Whining sound from the engine bay and limp mode

April 25, 2023

I apologize for any inconvenience in advance and will try to make this as detailed as possible.

The car is Toyota Avensis T25 116hp 1CD - FTV and about 5 months ago the car started smoking intensely and upon stopping the car the engine stalled and the car couldn't start anymore so the it had to be towed back. The Toyota stayed unbothered for two weeks and started ,thankfully, though there was a check engine light and was smoking still.

The car was towed to, lets name them, 'mechanic 1'. The whole story there isn't a pretty one because all they did is to rev the engine forcefully about 4k RPM to which the car started spilling oil through the exhaust, they said that they are unsure of the problem. All of this seemed kind of insecure to me, probably a mistake I did which I realize over the course of time, so I got my car towed to another mechanic (2).

This mechanic 2 found out the issue is a broken turbine. Thankfully they fixed it and the car was running smoothly. Barely around a month later the car started loosing power especially at hills where it would be most obvious. I presume this is what a limp mode should be. It started making scratching sounds like on a metal after warming up to optimal temperature. I replaced a hose (it was cracked) linked to the vacuum air tank but nothing changed. With each few minutes on the road the car could barely accelerate and eventually end up driving to the mechanic 2 on first gear. They claimed that the car needs injectors changed and after few day the car was done, unfortunately the same night, this sound appeared again this time with a burning smell coming from the engine bay.

The next morning the mechanic came after I informed him and they got the car back to their service. Got it back later that day and they claimed they "cleaned" the EGR valve. The Toyota's condition wasn't any better the VSC, TRC OFF and MIL lights turned on after a week. Of course, I informed the mechanic of what had happened, at this point I was feeling like an idiot for keeping the mechanic busy with my car stuff. They got the car back and it stayed 3 weeks without driving at the service parking lot ,gathering dust, until I eventually decided to get the car back after they told me they tried to look for 5 used EGRs.

I contacted third service to fix the car and they replaced the EGR ,though, the most shocking thing is that this valve hasn't been cleaned or replaced but deleted. Before replacing it - the 3rd mechanic used diagnostic to remove the warning lights and let me drive the car, interestingly enough this didn't feel like the same car, the acceleration was much better than ever before, the car was really fast and was really smooth driving. I returned to them to tell that the car was very good right now, they set up a test through the diagnostics and a whining sound coming from the engine bay. They replaced the EGR valve and the acceleration disappeared like it was beforehand.

Eventually I decided to work on the car on my own, brought diagnostics and started working on it. Waited for the warning light to come on again. They showed C1201 and P0400. I had no idea where to start from. The injectors and the head cover were sealed with a glue (silicone?) for high temperature use. I'm aware that this is used ,of course, but this silicone had dripped all over the engine and the injectors have slight drops of oil after a bit driving. I'm not aware if there is any head gasket though. The whining sound appeared upon revving up the engine, which is heard in the end of the video. Following the DTCs I checked the MAF sensor and air intake temperature sensor as well as the MAP one. The MAF sensor calculated amount of 15 g/s in the air intake. Checked every hose around the EGR and the following hoses. I found out that the turbo vacuum solenoid (25819-27050) is broken, at least the part where a filter is supposed to be, checked the resistance as well, although it barely reaches a 100 Ohms at 20 degrees Celsius, ordered a used one or cheaper price and waiting. A DTC of C1201 is still on after got the diagnostic connected. The only DTC after the Battery got disconnected and connected shortly before diagnostic. Aside from issue with the engine control system, ABS and traction system, what is actually the problem, especially in correlation with DTC P0400?

My point of the post is what should I expect from all of this and if the problem still persists even after I replace the solenoid what should I look for next? I have got a video of the engine sound so any opinion on it is welcome and I will be grateful if anyone can tell me what might be wrong. The whining sound is in the last few seconds.

Thank you in advance!

Link leading to the video