Honda Odyssey issues - dead battery, then loud buzzing and smoking from engine

Having issues with 2009 Honda Odyssey. I’ll describe, but I can’t be certain these things are related.
This morning, battery was dead for no apparent reason. No lights were left on, etc. Battery is brand new.
After jump-starting, car ran fine for a few moments, then starting making loud intermittent “buzz” sound from engine/radiator area, down inside maybe on the left side of the radiator. There was also smoke rising from the engine.

I don’t know much about cars, unfortunately, but cursory research suggests it might have something to do with the AC system.

I have attached a MOV which captures the sound it was making.

Any thoughts or advice appreciated.


That noise might be the ABS module going thru it’s self test mode.

The wife’s Accord’s ABS module makes the same noise when it goes thru it’s self test mode.

The smoking?

That’s got be investigated.


If the battery was dead prior to you running the engine…Usually after a jump start the Alternator could make a lot of noise because of all the voltage it needs to pump into the battery. I couldnt play your file on my laptop so I didn’t get to hear the noise unfortunately…so I am just guessing at the moment.

However many times I have witnessed vehicles with dead or very low batterys that have been jump started …and their Alternators make more noise than normal and or the Alternator can actually lock up which would make the belt squeal like crazy…Not sure if you smelled burning rubber associated with this noise. Make sure your batt connections are VERY Clean and tight as well to ensure that the Alt can get the voltage it generates into the battery.


You may have already figured this out but this exact thing happened to my 2008 Odyssey. The issue is that the AC Clutch relay is stuck. What happens is, the clutch for the compressor stays engaged even when the car is off and creates a parasitic draw on your battery…which is why it is dead every morning. It is also the reason your car was making that noise and smoking after you jumped it…the compressor was engaged all the time even when the air was off. All you have to do is go to the fuse box under the hood on the left side as you look into the engine (passenger side). Pop off the top of the box and its a little black rectangle plug in that is farthest left and closest to you. It shows a picture of a snowflake for this on the bottom of the fuse box top. It’s about a 6 dollar replacement at an auto store. Hope this helps!


Adding all the symptoms together, including the stinky smoke, I’d first suspect a seized alternator bearing.

Did you ever figure out what it was? I had the exact same thing as you described happen to my 2009 Odyssey this week.

Did you try doing the experiment of removing the AC clutch relay as described 3 posts above @sandwichking959 ?

You are awesome! Same exact symptoms on our 2010 Odyssey. Completely 100% dead battery for no reason. After jump starting, it was about a minute later when the LOUD buzzing, almost “sizzling” sound started. I shut off the engine as soon as I saw the smoke. I couldnt pinpoint the source of the sound or smoke but it seemed to be down inside toward the left of the radiator, just as described. AC clutch relay did the trick. Easy to replace, cheap part, now I’m wondering what the repair shop would have charged me. Thank you!!

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So glad I found this thread. Over the last 2 weeks our battery has died 3 times. The first time lights were left on so we just figured it was an old battery. I jumped it today, figuring I’d take it to auto zone for a free replacement because it’s under warranty. As it was sitting there idling a terrible loud intermittent noise came on. I heard it inside my house and ran out to the garage and instantly turned off the car. Inside the hood there was smoke and bad smell. We restarted it and everything was normal, got the battery replaced , oil changed, mechanic checked it out and couldn’t find anything. I brought it home and the sound came again, again with smoke from under the hood. We were worried this time so we towed it to local mechanic (thanks AAA for free towing.)

It sat at the mechanic garage all day, mechanic couldn’t get it to reproduce the sound. Tried driving it, idling it, tried with AC on, and AC off, then I came across this thread and told him.

I drove back to the shop and realized the hood was up. I closed the hood and within2 minutes , the sound started Again. Not sure why the closed hood made a difference? Airflow maybe? The mechanic said the smell was definitely a freon smell.

Anyway, went to auto zone, bought a relay switch for 8 bucks like you said, and it’s all fixed.

Mechanics had it there all day and couldn’t figure it out. You guys saved me thanks .

I went through same issue for my 2009 Honda Odyssey , this thread helped me to save thousands of dollars.battery was dead, jumped started again battery was dead in 6hrs time, jump started it and again battery was dead, replaced battery under warranty, went through same issue again, Mechanic checked and said need to replace gaskets, timing belt, …but i was skeptical, started searching online found this thread and replaced “AC Clutch relay” now all set

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