D6N Codes — Dozers

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.

Nige said: 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. Click to expand... I will check this out. I appreciate it!

paulstrozier84 said: I will check this out. I appreciate it! Click to expand... I am using the screen as I do not have diag tools.

paulstrozier84 said: I am using the screen as I do not have diag tools. Click to expand... 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.

Nige said: 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. View attachment 364529 Click to expand... Yes they are all three active.

Nige said: 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. Click to expand... +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.

paulstrozier84 said: Yes they are all three active. Click to expand... 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

paulstrozier84 said: i went through the test today, and no luck. Click to expand... 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. paulstrozier84 said: Because it is not moving at all Click to expand... 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.

paulstrozier84 said: I do know the transmission fluid is clean and clear. as well as the filters changed every thousand hours. Click to expand... 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. paulstrozier84 said: we Discovered that the transmission has zero hydraulic pressure. Click to expand... 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

paulstrozier84 said: i have a 1000psi gauge and i will hook a smaller gauge to see if there is any pressure. Click to expand... 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.