I have a 320L that is showing a high voltage code. It all started with the govenor control intermitantly working the backup switches always worked then only the backup controls worked. Next the batteries died twice took them out and charged and load tested they were fine now they have not died for a month. Now the battery light came on so I take the altornator to a local shop and they tell me everything is fine right on spec. Still have high voltage code and light on 28.7 volts. The throttle still deos not work and can't do anything with computer because of the code being active. I have mettered all wires replaced the switch on the dash with no luck. I have the books done all I can think of and all anyone else I know. Does anyone have any ideas I am hopeing it is not the computer but it is looking like that is all that is left. Also the A or U code that lights up in front of speed setting when you flip the manual govenor or pump control works intermitantly but the backup controls work just don't put the letter on the screen. Any help will be appreciated.
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320L High Voltage code
- Thread starter 06Pete
- Start date
I'd be starting at the large connector at the ECU... sounds like the connection might be corroded. What lights are on on the ECU? should be green only. Yellow indicates communication error to monitor panel. Red = ECU fault
What voltage do you have at the batteries when the machine is running? Is it 28.7 V? If so, the alternator is the culprit.
What voltage do you have at the batteries when the machine is running? Is it 28.7 V? If so, the alternator is the culprit.
The ecm light is green the connectors are clean the voltage is 28.7 at the batteries that is within the spec of 23.4 to 32 that the book calls for and right on what the alternator is spect at according to the local repair shop I carried it to. they said they checked two sorces and the regulator was set to cut off at 28.7 so rebuilding would not change a thing. Tommorow I am going to check all grounds as I talked with cat and that was the only sugestion before replacing the ecm. This ecm is not able to be tested for more than power on as I was told by cat I guess I will just throw $3200 at it and hope for the best. Unless anyone has any more ideas. Thanks for any help.
you're right - 28.7 is within spec for that alt.
Well, I just looked in the manual. 320L has no code specific to High Voltage.
The only code that would specifically show too high battery voltage is
"[Elec #18-1] Battery Voltage Is Abnormal (not within 23 to 32V). "
same code for high or low. I'd be looking for poor wiring and a cause of LOW voltage to the controller, not high.
A pair of 7X1710 probes in the power and ground pins of the controller will tell you what voltage the unit is actually getting.
Well, I just looked in the manual. 320L has no code specific to High Voltage.
The only code that would specifically show too high battery voltage is
"[Elec #18-1] Battery Voltage Is Abnormal (not within 23 to 32V). "
same code for high or low. I'd be looking for poor wiring and a cause of LOW voltage to the controller, not high.
A pair of 7X1710 probes in the power and ground pins of the controller will tell you what voltage the unit is actually getting.
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I have checked voltage and resistance through every circut that I can think might even be related to this problem. Everything keeps showing normal. I have pulled the cab apart and checked every ground from the cab to the ecm to the alternator. I guess at this point I can't think of anything else to check and am going to order a ecm and hope for the best. As far as the voltage code I guess we just assumed it was high because 28.7 seemed high untill I checked into it but every where I check I am getting the same voltage as the batteries weather running or not. Thanks for your help.
it's probably not the ECM unless the red light is on. Do you have the 7X1710 probes?
They are the only way to check power to the pins of a connector like that.
Which code(s) do you have?
Resistance checks are not of value in my experience. That system is all about the voltages on the pins of the controller.
At one time you could buy the chip (EPROM) for that controller, but I doubt it's that anyways.
I'd be checking harness code pins. Harness code wire corrosion can tell the ECM it's on a different model machine. (e.g. 312 or 330 instead of 320)
32 hours of troubleshooting at $100/hour for the cost of that controller. I'd be looking to borrow one before spending that coin.
They are the only way to check power to the pins of a connector like that.
Which code(s) do you have?
Resistance checks are not of value in my experience. That system is all about the voltages on the pins of the controller.
At one time you could buy the chip (EPROM) for that controller, but I doubt it's that anyways.
I'd be checking harness code pins. Harness code wire corrosion can tell the ECM it's on a different model machine. (e.g. 312 or 330 instead of 320)
32 hours of troubleshooting at $100/hour for the cost of that controller. I'd be looking to borrow one before spending that coin.
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cjplanthire
Well-Known Member
any time a cat shows high voltage or irregular voltage ,its normally a dead battery ,or the altenator is ******. and sometimes checking the altenator with an amp/volt meter doesnt work because the altenator could still be producing power and tricking the meter, id take the altenator off check the wiring ,and get it checked over!
