I have a 143h missing forward 34and 8 reverse 3and6. It all revolves around clutch5 witch is solenoid 7. Iv got a code 647-6 that flashes on ET 100 time every 5 seconds. Iv checked coils wiring and every thing in between. Are ecm a common problem on these machines.
Can you post serial number for machine please?
Please post a Serial Number. There are Serial Number breaks in both APN & 1AL prefixes. EDIT: ahart was posting at the same time I was....... Have you tried switching the complete solenoid valve (not just the coil) to another location on the control valve to see if the problem moves with the valve or stays in the same location. ECMs are not a common problem. Depending on how may hours the machine has on it you could have a "tired" harness on the transmission control. Long-term heat adversely affects them.
Will add that if you have a current above Normal (short to ground) code active, a good test of the ECM is to see if the code will change to a current below normal (open circuit) If a true open circuit is created at the ECM and the code stays active as a current above normal, typically that would indicate an ECM failure.
Al00505 yes I have swapped the hole valve assembly’s. No change.
Please see my last post and report findings. Before you can condemn an ECM, you need to verify whether it’s responding correctly to changes made.
When I unplug solenoid 7 the above normal code goes away and the open circuit code comes up
You mean 1AL00505 I assume.? So when you unplug the solenoid you go from Code 647-6 to 647-5.? If so that would indicate the problem is in the circuit, not the in ECM. My favourite is still the transmission control valve harness. How many hours are on the machine.? I'll bet the harness is still original and probably over 20 years old. (1AL00505 built Feb 1998.)
I have Also run wire from ecm to coil 7. bypassing harness. And still same thing.
Have you checked for erratic signals from the transmission shifter switch to the ECM.?
Yes didn’t find anything out of the ordinary. And ET shows gear selection from shifter to be right but actual gear kicks out right after put in gear.
Only when you select 3/4/8F & 3/6R I take it.?
Yes sir
Don't you mean 2 wires.? Solenoid power AND solenoid ground.? Just for sh1ts & giggles try it with a bypass wire from the ECM to the solenoid for power and ground the other wire from the solenoid to frame ground instead of back to the ECM.
I didn’t run ground back to the ecm 3 others solenoids share that wire and the other 3 are working fine. I will try the solenoids ground to frame ground tomorrow.
I never asked if you had the electrical schematic although it sounds as though you do. If you don't you're welcome to a copy, just ask..
I agree. The schematic shows 2 ground wires numbered 921-WH, one for solenoids 1/2/3/8 and the other for solenoids 4 thru 7. A thought. The two solenoid ground wires are both shown as being spliced inside the transmission control valve harness as shown below. Is there any chnace that the splice in 921-WH from #7 solenoid return (arrowed) is showing continuity on a meter but is not up to the job of carrying the current necessary to operate the solenoid and is breaking down under load.?
It sure could be. Would that throw a currant above normal code ?
From what I know I think it's a distinct possibility. The thing is the 4 return wires are not common for their full length. Each of them is dependent to some extent on that splice somewhere in the harness, and I have no idea exactly where it is located. I'd like to hear an opinion from @ahart EDIT: That was also the reason for my earlier question regarding how many total hours were on the machine and whether or not the control valve wiring harness was still original. FWIW all our transmission overhaul kits contained a new wiring harness for the control valve.
11267hr they had the motor out about 8000 hours they said they did All harnesses in rear of machine.
If the transmission control valve harness was replaced at that time then it should still be nice and soft and relatively flexible. Worth a close look anyway. If it has the appearance of being hard and with crusty insulation draw your own conclusions whether it was replaced or not. That harness suffers a lot from heat and is usually works most of its life soaked in oil.
I went through the same thought process of the 921 wire being to blame between the splice and the solenoid, had it typed out and everything and bailed at the last minute because I decided that the only way it could affect only solenoid 7 was if the wire was broken between the solenoid and the splice which would be showing an open circuit. I’m just not sure if any situation on that side of the solenoid could trigger a current above normal code.
Part of my brain wants to say that it is possible if there’s high resistance on the 921 wire between the solenoid and the splice, that could cause a current above normal only in the solenoid 7 circuit due to it being a parallel circuit and the resistance on that particular leg only would have a relatively low effect on the total circuit resistance therefore the other solenoids would not be affected. It is also possible that this is a flawed theory, I’m open to correction.
I agree. Put simply I try to look at everything that it could possibly be and test for it before condemning the ECM, and I’ve seen enough issues with that control valve harness before to make me want to test it thoroughly before moving on. The power for the solenoids comes from the driver circuits in the ECM so it’s always possible that one of them is fried. The thing I can’t get past is the Code change from -6 to -5 if you disconnect the solenoid which suggests the ECM is working correctly.
