Cat 289D3 high voltage alarm

[TXRweather]

I have a 2021 289D3 and upon starting it this evening, it threw first, a amber alert on the HMI that it had detected high voltage. After a few seconds, I got the explanation point in the diamond idiot light, a beeping alarm and the amber alert changed from amber to red on the HMI. It gives me a message of: High system voltage. Check the battery and the alternator. E876-3

The machine ran fine all this past weekend. This is something new. Oh, the serial of the machine is: JX906025.

Any one had this issue and besides the alternator and battery, is there anything else I should be looking for?

 

[Mr. Wrench]

Voltage will not rise higher than it's source. The alternator is the only thing that can raise voltage above the battery voltage ( 12.66V fully charged). Have you checked the voltage yet at the battery, and at the alternator with it running? Make sure the connections on the battery, and alternator are good and no corrosion. Also make sure the grounds from the battery to the engine and to the frame are good. Take them all off and clean them until they are shiny and bright. One thing that can happen is if there is corrosion in the circuit to the alternator it can think that the battery voltage is less than it really is and thus end up over charging the battery. The alternator itself could also be bad. Need to check some voltages to know what is going on.

Be patient, Nige will be along with more detailed instructions...

 

[Nige]

From memory E876-3 indicates that the machine system voltage has exceeded 14v. that's why the displayed message on screen requires an immediate engine shutdown.

First thing to suggest is to check the voltage across the battery and at the alternator output terminal with the engine idling and also with it at max RPM.

 

[Simon C]

The alternator output cable is CBL-AA2RD-4 and goes direct to the Positive post of the battery. Cable from alternator to Battery positive should be tested in case of internal flaw. If alternator senses too low of voltage it will put out maximum to try to correct the situation.
Red meter lead at Alternator positive post and Black meter lead on Battery Positive post with lights on and heating fan on to force current through cable and any reading over 0.4 volts is something wrong with cable. Also as Nige said check the voltage at battery to see what it is doing.
Simon C

 

[TXRweather]

Thanks for the replies. It was about to get dark tonight when I took the Cat over to the truck to be fueled up when it threw the code, so I didn't get a chance to check anything. I'll have some time to check it tomorrow. It may very well be the battery posts need cleaning. I'll check in tomorrow night and let you know what I found. Hopefully, it is a simple fix.

It threw a low voltage code back a few weeks ago during the Ice storm we had. That was due to freezing rain dripping down on the alternator, freezing it in place and the alternator belt was fairly loose. The ice melted and I tightened the belt, which seemed to resolve that problem.

 

[stinky64]

Maybe should have mentioned that little diddy at the start. Frozen alternator/water in the alternator, what could go wrong?

 

[TXRweather]

Maybe should have mentioned that little diddy at the start. Frozen alternator/water in the alternator, what could go wrong?

See? This is why I come here to ask what seems to be to some, rather dumb questions. A wealth of knowledge amongst a big group of heavy equipment owners, which I appreciate......and then the MMQB's......

 

[TXRweather]

As promised, I am letting you all know what I found.

Since my initial message, I tried using the CTL again, and this time, it threw another low voltage alarm. Today, I checked the voltages with a DVM and sure enough, the alternator wasn't charging. Battery voltage was right at 12VDC while running. I checked all grounds, the battery terminals and ran a ohm check between the battery negative, battery negative switch, chassis ground and the engine ground. All less than 1 ohm. Checked all 12VDC positive connections on the battery and alternator. All were tight and clean. Pulled the alternator out and saw the rectifier heat sink cooling fins were plugged solid with dirt. Cleaned with compressed air. Took the alternator in and had a test done on it. Alternator was not putting any voltage out. So, just ordered a new alternator. They are sure proud of them. Hope to have it running by next weekend. I suspect the cooling fins being plugged with dirt probably caused the rectifiers for the voltage regulator to over heat and weaken over time.

I bought this machine used and it appears that general maintenance of the motor compartment was not very high on the previous owners list of things to do. Luckily, he did have a service contract with the local Cat dealer, so the fluids and filters got changed when needed. I cleaned almost a 5 gallon bucket of dirt and gravel out of the engine compartment yesterday. Previous owner appeared to grease everything, which is good. He also had the track tensioners over greased and had over tensioned the tracks, causing the steel cords to break in one of the tracks last fall, which made the machine keep throwing tracks and I ended up having to buy new ones and change them out. Still happy with the machine. Just have to get the last of the gremlins out of it. Now, for the backup camera glitch.......

