LH joystick is not getting the correct neutral signal. The position sensor is a PWM type powered by machine voltage. Do you have a multimeter capable of measuring duty cycle so that you can measure the sensor output.? 126 PK is Batt+ when the key is on, 203 BK is ground. I sent you the electrical schematic. Check your messages.
Thank you for your quick reply! Unfortunately I do not have a multimeter that fancy, just a plain jane $30 one from autozone. I'll check voltage to the joystick and continuity to ground.
Actually I just checked and it does have the duty cycle feature. What would the spec be? 0% in neutral and 100% at full drive?
Try the centred (neutral) position first. It should be very close to 50%. More than 1% off and I would say that is your problem. If it is significantly over/under 50% try to move the stick slowly so that the reading comes to 50%. How far do you have to move it.? Duty cycle should be around 5-10% moved all the way to one end of the range, 90-95% moved all the way to the other end, and bang on 50% in the centre.
Thank you very much for your helpful insight! I will perform the duty cycle tests today and post the results. Thank you, thank you, thank you!
So the old joystick was way bad....duty cycles random and all over the place. The new/used one tested at 51.5% in neutral. All the way to 84% full drive and 17% the other direction. Old one won't come out of park at all, new one will come out till I try to drive then kicks in automatically. Tried a rh joystick that tested at 50.5% in neutral and the same thing. It kicks back into park. So the only thing I can figure is that the joystick fixed it, but now the ecm needs calibrated to the new one? Or is that 1.5% enough to say that the joystick is bad? If so, what are my options in buying the cheapest software that allows calibration and code clearing?
So the old joystick was way bad....duty cycles random and all over the place. The new/used one tested at 51.5% in neutral. All the way to 84% full drive and 17% the other direction. Old one won't come out of park at all, new one will come out till I try to drive then kicks in automatically. Tried a rh joystick that tested at 50.5% in neutral and the same thing. It kicks back into park. So the only thing I can figure is that the joystick fixed it, but now the ecm needs calibrated to the new one? Or is that 1.5% enough to say that the joystick is bad? If so, what are my options in buying the cheapest software that allows calibration and code clearing?
AFAIK joysticks are plug & play and do not require calibration. I need to check on that though, maybe someone else can comment.?
The owner swears he had swapped joysticks once before because of slow response but from what little I had read I thought they needed calibrated? Those posts mightve been referring to the 297d machines tho. The old joystick was definitely bad, as it wouldn't come out of park at all, and duty cycles were way off....just contacted a Stowers mechanic to see about calibration and he said he didn't think they needed calibrated either and mentioned something about a speed sensor possibly locking it down, and that it was a common problem on the D series machines. I guess I'm going to go down that rabbit hole and try to see what I can see about testing speed sensors/speed sensor wiring. Is there any other parts or pieces that could possibly cause this that you could point me in the direction on testing? Thank you
A thought just struck me. Please post a photo of your RH instrument panel. There might be a way to access Diagnostic Codes via that panel.
Best I could do as the cab is up and the shocks are wore out so I need another hand to raise and lower it lol.
That would be a huge help as I don't know exactly what he's done to try and fix it before he contacted me. Right now I'm in the process of testing the speed sensors. Speed sensor wiring is good.
Just checked an older Product Status Report from another C model. Looks like there is a calibration... Your machine was shipped from factory without any display option (literally a blanking plate installed over the hole). One could've been installed later. I'd get someone out there with Cat ET software, calibrate the joysticks and check for codes. That's about 20 mins of work with a slow laptop like mine. You don't need a dealer either. Alternatively if you have anything other than a blanking plate for a display, please post a picture of it as Nige suggested.
In that case a calibration ought to be the next move.
I agree Nige...problem is convincing him to spend the money. He swears up and down he changed joysticks once before with no issues but everything I had read before this thread said they needed calibrated. But I highly doubt that 2 separate items failed simultaneously on the machine and I know for a fact thru testing that the joystick was bad. Especially because with the old joystick it would only come out of park for a split second and only after disconnecting battery which effectively reset the ecm. Now it comes out and stays out until you try and drive, then kicks back in....Can you help me convince him that joystick calibration is the problem? Lol Thank you both very much for taking the time to help me as much as you have!
I would politely say it was his decision to buy a a machine without diagnostic capabilities (ie the monitor screen). You need ET software to efficiently diagnose anything without that screen otherwise you're just chasing your tail. Also, when you change a component, and there's a calibration available for that component, it's standard practice to run the cal. Without that the repair isn't complete. Who's to say the last joystick(s) he swapped out weren't just out of calibration? Who's also to say there's not something else going on as well as the joysticks? You need to see logged codes/events. You need to see what the drive motor speed sensors are reading while driving the machine. There's 4 of them. Imagine doing that with multimeters. With ET that'll take 20 seconds.
If I could Like the above post more than once I would..........
I couldn't agree more. And I think I've finally got him to understand that it's going to need calibrated, let alone at least knowing the codes I can see any issues it may have that he may not even be aware of yet. He's unaware of how necessary modern day software is when diagnosing. I think I got him to understand how necessary it is whenever I told him that this could've been fixed in a day if I had access to the software. Thanks again for all of your help and I will post the results.
The joystick was the only culprit, ans it now works without calibration. He had failed to tell me that he had modified two of the drive solenoids thinking it was the park solenoid a she got the wrong information from someone. I'm sure joystick calibration would help the sensitivity and make it smoother to operate, but its not necessary just to get the machine functioning. The duty cycles tested from 49% to 51.5% on 3 separate joystick sensors, and they all allowed it to come out of park. One was 47% and that was too far off to allow it to stay out of park. Thank you all so very much for the help!