I agree 100%, even if I couldn’t prove beyond a reasonable doubt that the harness was bad, I’d still probably change it before I threw an ECM at it. I wouldn’t hesitate to put a known good ECM on it for testing if the option were available, but it likely isn’t or would probably have already been tried.
Bang on. If I had any doubt whatsoever I’d throw a new harness on it before replacing the ECM.
Ah, the benefits of working with a fleet of equipment…..
I wish I had another ecm to try. I would have already. This is just one of them ass whoppers. So from here would y’all just throw a harness in it and see what happens.
I think that would be my move, yes.
Agreed. A harness probably costs maybe $150 vs $2000+ for an ECM. I'd go for a harness first as well. At the end of the day if a harness fixes the problem you're a hero versus a zero if the customer spends $2k+ for an ECM that DOESN'T fix the problem.
So I was way out on my prices but not so far on the relation between them. Harness a hair under $500, a new ECM $5k. The new ECM would also need to be flashed with the appropriate software for which the dealer Service Dept would problaby charge for since it was the Parts Dept who sold it to the customer and not them.
Ok is there 2 separate harnesses for transmission control? There is one that runs from the ecm to the back of machine and the one that runs from that harness down to each solenoid. Im having a hard time finding part numbers for them.
I guess what I’m trying to ask is if I get the transmission control harness from cat is it just the little spider harness at the solenoids? Or is it the hole harness from the ecm to the back of the machine?
The transmission control valve harness, the short one with the internal splices that we were talking about above, is a 147-1771 for your machine S/N 1AL00505. That's the one that generally gives all the problems. An easy way to get harness Part Numbers is this.... Look back at that snip I posted on the previous page. Above the 10-pin harness connector CONN 4 and slightly to the left is the letter "N", slightly to the right is the letter "F". These are the references for the two harnesses that meet at that connector. If you go to the ECM you'll find the harness plug at the other end of Line L46 from CONN 4 is also labelled "F". Go to Grid E-1, Page 2 of the electrical schematic and you'll find a Table with wiring harness letter identifiers and Part Numbers. Harness "F" (RH Frame - XMSN) is listed as 143-3433. Harness "N" (XMSN) is listed as 147-1771. Asking a dealer for the numbers above might actually get you newer numbers but when that electrical schematic was drawn up those were the correct harness Part Numbers.
See above. I assume that you do have access to an electrical schematic.?
Yes I do. Would you replace both harnesses N and F see what happen. If nothing changes replace ecm.
And I found the part numbers on the schematic. Thank you
I'd only replace harness N for a kickoff because that's the one with the splices in it. It's also the one that gets most of the heat and the oil contamination. The updated Part Number for harness N is 147-1771 that was installed starting with transmission S/N 4NY00458, about 100 Serial Numbers lower than the transmission in your machine. The difference between 137-1120 & 147-1771 is the steel "ladder rack" in the illustration. If the rack is on the transmission in your machine is still good then why not re-use that one and a few new cable ties plus a 137-1220 if it reduces the price.?
Here's the breakdown of the 147-1771, just for confirmation.
Yes harness is ordered should be here in the morning. I will let you know what happens.
Transmission harness did not fix the problem.
That's a bit of a bugger. Unless @ahart can think of a reason for replacing the harness "F" (143-3433) between the transmission and the ECM it appears as though the ECM is the culprit. As I said earlier it could be that the driver circuit for clutch #7 is failing but that is not what the -6 (connected) -5 (disconnected) Codes indicate. There is a 10R-4332 Reman ECM available for OEM P/N 172-9389. It will probably be somewhere around 50-60% of new price, maybe $2.5-3k range, if you want to take a punt on a Reman. Whichever option the replacement ECM will be a blank box and will require flashing with the appropriate powertrain software for the machine Serial Number. I'm guessing that the dealer Parts Dept will have to involve the Service Dept to do that for them.
I’ll admit, the data on this one is very conflicting. But if we’re at an ECM and we are confident in the data that we’ve got, then we have little choice but to go that route.
My thoughts too. The -6/-5 Diagnostic Cdoe data conflicts with an ECM failure but there really appears to be nothing else left. IMO replacing the 143-3433 Harness would likely be throwing good money after bad.
Just to give a little more info I was able to get in it and run it today. When up shifting first second then third as soon as it hits third it will kick in gear for 1 second then the transmission light on the dash will go to flashing and it kicks out. I can shift straight to 3rd and it will kick in and stay in one time out of 6-7 shift.