 

[Simon C]

As promised, I am letting you all know what I found.

Since my initial message, I tried using the CTL again, and this time, it threw another low voltage alarm. Today, I checked the voltages with a DVM and sure enough, the alternator wasn't charging. Battery voltage was right at 12VDC while running. I checked all grounds, the battery terminals and ran a ohm check between the battery negative, battery negative switch, chassis ground and the engine ground. All less than 1 ohm. Checked all 12VDC positive connections on the battery and alternator. All were tight and clean. Pulled the alternator out and saw the rectifier heat sink cooling fins were plugged solid with dirt. Cleaned with compressed air. Took the alternator in and had a test done on it. Alternator was not putting any voltage out. So, just ordered a new alternator. They are sure proud of them. Hope to have it running by next weekend. I suspect the cooling fins being plugged with dirt probably caused the rectifiers for the voltage regulator to over heat and weaken over time.

I bought this machine used and it appears that general maintenance of the motor compartment was not very high on the previous owners list of things to do. Luckily, he did have a service contract with the local Cat dealer, so the fluids and filters got changed when needed. I cleaned almost a 5 gallon bucket of dirt and gravel out of the engine compartment yesterday. Previous owner appeared to grease everything, which is good. He also had the track tensioners over greased and had over tensioned the tracks, causing the steel cords to break in one of the tracks last fall, which made the machine keep throwing tracks and I ended up having to buy new ones and change them out. Still happy with the machine. Just have to get the last of the gremlins out of it. Now, for the backup camera glitch.......

I blow out my alternator on my vehicles every oil change, as well as any equipment I am servicing. Some are right packed with dirt and definitely overheating.
Just for your reference for next time , now that you have it charging, An Ohm meter will only tell you from one end of a wire to the other that there is a path. It tells you nothing about the strength of the path. Get a rope 1 inch diameter to tie to a roof with only one strand left visibly, will you even go on the roof knowing it will let you down, no chance. Neither will a ohm meter tell you if there is only 1 strand left at some point in the middle of the cable. Nothing will work correctly, and you will be let down or embarrased after changing parts only to find out there is no path to ground.

In post #4 above was mentioned the correct way to tell if for example your alternator cable is junk.
The same technique is used to test any ground cable back to Battery Negative post center whether from the frame or cab or computer. The only difference is the amount of loss that is acceptable.
From Computer Ground to Battery Negative post 100Millivolts is lots on a 12 volt system as this is just a micro-amp current.
On a frame to Battery Negative Post center a loss of 0.5 Volts is maximum, and it is higher because there can be 100-1000 amps flowing. Current has to be flowing for any of these test to work or give accurate readings. Testing while cranking and with fans on and lights on will test the cables well.
Positive cables are tested in same way.
Hope this helps. Any questions fire away.
Simon C

 

[TXRweather]

I blow out my alternator on my vehicles every oil change, as well as any equipment I am servicing. Some are right packed with dirt and definitely overheating.
Just for your reference for next time , now that you have it charging, An Ohm meter will only tell you from one end of a wire to the other that there is a path. It tells you nothing about the strength of the path. Get a rope 1 inch diameter to tie to a roof with only one strand left visibly, will you even go on the roof knowing it will let you down, no chance. Neither will a ohm meter tell you if there is only 1 strand left at some point in the middle of the cable. Nothing will work correctly, and you will be let down or embarrased after changing parts only to find out there is no path to ground.

In post #4 above was mentioned the correct way to tell if for example your alternator cable is junk.
The same technique is used to test any ground cable back to Battery Negative post center whether from the frame or cab or computer. The only difference is the amount of loss that is acceptable.
From Computer Ground to Battery Negative post 100Millivolts is lots on a 12 volt system as this is just a micro-amp current.
On a frame to Battery Negative Post center a loss of 0.5 Volts is maximum, and it is higher because there can be 100-1000 amps flowing. Current has to be flowing for any of these test to work or give accurate readings. Testing while cranking and with fans on and lights on will test the cables well.
Positive cables are tested in same way.
Hope this helps. Any questions fire away.
Simon C

