So I was having the a knock sensor problem(code 52) as so many others have. I had my engine rebuilt on my 1993 T100 3.0 3vze and the code 52 popped up as soon as we started it up. We replaced the knock sensor and harness....still code 52. I ran a new shielded wires to ecm...still code 52. Anyway we ended up going through two OEM knock sensors from the dealer(one was confirmed defective and got a replacement). We finally picked up a Denso knock sensor and eureka!!! Code 52 gone!!! The knock sensor from the Toyota dealer has a blue band(see pic),for some reason it did not work. I also include a pic of the Denso. Hope this helps those looking to solve the code 52.

 

If one worked and one didn't I would look at the caps on your ecu. One might have a better signal strength that the ecu can process. Sounds like the cap.might be getting weak. Mine was 30% under spec when it stopped working.

 

I just got a knock sensor straight from Toyota, and it is neither of the ones you have pictured. Hope it works! *fingers crossed*

 

Can anyone else report success when switching new style with old style knock sensors? (89615 50010)

Did the knock sensors look like this YPO?

Denso on left, Toyota denso on right