So if I understand you correctly if you start in 1F and shift to 2F then 3F it takes 3F but then every time it kicks out after 1 second with the Transmission Fault light and a Code. If you select 3F directly and take off it faults 6 times out of 7 but the one time it does hold 3F OK have you tried shifting up to 4F.? If so what happens.?
It does this same thing in every gear that uses the number 7 solenoid. When I get it locked in 3 as soon as I shift to 4 it codes out.
New ECM and she shifts just like she should.
Glad to hear that. Did you go the Reman or new route.?
Customer wanted To go reman. Thank y’all for the help.
Thanks for the follow up. That one is surely going to get filed away for future reference because playing strictly by the diagnnostics book the FMI change from -6 to -5 when the #7 solenoid was disconnected indicated that the ECM was not the cause of the problem.
The guy and cat that did the ecm flash said he could see the code flashing. I guess in his break out harness. He said it was a pain to copy old config with it doing that.
Thanks for the update, definitely one of those I would have been nervous about putting an ECM on.
I'll second that, especially based on the test results. And having been on the wrong end of more than one transmission control valve harness failure over the years I was reasonably certain the harness was also the problem in this case. I know ECMs do fail. Well obviously - this one did........... But it's such a rare occurence these days unless someone's being doing something really stupid such as welding on one end of a machine with the ground cable attached to the other end, or trying to jump start a 24v machine from something 12v. There's a reason why the last option listed for the possible cause of failure in any Diagnostic Code troubleshooting procedure generally states "The ECM has failed. This is unlikely." Often the procedure will tell you to repeat all the steps again if nothing else shows up, just because an ECM failure is such a remote possibility.
Agreed, I always assume that I must have missed something if I get down to the ECM being the problem. So we go through it all again, and again. Also on copying the old configuration files from old ECM to new ECM, cat doesn’t typically recommend using that feature, not so much on a failed driver as on a corrupt file, they say it’s likely that the old file could corrupt the new ECM. Was talking to the TC at cat a few weeks ago and now they’re recommending never downloading software from SIS over WiFi, they want it done over hardline only for the same reasons. Sure makes it hard on field service.
Cat needs to get their s*** together and they sure do love to come up with a billion reasons of “oh why you shouldn’t!!!!” To cover their B.S. We have to download files over WiFi. Never an issue. And getting their copies of the original configuration files can be spotty. We copy the configuration and PSRs of every machine we PDI and attach it to the first work order so that helps some.
Think yourself lucky you're doing it today. Years ago the only way was to download flash files over an ethernet connection, store them on a floppy disk and take them to the job site with you. If you got really stuck you'd call someone back at the branch and have them download a file and email it to you as an attachment. The only challenge left at that point was to find someone you could hook up to an ethernet cable and download the file. I can recall many times in the filed gettng factory passwords over the phone with someone back in the office who could hook up to the system. Happy daze .............
Ok in back with more issues with the same machine. Operator lost 5678 forward and 456 reverse. Already have new solenoids and a new harness and reman ecm. No codes this time. I’m getting 1.7 volts to the D solenoid bottom out side but never getting 24. Check at pin 11 at ECM and still just getting 1.7volts. When I unplug it I get a code. When hooked to ET it shows the shifter abs gear to both be in the right gear but won’t move.
I'd suggest two things. 1. First re-flash the software into the ECM. I've seen cases of "missing" bits of software that caused ECM's to act screwy before now. Only two things control the output of the 24v on whatever pair of pins it is for each solenoid; the ECM hardware/internal wiring, and the installed software. 2. If the previous step doesn't fix the problem I think you're in for another ECM. Seeing as it only laste a month it's known as "infant mortality". It happens occasionally. I'd like to hear what @ahart thinks........
Is the bottom outs side solenoid the right solenoid for the gears missing? Dealing with these solenoids is kinda a pain. Some say solenoid d or 4 but it run clutch 8 I think and the wiring diagrams are weird too.
Solenoid D controlling clutch 8 would be the common one for the gears you’re missing, unfortunately, reman ECMs can be like this on occasion. It’s worse when it happens after fighting and fixing another problem concerning the same ECM.
Maybe this might help. Here are both Test Point Diagrams and the list of clutches. IIRC Clutch #8 solenoid is the inside one on the bottom, closest to the transmission.
So Nige this diagram is not right.
You're right. My mistake, Clutch 8 solenoid is the outside solenoid of the bottom pair.
Found this. Clutch Numbers for the solenoids and presure test point letters all in one place.