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I received a voltage regulator failure on my 2014 odyssey. It has approximately 90k. I ordered a new alternator and replaced my battery and retested the alternator and it still has a voltage regulator failure. I verified the two connections attached to the alternator and the battery cables. They all seem to be in good condition and functioning properly. Any suggestions on where to look next. My ignorance led me to look for a fuse, but I have had no luck there either.
 

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What was the specific displayed message? Did the check engine light come on? If so, what was the specific code displayed?

Remember that these have a dual mode charging system, so a problem w/ the ELD (very uncommon), or the voltage fed to the C circuit (from the ECM) could hypothetically cause the vehicle to think there is a problem with the voltage regulator (If it is calling for high-output mode, and 'getting' low output mode) - for example, if C voltage (at the alternator) is low (possible from a broken or grounded wire), the alternator switches to low output mode and outputs 12.5-12.9v (vs 14.4ish for high output mode), if the ECM is sending high on C, and sees 12.9v, I'd think it'd bitch about that.
 

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The display inside my vehicle never showed a code or an error. It was only when the battery kept dying and tests were run by the local autozone and o’reillys. After the battery test was complete and they started the test for the alternator, it would say it was starting the test then immediately show the voltage regulator failure. I had this test completed prior to and post replacement of the battery and alternator. At both times, I received the same error code. I have since checked every fuse and relay I can find. Next will be to inspect the electrical lines from the battery, to the alternator, to the fuse box. Hopefully I can find the inline fuse if there is one. I’m a little challenged when it comes to testing electrical and reading what it is telling me.
 

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Ahhhh, I see, so the 'voltage regulator bad' was from the Autozone/O'reilly's test equipment? ... The reason you tested was because the battery kept dying... Now you've replaced both the battery and the alternator, and the symptom is persisting as well as the 'voltage regulator bad' from the autozone/O'reilly's when you then retested?

Is all that correct?


I mean, you are going to need to check the charging system inputs. I'm not confident that the Autozone/Oreilly's testers are accurately accounting for the mode differences, but I've never had to use one, so I can't say for sure.
 

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Lilverdugo, did Autozone test the alternator with it still installed in the van?

The reason I ask is that being that your Honda uses a dual mode charging system (I think they currently all do), if they did this test with a fully charged battery in the van to start with, and no other electrical items selected, you could very well end up in a situation where the Autozone tech mistakenly believes the alternator's voltage regulator is the culprit. Navar is correct.

Also, if the ELD circuit has that grounded wire mentioned above, or the ELD is just not functioning properly (never heard of that, either), well, those could be culprits.

I hope the PCM (powertrain control module) is not the broken link here.

OF
 

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Discussion Starter #6
Correct, the parts store tested the “new” alternator in the van with a new battery. I also had them test the old alternator after I removed it and it showed it passed. I am working on checking the ECM and other options suggested to me. I really appreciate the input. Just slow on testing, busy schedule.
 

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Do you know what the load was on the system while testing? by load, I mean the electrical load. Even w/ the DRLs on, and the van running, the 'load' does not exceed the threshold for turning on the 'high-output' mode. (In this mode, the 'C' line from the alternator, is held low by the ECM, decreasing alternator load on the engine, and increasing fuel economy). However, simply by turning the lights (and brights) on, turning on the fans to max, turning on the radio, you should be able to trigger a switch from low to high output mode.

During the test, was there a high electrical load on the charging system? (which should have triggered the system to switch to high-output mode)


I went back and found a summary of the action of the dual-mode charging system I read years ago... However, I'm fairly confident this all still applies. Let me post a link here: Honda's Dual-Mode Charging System



I mean, based on your description of what's happening, and what you've already shotgunned, my guesses are (in order of likliehood), a wiring fault (specifically, the C line is grounding out somewhere?), an ECM/PCM internal fault (and a wiring fault can cause an ECM fault), or an ELD fault.
 
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I went back and found a summary of the action of the dual-mode charging system I read years ago... However, I'm fairly confident this all still applies. Let me post a link here: Honda's Dual-Mode Charging System
Great minds must think alike. When I opened that link, I realized I'd read that article years ago, too, did a C:\ drive search, and found it's been sitting on my computer. It's a great read on "how it works".

OF
 

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I don't think Auto Zone is the right place to test a vehicle as sophisticated as an Odyssey. One is going to need a dealer grade scan tool. I used to say that it's not 1950 anymore, now I guess one should up that to it's not 2000 anymore.
 

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I received a voltage regulator failure on my 2014 odyssey. It has approximately 90k. I ordered a new alternator and replaced my battery and retested the alternator and it still has a voltage regulator failure. I verified the two connections attached to the alternator and the battery cables. They all seem to be in good condition and functioning properly. Any suggestions on where to look next. My ignorance led me to look for a fuse, but I have had no luck there either.
Lilverdugo,
Did you ever get this resolved?
 

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I just hope he got his OEM alternator back instead oil the crappy rebuild he probably bought from Auto Zone.
If one is having dead battery issues, start with the age of the battery. If over 4 years old that can be it. Next you would want to go through a testing sequence on excessive parasitic draw.
 

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I’m having a similar problem with high voltage. I just don’t see much in this forum about it. Must be a pretty rare problem.


Sent from my iPhone using Tapatalk
 

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As I posted in your thread, your meter is highly suspect. Try it on a different car or get another meter or second opinion from somewhere on that voltage.
 
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