I have a D6N Serial#mg501650. Got called out today because it quit moving and popped codes 247-9, 673-2, and 585-2. I've checked all the grounds and canon plugs i can find. I thought i had an issue with the transmission internal harness as it would lose resistance when wiggled but that got swapped today with no change. It does not throw the speed sensor codes until you attempt to put it in gear. Ive Ohmed everything i can find on the Powertrain ECM to the speed sensors with no issues found. Is there anything else it can be? We did recently have the cab off to put an engine in it if that helps any. I did check and have 59 ohms between my can buses at the powertrain ECM. I do have an electrical schematic for it. Please Help! Thank You!
Are all three of those Codes Active.? How are you reading them, from the Monitor Panel or do you have diagnostic software.? 585-2 is the transmission output speed sensor #1 - data erratic, intermittent, or incorrect. 673-2 is the for converter output speed sensor - same as above. I would suggest that you troubleshoot both those faults first. See the attachment. It is the same test for both sensors. You will need to use the procedure in conjunction with the machine electrical schematic. UENR7720 covers MG5 machines with S/Nos above 1240. One thing I will suggest is not to place 100% reliance on measuring the resistance of a wire (as per Steps 2 & 3 in the procedure) to determine its condition. A better test is to jumper one end of the wire to machine frame ground and apply batt+ via a fused 5A test light to the other end. Any wire that will pass 5A without going pop should be good.
I will check this out. I appreciate it!
I am using the screen as I do not have diag tools.
That will work just as well. Can you confirm all three Codes are Active. In other words there is the "X" in the RH column alongside the Code in the window of the Monitor Panel.
Yes they are all three active.
+1 on load testing the circuits instead of using a resistance measurement. I've tracked down a lot of corroded circuits that had perfect continuity.
Just checking.
i went through the test today, and no luck. Because it is not moving at all, do we think the speed sensor codes are throwing? It wont even turn just tries but acts like the transmission is locked down. Ive double checked everything on the brake side i can find as well. Is there anything right off that can just lock it down like that? It happened out of nowhere. They've been using it for about a month since we last did work on it. It has about 7200 HRS
Can you elaborate please.? Did every step of the speed sensor tests come back negative for both sensors.? That's not exactly logical if there is an Active Code, because the fact that there is indicates a problem of some sort. Can you confirm exactly what the machine is doing or not doing as the case may be. Does the engine start normally and respond to the throttle.? In other words can you get High Idle RPM out of it.? Does the parking brake indicator light go out when you move the park brake switch to the OFF position.? When any transmission gear in FWD or REV is selected does the correct indicator show on the Monitor Panel.
everything tested out normal to the sensors. Everything was in spec. The machine will not move. It starts, idles. full throttles with no issues. The park brake light does goes out and the solenoid does magnetize to dump it. when put in gear it does show the correct FWD and REV on the screen. Ive tried all the clutches 1-4 in FWD and REV. and when trying to turn it. It whines and wont turn. Just like the transmission is stuck.
OK, so on the basis of that there is nothing wrong with the data link to the Engine ECM. A comms fault on the CAN network to that ECM would not allow the engine to start. The only other thing I can think of is to dig a little deeper into the Active 247-9 Diagnostic Code with regard to the Powertrain and Implement ECMs. See the attachment. If that throws up nothing (and I have no idea why it should when there is an Active 247-9 kicking about but then again I thought the same about the speed sensor Codes) then IMHO it's time to break out the gauges and start testing pressures in the powertrain, starting with the pump.
While I think about it start by testing the powers and grounds to both the Powertrain and Implement ECMs. You will find multiple switched and unswitched powers on both of them in addition to multiple grounds.
I did check all my power and grounds to the power train ECM. But I did not on my implement ECM. I’ve got someone coming with a bit more experience than me to help so hopefully we’ll figure something out.
With the help of the guy. we Discovered that the transmission has zero hydraulic pressure. im not sure what this could be. He chased down the code to either the Implement or Powertrain ECM not communicating with each other. But we will have to figure out the pressure issue first. Is there anything that could all of sudden give up? or break? I do know the transmission fluid is clean and clear. as well as the filters changed every thousand hours. The driveshaft that comes from the torque converter to the transmission does spin as i noticed when i had the floor out.