I will have to make one clarification. When I said I was using an ohm meter, I did not have it set on the standard beeping continuity test. I know the positive and negative wires and cables had continuity. I performed a ohms resistance test, with my DVM manually set to milliohms. I was checking for differential resistance, down to half an ohm level (500 milliohms). While checking, I also wiggled the wires/cables/connectors to see if I was getting any change in resistance at the half ohm level. That, to me, would indicate a flaky or poor connection. A slightly higher resistance reading in milliohms from point A to point C than a resistance reading from point A to point B would tell me that I have a imperfect connection somewhere between points B and C. Finely stranded copper wires and cables don't typically break in the middle, unless they have been pinched, burned, corroded or mechanically stretched. The failure is usually at the the crimp connection at either end, or the connector pins and sockets has dirt, oil or corrosion on them. Another cause could be a deformed pin or socket at one end. Finely stranded wire and cables used in automotive electric are intentionally designed with small diameter strands for flex movement without breaking. That is why your main power cables are typed as weld cables or DLO. If I have suspicion that the connector has a bad or flaky connection, I use a wire/cable piercer attachment on one of my DVM leads to check the copper wire conductivity inside of the wire insulation to both points A and B.

If you suspicion that you are loosing voltage, due to a bad connection, you can also use a Thermal Camera to detect warmer spots on your connections. A voltage drop is due to resistance, which creates heat.

No, I do not have a dedicated 4 wire milliohms meter. I have a Fluke 87V that has been recently factory calibrated to read milliohms down to 100 with a tolerance of ±(0.2% + 1)

Good suggestion on blowing out the alternator after every oil change. I don't have enough hours on my machine since the last dealer service was done on it by the previous owner. But, I will now blow it out every-time I rinse the engine compartment out. I am a old fart that is still learning.

 

[AMBMike]

I will have to make one clarification. When I said I was using an ohm meter, I did not have it set on the standard beeping continuity test. I know the positive and negative wires and cables had continuity. I performed a ohms resistance test, with my DVM manually set to milliohms. I was checking for differential resistance, down to half an ohm level (500 milliohms). While checking, I also wiggled the wires/cables/connectors to see if I was getting any change in resistance at the half ohm level. That, to me, would indicate a flaky or poor connection. A slightly higher resistance reading in milliohms from point A to point C than a resistance reading from point A to point B would tell me that I have a imperfect connection somewhere between points B and C. Finely stranded copper wires and cables don't typically break in the middle, unless they have been pinched, burned, corroded or mechanically stretched. The failure is usually at the the crimp connection at either end, or the connector pins and sockets has dirt, oil or corrosion on them. Another cause could be a deformed pin or socket at one end. Finely stranded wire and cables used in automotive electric are intentionally designed with small diameter strands for flex movement without breaking. That is why your main power cables are typed as weld cables or DLO. If I have suspicion that the connector has a bad or flaky connection, I use a wire/cable piercer attachment on one of my DVM leads to check the copper wire conductivity inside of the wire insulation to both points A and B.

If you suspicion that you are loosing voltage, due to a bad connection, you can also use a Thermal Camera to detect warmer spots on your connections. A voltage drop is due to resistance, which creates heat.

No, I do not have a dedicated 4 wire milliohms meter. I have a Fluke 87V that has been recently factory calibrated to read milliohms down to 100 with a tolerance of ±(0.2% + 1)

Good suggestion on blowing out the alternator after every oil change. I don't have enough hours on my machine since the last dealer service was done on it by the previous owner. But, I will now blow it out every-time I rinse the engine compartment out. I am a old fart that is still learning.

All good points.
I'd encourage you to note your use of the words "typically" and "usually". The tests you have performed will work in the "usual" and "typical" situations but will give false positives in a number of others.
Do you know beyond a shadow of a doubt that your situation is typical and usual?

The tests posted by @Simon C will work in the situations that are unusual and atypical in addition to the usual and typical and take no more time to perform. In addition, they are one and done, pass or fail tests. Your 87V meter is more than enough to perform his tests. In fact, they could be done by a teenager with a $10 Harbor Freight meter.

Troubleshooting off highway trucks and heavy equipment is similar in many ways to automotive and on highway trucks but teaches you quickly to expect the unexpected.

This is an excellent opportunity to "keep learning".

 

[Nige]

One thing that working with equipment has taught me is that most "rules" that include the words "normally" and "usually" can be thrown out of the window right from the start. To work on the premise that everything in the electrical system is farked until proved otherwise is always a good starting point IMHO.

