High pitched scream from my 2002 Tundra when off

I was camping this weekend. It was misty and cool weather. The truck was sitting not running for about 24 hours and suddenly there was a high pitched noise wailing from it. Popped the hood and a nearby helpful man came and disconnected my battery. It stopped. We found info on this thread that it was the piezo. We reconnected the battery and about 5 mins later the wailing started again. So loud and piercing. We disconnected the piezo and it didn’t sound again with the battery connected. However, I heard a lot of flushing noise from the engine compartment that went on for a long time all nigh it seemed. Woke up and went to start the truck…battery was dead. Jumped battery but truck would not start. Reconnected the piezo and it started. So my question is what is the piezo tied to and what do I need to fix?

As a follow up. We loaded up and the high pitch started again a few mins after the truck was jumped and running. Everything was running fine. Just loud ass scream from under the hood. I drove 1.5 hours home. Disconnected the battery. Unloaded. Reconnected the battery and backed it into my garage. It has been home in the garage with the battery and piezo connected for 4 hours now and no noise yet. What is going on with my truck? What do I need to do?

 

My 2000 doesn’t have either but I’m thinking either SAIS or keyless entry piezoelectric buzzer. p/n 08192-12921

 

This has happened to me before. There’s a piezo electric connector you can undo near the driver’s side evap canister and leave unplugged for a day or two.

Plug it back in thereafter and see if the piezo speaker goes off. Usually it’ll fix itself.

I attribute it to maybe water condensation or a poor connection, but it hasn’t happened again for over a year.

 

Replace the piezo. Doesn't explain the battery drain, but the part you need is in reply #11 here: https://www.tundras.com/threads/03-...histle-while-truck-is-off.56902/#post-1487460

 

Thanks everyone. It still hasn’t started screaming again yet. Maybe it fixed itself. I may order one just in case. I appreciate the feedback. What does this buzzer relate to and is it needed? Apparently it is there for a reason. Also, the logic is that it starts wailing when it is failing? Such a loud screaming buzzer but why? What purpose does it have when it isn’t screaming?
Thanks again.

 

Every alarm/anti-theft system comes with a piezo to chirp when you lock/unlock, and to screech out a pulsing sound during intrustions. If it's ever going full-blast, monotone, that's a sign the piezo likely has water in it (got flooded) or is failing. It's important the end doesn't fill up with water.

They're inexpensive to replace.

 

Perhaps something else like the “brain” for the keyless system is what failed, with the speaker tone being only a symptom but not the real problem. Or even one of the control modules, Hence the additional noises heard that killed the battery overnight. Think the piezo chirper is throwing you off the scent.

 

First place I went to with the latter wasn't the brain ... I was convinced we had another victim of a-pillar water leaks into the in-dash fusebox. Feel like we've definitely seen an uptick in those lately.

But if there's nothing else electrical odd going on, it's probably water in the piezo. One of two things usually happens: It stops/muffled chirping, or it screeches constantly. I think the latter happened to PHM at one point too. We've had a number of reports of piezo failure causing perma-screech.

 

All this is excellent information- thanks for the responses.

 

Do you have keyless entry on your truck? If you don't have a remote you can either add one or just disconnect the keyless entry system. There shouldn't be any reason you can't cut out the piezo. That alarm system cannot keep the truck from running, unless it has some other type of aftermarket alarm installed as well.