I just inherited a 01 RX300 with 193k mi and have the infamous P0325 & P0330 CEL. I wanted to verify if the fake Denso KS’s on Ebay could possibly work on this vehicle without wasting $$ and a weekend on labor to find out if the ECU would reject them. Therefore, I spent $20 dollars on an Ebay seller for a pair of “OEM Denso” KS’s w/ fake harness and spent $1 on a steel plate (cut in half) from a big box store. I also picked up several nuts 1.25x12 iirc from the big box store to secure the KS’s temporarily to the temp brackets. I confirmed the fake sensors were properly grounded on my temporary brackets mounted to my valve cover and was able to obtain ac voltage by tapping the brackets with a ball peen hammer. Please note: the 1st gen KS’s are more accommodating to perform this temp bracket test than the 2nd gen RX KS’s. With regret, the ECU rejected these fake sensors similar to the many members have experienced in this forum. Therefore, I ordered “real” KS’s and harness from Toyota for $412 and conducted the test again with my temp brackets. The ECU accepted Bank 1 but still rejected Bank 2. I then swapped the wires at the KS’s and Bank 2 is still rejected by the ECU. I then pulled the connector on the ECU so I could check the full-length wiring and I confirmed continuity/ohm on both the black and clear wires. Thanks to Bobster for Identifying these RX wires previously. Since I don’t have access to a scope, I could pay the stealer to confirm if the ECU is bad on bank 2 but I will probably skip and just perform the infamous Bobster hack. When intake and VC gaskets, plugs, and hoses arrive, I’ll tear into it and install these “gold plated” KS’s over the weekend and probably throw in the hack. I’ll also install a stud at the rear PITA bracket for easy reassembly…

Nice try.

What I want to know is what the ECU is looking for?

An engine with 193K prolly does not really need a KS to survive ... It's loose enough to run OK with a little ping now and then

I’m not sure what the term loose means or how it relates to pre-ignition. However, I have read my RX model utilizes the resonance version of the KS and it is my understanding my ECU may be looking for a constant 7.6 kHz. My cheap DVOM can’t read this and I don’t have the FSM so I can’t confirm currently. I did pin to ground the KS inputs on the ECU and both terminals read 3080 ohms. It is also my understanding ECU’s can fail due primarily to age, leaking capacitors, etc. I would like to get my hands on the ECU schematics and tear open my ECU to rule out failure….

Aging capacitors are the number 1 cause of older electronic equipment failure ...

I wish we could get to the bottom of this circuit ... It'll cause a failure to pass SMOG testing, even though the engine runs fine.

At 7.6 KHz, that 3080 ohm will be a different value (AC vs DC resistance). But as long as we can get some numbers to work with, maybe a bread board could be built to supply the desired signal ...

I couldn’t locate any troubleshooting/resolution in this Gen1 forum why the Bobster KS hack didn’t work for numerous other members, including myself, as of yesterday. Please correct me if I missed it. Therefore, I will be sharing my journey of this fix in effort to help anyone interested with this condition.

Iirc, I didn’t recall anyone giving any info at the ECU KS pin outs. As I don’t have any schematics, I decided to share my 3080 ohms data as a reference.

Additionally, I just ordered a $100 reman ECU from ebay and will be comparing it to mine to establish baselines. I’ll also verify if the 30 minute obdII jumper pin hack will program my ebay ECU as I don’t recall anyone confirming this on a Gen 1 …

Can you show pics of your KS pin out jumper hack. (ECU connector)
Not doubting your work as it seems like you know what you're doing.
But it doesnt hurt to get others opinion.
If you dont mind that is.

Please refer to Bobster999 post for in-depth explanation and pictures of this KS Hack…

It's yours i want to see.
How you did it.

Here is some cool stuff for anyone who wants to take it further.

Not a schematic but a simple drawing showing a capacitor inside the ECM- might be able to use an ESR Meter to test this cap without removing ECM(battery and sensors disconnected and observe proper handling and ESD precautions) for someone skilful with electronics if the capacitor is electrolytic style.

* Capacitor ESR Test Note- ECM Connector E9(pin 27) to ground for Knock Sensor Bank 1 and then ECM Connector E9(pin 28) to ground for Bank 2. You can use Connector E9(pin21 or pin 31) for ground for this test according to the ECM Pinout. This test will only work for electrolytic style capacitors- ceramic capacitors fail differently and this won't usually work- resistance test will be better for ceramic style(in circuit) or pulled from circuit board to test properly but would require opening ECM but ceramic style capacitor rarely fails(a unicorn) in an application like this but who knows but I suspect it is a ceramic but not sure. Can also check circuit resistance comparing bank 1 to bank 2 for a "go/no-go" test to rule out possible ECM input circuit issues located at the 2 input resistors inside of ECM as shown below.

Thanks for giving this is a test. Out of curiosity, which ebay seller did you buy from?

My ES with 305k miles is throwing a knock sensor code, and I don't see myself buying OEM KS - thinking about doing the hack.

I bought fake KS from ebay for my RX300 back in 2016 (with a genuine toyota harness), and they are still going strong to this day but I can't find the seller name to get the same set again.

Received $100 junkyard ECU this morning and temporarily installed it for testing. Attempted the “30 minute OBDII immobilizer hack” but it didn’t work for me. I therefore paid a locksmith $120 to flash the eeprom since I didn’t want to wait for the Techstream software which I recently ordered. Upon flash completion I drove the vehicle for 45min and no CEL’s. Junkyard ECU appears to be happy with my temp knock sensors hanging from my temp brackets on the valve covers. This also suggests that bank 2 KS may be working inside the engine. I intend to remove my temp KS’s setup and re-connect old harness to verify if Bank 2 KS is actually working. If the old Bank 2 KS isn't throwing any codes, I’ll perform the Bobster Hack until I have a weekend to install both new sensors and sub harness. Then I’ll tear into my bad ECU and attempt to locate the failure…

Hi Crackberri, if you still haven't solved your problem check my recent post on how I did it.