I have been having an intermittent issue with machine, not cranking or starting. After a couple of days of machine being shut off, it starts right up no problem and I had the Cat technician do a computer diagnostic, and all that showed was abnormality in camshaft sensor, which I have Concluded has nothing to do with the no crank issue because it will crank with the sensor disconnected. My battery has been charged and it is a good battery. I have checked every wiring connection that I can find and fuses and relays. What have I not thought of? It acts like a self resetting circuit breaker. Would there be such a thing in the ECM? And why does it take so long to reset if that is the case?
Not sure if you have done voltage drop testing of all the positive cables and grounds. Need to start at batteries and end at starter. Something is no good in between. Tell us how you tested these cables. Simon C
Hi, what engine is in there? I’ve seen lots of ecm failures. Get cat et hooked up and download a product status report. Save as html so we can view it. When you download the status report it will show us everything that isn’t active. Go after the basics powers and grounds, but also hold it cranking and check for voltage at the starter solenoid.
Yes the ecm has capacitors and it can heat up and fail. Later on cools down and starts up fine. Seen it lots of times. Also swap around relays. Need to download product status report with cat et (press f6)
That only works for those who have ET on their computer. Better to save it in pdf so that everyone can read it. To the OP. Post a Serial Number so that the appropriate electrical schematic can be located.
Hmmmm I thought html can be opened by anyone using a web browser but ok. The serial number and all the goodies will be in the PSR.
The standard PSR is saved on the laptop as an xml file. Unless the machine trying to open it has ET loaded that file will not open. There is an ET PSR training video, available somewhere on YT, that instructs the user to save a pdf copy if the PSR is to be sent to a person who does not have ET installed on their PC. We used to download all our PSRs as pdf files because protocol dictated that a copy of both the before & after repair PSR was to be despatched to the customer along with the Service Report. Most dealers seem to do that.
Cool. I still work for a dealer and we always save it this way. Im using my phone so pdf should be fine.
I have a 2015 3.3 Kubota
Basically doesn't mean a lot. Please post a machine Serial Number so that we can identify the appropriate electrical schematic.
Ser#my201829
I connected scanner today and it doesn’t seem to be connecting with the engine ecm
Check your inbox for an electrical schematic I assume it is an aftermarket scanner, not Cat ET.? Can it read Diagnostic Codes.?
It is aftermarket but with cat ET program I had it connected last week and it showed engine ecm so not sure why it doesn’t show now. Ecm kaput?
I wouldn't like to condemn a very expensive ECM (maybe $4k) on the basis of a report from an aftermarket scan tool. Is there any possibility that you can get ET hooked up to it and have whoever does that generate a Product Status Report in Adobe pdf format.? It's an easy task once ET is hooked up. With that document the dog might just be able to see the rabbit. If ET does not see the engine ECM then it should show various Diagnostic Codes for communications failure between that ECM and the other electronic modules on the machine.
What year machine? Did you try to jump start the starter at the engine? You can eliminate a lot of possible issues if it will crank over at the starter.
I know what you are saying, it’s the crack version of cat et on a laptop. Still try to hook up and press f6.
I think so. But to get concrete evidence, it would be nice the see the product status report. It will show basically a tattle tell of everything that has happened with your machine. I’m hoping to see some codes pointing directly to the ecm. If you need cat ET, you can get the crack version for $100 and use the cat comm adapter or aftermarket.
I did try jumping at the starter solenoid and starter relay by the battery and both cranked the engine but will not start
Does the check engine light usually cycle on and go off after a second or so after you turn the key on? Not all machines are alike, but that will tell you if the ECM is getting power. Also, a good guess would be your crank position sensor is on its way out. It will not fire if it has a bad crank sensor.
Check engine light doesn’t come on at start up. But when machine decides to go it’s just fine, until that happens it doesn’t crank or start, display works and shows fuel,voltage,temperature etc. and blower is working. Relays click but no go. Wiring schematic showing 5 + wires to ECM I presume they are 12v but haven’t been back to machine since Friday to test them now that I know what they are, I will go there tomorrow.
Assumption not required. There is a colour-coded grid in the bottom RH corner of Page 2 of the schematic. The colour a wire is drawn on the schematic indicates its function.
I didn't realize it didn't crank, either. If you didn't try this yet... When it does act up, turn the key on and trip the solenoid at the starter and see if it will start and run. It sounds like you possibly have a bad relay.
Well what do you know, I was so focused on tracing wires I didn’t even see this. Thank you for pointing it out. Working with phone only no computer available
One thing that might not be shown on the schematic but you might find on the machine. There might be a short braided ground cable from the Engine ECM to one of the mounting bolts (because the ECM is rubber-mounted). If it is there make sure the ring terminal is clean and the bolt is tight. The one in the bottom RH corner of the illustration below is not from your machine but wil give you the idea.
There are two CAN Datalinks to the Engine ECM. The two pairs of wires for the Datalinks are Y797/Y798 and F711/F712. It could well be that a wiring fault is the cause of no communication with the ECM. If you want to test their continuity here is what I suggest....... Unplug the J1 connector on the Engine ECM. Trace the wires away from the ECM to the first major harness connector (CONN 1.?) and unplug it. Make a jumper wire and jumper the two Datalink wires together at CONN 1. At the ECM connector jumper one of the wires to machine frame ground. Connect a fused 3A or 5A test light to batt+ then apply the probe to the other wire in the pair. If the test light glows brightly the wires then straight away you have confirmed both wires are good. Repeat the above ad infinitum with every branch of any harness containing Datalink wires working away from the engine ECM.
Tested under load, as Nige says will rule out a good wire with no load, but failing under load. Takes a bit of time, but cheaper than a parts cannon with same problem not ruled out. Just for your info a 1156 Bulb draws over 2 amps, some do draw more. That is what I built mine out of. Simon C
Btw, quote the ecm. My last one took 6 months to back order.
Good ideas for sure I give them a try tomorrow, many thanks guys I will let you know how it goes
Any ideas how to test the ecm, I am not able to find any faults with wiring, relays, connections or fuses
Using cat et, download the product status report. Normally, a dealer will have a test ecm. I didn’t, so when I was confident in my diag, I ordered the ecm. Everyone on this thread is here to help, but we need you to get this status report. Btw, the guy flashing the new ecm will need that info.
This is what I have
Press f6 Or go to the information tab, scroll down to product status report
But yeah I can see that the engine ecm is missing. Great sign. Not for the customer lol
If the Engine ECM is missing on that screen and there are no Diagnostic Codes for lack of communication with it then it would appear that the ECM is dead IMHO.
Hey guys I ended up replacing the ecm and that was obviously the problem, I am getting ready to send the defective ecm out for repair and wondering if anyone is familiar with g7 computer repair, or knows of a good repair service?