Hello, My friend bought himself one of these Bobcat 753 mashines. He bought it on auction so any info about it's past is unknown. When turning the key, there is one long beep and 3 short ones. If pressing the green button "Operate loader", the seat bar LED and the traction LED turn on, but not lift & tilt valve. No flashing of any LEDs. I was reading somewhere that there are LEDs on joystick... I think this one doesn't have them. Can someone please help me? I have no service manual and the only company that fixes these things in my country is saying that the computer is fried. We bought a new one for 1200€ and still not working. There is aslo an error code 21-03 on the display...
The 21-03 error code is a "Glow Plug Output Error Off". What series machine do you have? Can you post the serial number?
Info plate: Compact skid steer model: 753 Product identification number: *516222165* Year of construction: 2001 Today I found service manual for 751, which also has this "interlock system" thing, and there it said that if the LED for lift & tilt is off then the control valve cannot be used. There are three possible reasons for this to happen in this manual: Number of LED diode flashes/Reason: 1 Control valve open circuit 2 Control valve shorted to battery + 3 Control valve shorted to ground I found this control valve… It has a coil, which has to have 10 ohm resistance, which it does. There is 5.7V on the connector for the solenoid valve, but only if you unplug it. If you unplug it, then the LED starts to flash once, which is correct - open circuit, also there are 4 beeps. When the connector is put back together, then there is no voltage on the pins. I am guessing the solenoid is ok. Don't know why there is no voltage on the coil when you turn the key on. This manual for Bobcat 751 is not good for diagnosing my 753. There is no mentioning of beep sounds, so I can't check what 3 beeps mean. Do you think that 21-03 error is causing this? I have read somewhere that this is a "Glow Plug Output Error Off", don't know how to fix it, don't know if it's related...
You mentioned that "There is 5.7V on the connector for the solenoid valve, but only if you unplug it...When the connector is put back together, then there is no voltage on the pins.", which connector are you referring to and how are you measuring the voltage when "the connector is put back together"? I am not doubting your troubleshooting thus far, only making sure I am looking at the correct "connector". Unfortunately I just finished replacing spools valves, springs, seats and all o-rings in my bucket control valve and won't have it back together and working until this weekend (at best). I do have a 753 dealer service manual and will do some looking for you tonight until I get mine back together and can then maybe assist you by getting you data from a working machine to compare your data with.
If you're getting beeps from the alarm then it's a G series machine, C and F series didn't have that alarm and the K series is later than 2001. Just to let you know how a G series is "supposed to work", if all things are working proper, when you power up the ignition you get one long beep from the alarm. That long beeps serves two purposes, 1) it's the main controller doing a self test, testing that things are working on power up, and 2) it tells you the alarm is working proper. After power up and after the long beep, anytime after that, if you ever hear three short beeps from the alarm that's the main controller seeing a fault and alerting you. Right then, don't do anything else, instead, at the moment you hear three short beeps, push and hold down the headlight button, this will bring up the active code(s) that caused the three beeps. Also, Bobcat machine do not "store codes" like automotive ECM's will do, Bobcat machines only work with current "active" faults/codes. Once you turn off the ignition it wipes clean. I doubt the glow plug fault is causing your problems with the BICS interlock, it would explain you getting three beeps immediately after the single long beep. Typically with faults with the BICS interlock, you should hear another three short beeps when you push the "push to operate" button. If that does happen, check you code(s) again after you hear those three short beeps.
hey First... The link to the manual, that I am using right now: https://www.usedloaderparts.com/wp-...14711001-and-above-sn-514911001-and-above.pdf The connector that I am referring to is on the "BRICS Hydraulic control valve". There is a magnetic coil on it, which (by the service manual) has to have voltage present, when the LED for lift & tilt is ON. The valve is mentioned in "BICS troubleshooting section" and it writes that if the LED is flashing an error, then this valve is the reason, but I've noticed that it doesn't flash an error, it just stays OFF and in the manual, there is no mentioning of the possibility for the LED to just stay OFF. Page 387 of the manual - Troubleshooting chart Page 66 of the manual - The BRICS control valve (the magnetic coil is seen in on the picture) I am measuring it betwen the metal of the machine(-) and betwen one of the two pins (Green wire). Black one is GND. I removed a bit of insulation on the green wire for "crocodile clip" to fit on it. Thanks for the info, I've newer sit in a working one, so this helps me a lot. I will repost when I get to the mashine. It is not at my home. Thank you all so far for helping me.
I had very similar problems with my 753G recently, it turned out the voltage was low coming from the fuse block under the seat there between your legs. The alloy connectors for the fuses were allowing some current to flow and voltages were all over the place. Once I bypassed the fuse block with inline fuses, I got full current flow and voltages to the solenoids to get everything to work, this could explain your voltage issues?? Cheers LOX
easiest thing to check is your battery connections, especially the ground. pull the cables and clean both the battery and cable ends then retry. probably 90% of the machines i see with an electrical problem it starts with battery connections.