I'll be honest and say that the only way I would suggest to test the load carrying capability of a particular typical 14-18 SWG wire found in one of these machine harnesses would be to first disconnect both ends of said wire, connect one end to machine frame ground and then supply the other end with batt+ via a fused 5A test light. Any wire that will carry 5A without exploding should be able to be classed as good.

This applies particularly to wiring that is used to carry what I refer to as "delicate" signals such as the output of PWM-type sensors (even though the current in that case is negligible), or on the other extreme wiring used to carry relatively high currents to solenoids, etc.

My 2c. YMMV.

 

[Nige]

To continue a little further on the same theme.........

Based on the number of issues that have been addressed on this forum over the years it appears to me that the Compact Equipment product line (Skid Steers, CTL, and MTL machines) generally suffer across the board from a lack of "slack" designed and/or built into their wiring harnesses. This especially applies to the engine wiring harness.

The result of this is that at any location where a harness is pulled into a tight curve, or where a zip-tie pulls a harness tight on to a ladder clip, there is a possibility of vibration-induced failure of the individual strands of any particular wire inside said harness with absolutely no external indication that anything is amiss. For some reason this appears to be particularly prevalent with the wires that carry the medium & high speed CAN+ and CAN- signals and I have no idea why.

That's another reason for load-testing wires within a harness. Often if they pop there may generally be at least some external indication.

If you suspicion that you are loosing voltage, due to a bad connection, you can also use a Thermal Camera to detect warmer spots on your connections.

A good point, but thermal cameras, although they are a lot cheaper/more common than they used to be, are still not standard in most diagnostician's tool box.

 

[Simon C]

Can't beat the 5 amp bulb to test a wire disconnected from harness plugs from end to end.
But when it comes to Big 6 gauge and up wires or up to 00 size cables used on alternators, Grid heaters, or the main Battery cables and Ground cables, it is hard to beat a pulled fuel fuse to disable start and test the cables with heavy load for 5-7 seconds.
I usually hook up both my Fluke 87 meters at the same tiime, one on the battery positive to Starter Solenoid Positive, and the other on the starter frame back to Battery negative post.
One start attempt and quite a lot figured out. Then after looking how much loss I had, I will test the frame ground back to Battery Negative as well as the cab ground back to battery negative in one test.
If it can start after these couple tests I will check the Alternator Positive output to Battery Positive with one meter and the other meter to check from Alternator Positive to Battery Negative with meter on AC millivolt setting to check for alternator ripple voltage when alternator kicks in with all lights on and fans on to force alternator to put out heavy.==== To help hook up to the Alternator output post if it is small I have some quality 5 inch long vice grips that I clamp very tight to the output stud so as to be able to hook up two sets of alligator clips to it at once. That is a little trick I do to hook up meter leads securely to prevent wacky readings.
Simon C

 

[HarleyHappy]

My experience, when it comes to electrical, very rarely are things normal or usual.
Electrical can be more frustrating than getting spouse on same schedule as your own, especially on carnal knowledge.
By doing some simple and very informative tests, hours if not days can be saved.
Just remember, how many threads have been starting with “ but all the grounds look good and all the connections are great and my battery is new”. We see battery posts with vice grip marks, connection with broken tabs, cable crimps with hammer marks, cables or connections with green stuff and my favorite, small holes all over the wiring insulation, from pointy things.
Then the majority of the time, said thread dies because the OP finally found that bad ground or broken connection and quietly disappeared in the night.
Thats why I always give a ”like” when they come back and tell their tale!

 

[Mr. Wrench]

Alot of good advice in the last several post. If there is one thing that working on electrical systems will do, is it will keep you humble or make you go nuts. About the time you start to be too confident and assuming things, it will throw you a real curve ball that you have never seen before. Diagnose with confidence but don't skip steps. "Looks good" is not checking. Taking readings with a VOM is getting data and will tell you go or no go.

Some thoughts on using ohms readings. Ohms readings are mostly just good for testing a part on the bench that is removed from the machine. The VOM does not put out enough voltage to see if a circuit can carry much of a load. If the circuit you are checking ohms on is not isolated you can become really confused. They say," electricity takes the path of least resistance". I think it is more accurate to say, most of the electricity takes the path of least resistance.

Most of the test you do on equipment is, voltage, voltage drop, and load testing. Sometimes you need to check amps and ohms.

 

[TXRweather]

Just a FYI, I replaced the alternator and it started charging right away. Ran it for about an hour tonight. Voltage is stable. Thanks everyone for your troubleshooting tips.