I need some help on this one. I got a Cat 312E and the monitor states irregular battery voltage. If I go into the service menu and look at the general status it says alternator not charging. As well as when hooked up with Cat ET, I have an active event code that says alternator not charging. Code E179, but the alternator is charging at 27.98 volts. This machine has brand new batteries and cables in it. As well as a brand new alternator. They had already been installed when I got called out for this machine. I have verified voltage at the alternator r terminals at the service meter. Getting 27.9 volts at the service meter. In the process of checking at the switch panel. And I think there is a Alternator R terminal at the gateway module. Which I believe is under the seat somewhere. (The diagram isn't real clear). But where does the screen read alternator charge voltage from? I have verified that both modules have between 27.5 volts and 28 volts with the status tool in Cat ET. Am I overlooking something? Any help would be appreciated. Thank yall!!!
Sorry I forgot to give yall the model and serial. Here it is. Cat 312E MJD00437
Check pin 19, 403 green wire in the 20 pin connector for the switch panel behind the left side console.
Right side console. Not sure what I was thinking.
I am heading to the machine now. I'll let you know what I come up with
Pin 19 (wire 403) on the 20 pin connector has 27.95 volts with the machine running. But what's odd is if I unplug that connector while the machine is running. The "irregular battery voltage " message on the monitor goes away. It still says "alternator not charging" on the status in the service menu.
Did you backprobe the connector and check the voltage with the connector hooked up? From the schematic, it looks as if the monitor receives its information from the datalink.
Test both connected and disconnected. 27.95 volts either way. Just to cover my basics I also test the 403 wire at connector 16 pin 4 going to what the schematic calls the "gateway world view module" I am assuming that is the product link module. I have 27.95 volts there as well
Really makes me wonder if the control panel has an issue. Here is what SIS says about the E179 event: With an engine speed of greater than 600 RPM, the alternator gauge on the control panel is reading zero. Use Cat ET to check for diagnostic codes related to the electrical generating system." Part number originally is 327-7538 which had an improvement to the soldering joints to prevent short circuits, later on down the road they updated the part number to 510-9643 As far as a control gp from cat goes, this one is pretty affordable.
Sent my one 314E to dealer for intermittent travel alarm and bucket coupler. A wire was damaged between above said panel and the computer behind the seat. Took them a little while to find it.
I went ahead and installed a new controller. It wasn't terribly expensive as far as cat parts are concerned. But still the same issue. I have traced the (403 wire) to all controllers. It has the same voltage while engine is running at all end points. I have got to be missing something. Any body else have any ideas?
Can you test alternator output using 5he AC voltage setting?
From my understanding, an alternator should put out less than .5 VAC with engine running. This one test at .0 vac.
Most multi meters will not test the output for ac due to the messed up wave shape and frequency. On a typical alternator you will have about a .4V dc ripple on the DC output around 600hz depending on RPMs. It is not uncommon to have one phase in the alternator open or a main diode fail and still the alternator will charge to the correct output voltage. The only obvious thing is a reduced output under high loads. On a test bench you often can hear a louder than normal electrical wining noise but you will not hear that over your engine noise. Using an oscilloscope you can easy-ally see the uneven pulse on the DC where one phase is not contributing. You said it had a new alternator so would be surprised if faulty. I also would be surprised if the control panel had the brains to Analise the output of the alternator, I would assume it was just looking for a voltage to infer whether charging or not. Hope this helps Cheers
I finally figured it out. Turned out that the alternator that was installed was not hooked up correctly. They had the r terminal wire hooked up to the D terminal on the alternator, it was supposed to be hooked up to the W terminal. Sometimes the most simple thing is the answer. I guess the monitor looks for the waveform of the alternator.
Thanks for the update. Also, nice job going back to the source. Like most electronics on equipment, the don’t give much info on how they compute “alternator charging” within the panel itself.