Here's the backstory, Knock Sensor CEL 52 & 55.

1993 SC400 - 1UZ-FE

Replaced both front bank 02 sensors
Replaced cap, rotors, wires, plugs
ECU - serviced (Tanin Auto Electronix)

Knock sensor harness custom rebuild - Marti Racing

Still have my check engine light come on within 5 minutes of driving my car.

Symptoms - Car acts very sluggish on acceleration (0-25mph) pumping the gas pedal is needed to get it to (accelerate "normal")
Tachometer does not go past 4000rpm .

Suggestions (per marti racing)
Replace my ECU

Okay Club Lexus.... This problem & cat and mouse game has been going on for well over a year. I need this problem fixed. It's my daily driver. Please, does anyone have any suggestions / solutions for me at this juncture? Thank You.

 

Might be worth asking Tanin if they carefully checked the ECU's circuit board traces where the harness connects. Mine was pretty badly water damaged there and resulted in the knock sensor CELs. It would be easy to miss if you weren't looking for it, though.

Borrowing a known working ECU would be a great process of elimination step.

It's a long shot, but it could be that the knock sensors are actually bad. That would be pretty costly, or pretty time consuming if doing the work yourself.

 

I guess I did forget to mention, Yes, I replaced both knock sensors as well.

As for a known working ECU, that's my dilemma, At this point, since there hasn't really been anything else that has been discovered along the way that could be throwing these codes. I'm rather positive that it is the ECU. If I knew of a known working one, I would just buy it and swap it. I personally can't afford to send mine up to Tanin (again) and get into a rental car for another week. Not fun spending 535 dollars for a custom knock sensor harness and 5 days worth of rental car, only to be told that your ECU is bad.

 

We can easily find you a replacement ECU, rebuild it, ship it to you, and apply a portion of what you already paid to the purchase of it.

We clean boards, replace capacitors, repair damaged traces, and ship it back. We don't have cars or designed test benches here to power the ECU on and test every input/output. If we did the cost of a rebuild would not be sub $100

With that said there certainly could be components that visibly appear fine, but are "bad". There really is no easy way to test it without swapping in another ECU.

 

^ Always great to see that level of support!

When I saw the damage to my board after the input terminals were all removed, I totally understood why my local tech was hesitant to try fixing it. He ended up forging ahead while I was searching for a replacement, but like Tanin said, few people are set up to be able to run a ECU through all its functions. Fortunately, he did a stellar job repairing the traces and appears to have corrected all the damage, but there's a certain amount of trial and error involved in catching everything.

 

Couldn't agree more ... Thanks Jason. If you want to get in contact with me about your idea, please contact me via the private message box, or feel free to contact me at 417-825-7231. Thanks a bunch, and for thinking outside the box! Hope you have a good weekend. -- Aaron

 

Couldn't agree more ... Thanks Jason. If you want to get in contact with me about your idea, please contact me via the private message box, or feel free to contact me at 417-825-7231. Thanks a bunch, and for thinking outside the box! Hope you have a good weekend. -- Aaron