Clicking noise, revs decrease and increase

Welcome to 2CarPros.

That doesn't sound normal. Can you tell approximately where the clicking sound is coming from? Also, how low do the RPM's drop? Once last question, if the sound is coming from under the dash, does it do it if the climate control is completely off?

One last request. Can you record the noise and upload it for me to hear?

Thanks,
Joe

Based on your video, the clicking sounds like the AC compressor engaging and disengaging. When it engages, it puts a load on the engine, but the computer should compensate for that and increase the RPM's so you hardly notice it. Since it seems to be related to the compressor engaging, I question if it is in the process of locking up.

What I need you to do is locate the AC compressor. It is one of the belt driven accessories. I added a picture of one so you can see what it looks like. Now, here is what you need to pay attention to. With the engine running, locate the compressor and pay attention to the center portion of the pulley which is driven by the belt. When you hear the click, see if the center starts spinning or if it stops spinning. I know that sounds crazy, but there is an electric clutch that locks the center portion so it turns the compressor. When it is disengages, the outside will continue spinning and the center will stop.

Try to do that using a flash light to see. Just keep away from the moving parts.

Let me know what you find.

Joe

Welcome back:

Okay, that is the compressor for sure making the noise. When it engages, it does put a load on the engine. However, there is a thing called a stepper motor that should increase the idle speed so you don't notice the change very much. If the engine isn't stalling but the RPM's are lowering, that is normal. However, it should not stall the engine.

Don't be alarmed by the clicking sound. That is normal. There is an electromagnet that receives power and quickly engages the compressor. Because the magnet is both strong and quick, you hear the click. Also, if you hear it with the defroster on, don't be alarmed. The system is designed to engage the AC compressor to help dehumidify the air entering the vehicle to defrost the glass quicker, so it will turn on and off then, too.

I didn't see your other link. If you can, copy and paste the link for me and I'll look at it for you.

For this issue, if the RPM are slightly dropping, it's normal. If that changes and the engine begins to stall or you hear a loud squealing noise when the compressor engages, let me know and I help you get it fixed.

Take care,
Joe

OMG, you are very welcome. I will take a look at the other link and let you know what I think.

Welcome back, Sandy. I had a feeling it had something to do with an alarm/anti-theft issue. Listen, if the part he is referring to is not an original equipment Toyota component, get rid of it. It could be something that was installed after it was purchased.

I had a person bring in an Audi convertible because the top wouldn't work. Someone installed a "quality" anti theft system which had a special FOB which also opened the top from outside of the car. The Audi dealer wanted nearly $3,000.00 to replace the power top control module. I inspected the module, seen there was an additional component plugged into it, removed it, and the top worked great. LOL The customer was much happier with a $35.00 labor fee. LOL

What I am saying is this. Anytime aftermarket components are added, anything can go wrong. If in fact someone installed an aftermarket anti theft system, personally, I would remove it.

Let me know if I can help. Also, I'm happy to help, and you are welcome here anytime you have a question.

Can I ask you for a favor? Is it possible for you to copy and paste your last post to the original thread regarding this issue? We try to keep them consistent so they help others.

Take care,
Joe