No chance that it has had a hose failure and dumped all the oil.? You mention filters being changed but has the pump suction screen/magnet assembly ever been removed and cleaned.? Access is not simple as it involves removing the bottom guard under the transmission. See the attached for measuring the transmission relief valve pressure. Is the circled test point in the illustration below where the zero pressure was measured.? Was the pressure measured actually zero or just a very low pressure.? A lot depends on the maximum pressure reading of the gauge that was used to do the measurements. If the gauge used for testing was say 1000 or 2000psi max and indicated "no pressure" has anyone put a 50psi gauge on it to look for even the most minimal pressure when the engine is running.? Need to go back to the moment when the machine quit. What exactly was the operator doing.? Moving along normally and the drive just stopped, dozing, changing direction, etc.?
Any developments in this issue.?
sorry we had towed it back here to the shop. everything on the powertrain side has no pressure. Do you have a troubleshooting guide for the powertrain pump? We are fixing to dig into it a little more and see if we can figure everything out.
operator was just pushing a pile and the machine just stopped. He said There was no noise. i have a 1000psi gauge and i will hook a smaller gauge to see if there is any pressure. Even the test ports on the right hand fender have no pressure
Here’s what I suggest. 1. Connect a 50psi gauge to the port I marked above. Start the engine and let it idle. If you have absolutely zero pressure on that gauge go to the next step. If you have any pressure at all, revert back here for further suggestions. 2. If there is absolutely zero pressure then remove the quick coupler from the same test point and start the engine at idle. Do you get any oil at all out of it.? It goes without saying that you need to do this step VERY CAREFULLY. Oil under pressure could seriously injure somebody.
It might be a stupid question but are you absolutely sure there is oil visible on the transmission dipstick.?
All I had was a 250psi gauge and I had nothing. This is what the back of my dozer looks like. I took a pick and mashed the port in. No oil at all ran out.
Removing that fitting reminds me how we use to bleed the pumps on underground machines on start up or it they ran out of oil. We use to put 2 psi with a rag over the fill hole to help push the oil to the pump. It is either air locked or something is very wrong inside. In post #16 it was said to remove suction screen from bottom, was it ever done or did I miss something? Simon C
No I did not. Until now I believed the issue was electrical. But now that I’m tearing deeper in it. I’m gonna pull it out.
I think removing the screen is probably the next logical move. As mentioned earlier it will require the bottom guard under the transmission/torque converter removed (and the powertrain oil drained) in order to access it - HOWEVER........... 1. Did you confirm 100% certain that there is oil in the transmission.? 2. I would still suggest that you remove the test point completely and at least bump the engine over on the starter to conclusively prove there is no oil flow whatsoever at that point. If that is indeed the case, read on........ The fact that there is no oil flow at the pump pressure test point indicates (to me at least) that it is a problem upstream (pump side) as opposed to a problem downstream (brake/transmission side). This is because if it was a problem with the priority valve causing a loss of oil to the transmission there would still be oil pressure at that test point but it would be going to the brake system. To me it boils down now to two possibilities. 1. No oil is reaching the pump - could be a plugged suction screen or a collapsed pump suction line but if that is the case why are there no cavitation noises coming from the pump.? At least there has been no mention up to now of such noises. 2. For some reason the transmission pump is not turning or has suffered an internal hernia. that's going to need the pump removed to diagnose why.
Yes I know it’s full of oil. And there is no noises. It is quiet as a mouse. I’m getting it ready to pull the screen now so I’ll update when I can
If you haven't removed the bottom guards already see the attached. Budget on everything being at least 50% heavier than stated, simply because of the amount of dirt that will be in them.
Looking at that photo is there another test point hidden behind the blue hose & wiring.? I thought that I could see the edge of a rubber cover in the shot. If it is actually a test point then that’s the one you need to be on.
That’s the one I used. And it’s got nothing. Screen is out. I mean it’s got some but nothing like a major failure I believe.
If you have never previously removed that screen during the time you have owned the tractor then what’s there and on the magnets is just normal wear. Time to pull the pump I think.
It is the first time it’s been out for me but I’m gonna assume the pump is the one with the suction hose to the transmission?
I do believe I have found the issue. No idea how the operator never heard this but oh well. Will hopefully update once parts arrive to repair this.
Is that the drive shaft for the transmission pump.? If it is I just won a $20 bet......!!!
Yes sir it sure is
Think you were correct about your hunch Nige earlier this morning.. That why I like to follow the tutorial. Simon C
Like always, follow the data.