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I have had the alternator to a repair shop that I trust and was told it was fine. Are the power probes just short wires that hook on the plug and then to your meter because we have those. The red light is not on and I can't find any parts to replace on the computer. I have located a used one for $1200 they still need to check that it powers on but then they will guarintee it to work but not for any length of time. I think this is the way I am leaning as I have more than 32 hours chasing wires with no luck I have a more than competent helper working on this with me and between us and you guys helping still no luck. I think the voltage code was E4 witch in my book was high voltage this is a 9KK ser# machine. I also pulled batteries and switch with my 315B just to check them no difference. What have you found the problem with resistance checks I was just revifying the circit was good and had a good ground. The ecm has no voltage comming out to govenor controler to check. I am not trying to be a samrta$$ I realy just don't understand complecated electrical circuts very well that is why I have someone else helping me on this that does I think and that is what he said to do. What are the code pins and what is their location Thanks for all of your help.
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Nige
Senior Member
The two Cat 7X-1710 (+ & -) probes each have a terminal about 2" long shaped a bit like a half-moon that slides down the outside of the insulation of any wire and into the back of a connector or terminal block so that you can measure voltages in a system without disassembling anything. They connect to the leads of any standard multimeter.
Would a wiring diagram help you..? If so PM me an e-mail address and I will send you one.
The Harness Code connector is right next to the ECM. Check the black wires coming from pins 2, 5, 12, 22, 32, & 33. on the ECM connector. They should all meet at a 2nd connector - that's the Harness Code plug. Make sure the connections are clean and tight. This issue could need a lot of aerosol contact cleaner to solve ..!
Reading your original post it seems as though you have had charging problems (discharged batteries, charging light on) even if those problems are not there now. I'd suggest that you should follow the main wire from the alternator (usually a thicker one than the rest) to the main relay. It will most likely go through a couple of terminal blocks. Bad contacts in these could possibly be the cause of your problems.
Would a wiring diagram help you..? If so PM me an e-mail address and I will send you one.
The Harness Code connector is right next to the ECM. Check the black wires coming from pins 2, 5, 12, 22, 32, & 33. on the ECM connector. They should all meet at a 2nd connector - that's the Harness Code plug. Make sure the connections are clean and tight. This issue could need a lot of aerosol contact cleaner to solve ..!
Reading your original post it seems as though you have had charging problems (discharged batteries, charging light on) even if those problems are not there now. I'd suggest that you should follow the main wire from the alternator (usually a thicker one than the rest) to the main relay. It will most likely go through a couple of terminal blocks. Bad contacts in these could possibly be the cause of your problems.
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We do have the cx 1710 probes. I have the wireing diagran in the service manual. I will check the harness code connector as soon as I get a chance but have a feeling that all conections are clean as all others have not shown any sighn of corosion. I have pull the alt and had bench tested the voltage goes from 26 not runnung to 28.7 running am I wrong to assume that the wire comming from the alt is good. Forgive my ignorance trailer lights are my extent of electrical experiance. All help is appreciated.
John C.
Senior Member
As I recall those alternators have a lead that the computer uses for sensing the frequency to determine the speed of the engine. I know I've seen the Link-Belt line that used the same kind sensing and the rebuild shops did not know of the issue. I ran into another issue on Komatsu alternators where they used another connection to disable the starter if the engine was running. The rebuild shops usually only know how the American units work and don't know of the other systems that are run by the alternator.
If you have the book, there should be something in there about checking all the functions of the alternator.
Good Luck!
If you have the book, there should be something in there about checking all the functions of the alternator.
Good Luck!
Nige
Senior Member
John. Not on a Cat engine though. Speed sensing is done by a flywheel-mounted Hall effect sensor.
Proving that the alternator is making 28.7V when running at the alternator itself is good. Proves the alternator is OK at least. What you have to discover is if that 28.7V is getting all the way to the rest of the system. Hence my suggestion above.
Proving that the alternator is making 28.7V when running at the alternator itself is good. Proves the alternator is OK at least. What you have to discover is if that 28.7V is getting all the way to the rest of the system. Hence my suggestion above.
John C.
Senior Member
I got a little bit of info you might need to check. The A model units do have a speed sensor. They also have an extra wire from the alternator that feeds into the computer. The computer monitors the frequency on that line and compares it to the speed sensor reading somehow. On your alternator you should have the battery terminal, a ground terminal that goes back to the starter and another terminal the Cat book calls the P terminal or W terminal depending on the serial number of your machine. There should only be 14 volts on that terminal.
I've looked over the schematic and didn't see anything else that you haven't already done.
Let us know what you find.
Good Luck!
I've looked over the schematic and didn't see anything else that you haven't already done.
Let us know what you find.
Good Luck!
Thanks John I remember the guy helping me mention something about a 12 volt wire on the computer but thought he said the computer split the 24. I will check that out today and see if I am getting 14 off that terminal on the alt. I know the alt had enough wires to have 2 feeds. Thanks for all the help!