Hi all,

Recently, my knock sensor was going bad, with CEL P0330 on. I investigated this issue, and finally decided to replace it., as I will have long trip in the future.

I purchased genuine Toyota parts from Ebay and asked local Toyota dealer to install it. They gave me a quote of $425, I think it is good for me. The next day, I sent my car to the dealer , then the thing happened.

The service manager initially told me that the car would be ready at 12:00 PM, but at 12:00 PM he called me it has to be put off. Then he continually called me that the engine is leaking and need $1000 to repair. I denied because I check my engine oil level regularly and everytime the level is OK. If there is a leak, the leak must be too small.

At 3:50 PM (they already spent 7 hours on replacing it), the service manager called me that I need a new ECU. I didn't trust him because I know ECU rarely going bad. I thought he just fool on me, the car should be done properly.

I went back to the dealer, and service manager showed me a diagnose paper, and told me that the car still got P0330. I checked my car, yes, CEL is on and P0330. I didn't argue with him, just want my car back. He told me I have to pay for the service, then I paid. No choice for me.

In the invoice paper, it says:

Replaced knock sensor and wire harness, replaced intake gaskets and coolant. Road test the check engine light come back on, code P0330- Knock sensor 2 circuit malfunction. (Disconnect EA1 connector and Check Open and Short there was good and continue wires ok, Bad ECU)


When I got my car back, I spent 15 mins on hacking knock sensor (great thanks for the instruction), the CEL never came back for 100 miles and 7 days now.


The next step is how to argue with dealer. I am not sure if the hacking method is enough to proof the ECU is good. Need suggestion. Thanks all!

 

I hope you can see my post in the right light ..

So you contracted the dealership to replace knock sensors and provided them with the knock sensor. Did they do what you asked? Part of your note seems to convey that they did and the other part is they did not.

Lets go with the scenario that they did replace the parts:
If you yourself were to do the above task and your check engine light was still on, what would you think? Maybe the part(s) were bad? Maybe the work was not done right? Maybe the ecu is bad?

If the parts were not replaced:
That is something to get upset about. But how do you find out?

A better situation would have been if you had gone to Lexus and with error code and asked them to make the repairs. It may have been the same situation but if they had to rework the sensors, that would have been on them.

You can ask the dealer to scope the signal out of the sensors. They or you can swap out the ecu. After confirming right behavior you can invest time and energy into personalizing the ecu.

Salim

 

There are 2 knock sensors, one for each bank. Are you sure they replaced the bank 2 knock sensor and not the bank 1 sensor with the one you intended for bank 2? Or as you suspect, maybe didn't replace either one? If I had a nickel for every incompetent mechanic there is, I wouldn't be rich, but I'd have a HUGE pile of nickels!

 

i rarely ask for a specific repair shop name because it is too easy for a competitor to make up a problem and flame someone unfairly. however, you indicate you are from wisconsin, as am i. can you at least tell me in which city this dealer is located?? again, i don't need the name.

 

Or one of the sensor is bad.

Salim

 

Salim, the P0330 DTC points to bank 2 knock sensor. That's why I said what I did. That's the code they got before the replacement as well as after, that's why I wondered if they replaced the correct one, if indeed it was replaced. There was no indication of P032X DTC's which would have been the #1 bank. Having spent my life in automotive work, I'm truly embarrassed at the dishonestly and incompetence in automotive repair. Hats off to those who DON'T fit in that category.

 

i recently got engine light which also shows knock sensor but its bank 1. The first time it was on i erased it but in like 2 weeks it came back on. Then again after some time i erased it but then it came back on after like week or so. Then it went off automatically after a few hours. It has be intermittent like this. I know that its expensive and labour intensive so i am not going to go ahead and change for now. Plus its not affecting mpg or performance.

 

There is a possibility that the new sensor that was installed (assuming it was installed) was bad.

Salim

 

That is exactly how it started for me. At the end it is not how you feel, but how the ecu is adjusting based based on all the information it gets. By waiting around it will not go away on its own. Parts and labor will keep going up and if you intend to keep the RX, get it fixed at your convenience.

Salim

 

I am sorry. I forgot to inform that I actually replaced two knock sensors, not one.

I am currently at San Jose ,CA, and did replacement there.

I think they did the replacement. for the reason that previously, the CEL came out occasionally. After I cleared it, it required a long period to came back, since my car is always feed with Shell Premium gas. Now, after I clear clear the CEL, it requires only 1 miles driving to came back. My guess is that, previously, I had a weak sensor, and now I had a completely bad sensor.

 

As Salim said, it could have been damaged along the way, either in transit or in the install process.
Did you replace both sensors because it was only wise to do it while they were in there or was there another reason? Full details are important from the beginning, as you can see from logically assuming that one sensor was replaced because the DTC was for a specific sensor and there was no mention of a 2nd sensor. Wish I could say I trusted mechanics but I'd be lying to you. Again, apologies to those that are honest and competent. Just not NEAR enough of you!
I have helped many who have spent their money and still have the problem, and no, I DO NOT charge!

 

Yes, i thought it was wise to replace both together. i read the Salim’s posts, and decided to replace both sensors to avoid replacing another in the short future.

There was only p0330 came out.

As I purchased genuine Toyota parts, the ebay seller has already guarantee to honor the warranty, once the proof of bad parts is achieved.

I just don’t know how to deal with the dealer, if they insist to say it is ECU’s problem.


I sincerely thank you all for your kind help.

 

The only ways to make sure the sensors are producing the right signal are:

1. Replace the current ECU with a good ecu.
2. Replace the sensor with a good one .... If is was easy, I would say swap the two sensors and see if the error code moves to the other bank.

3. Scope the signals. See if you can get an oscilloscope or equivalent and see what electrical signals you get at the input of the ecu. Try to compare the wave shapes of the good bank vs the bad bank sensor..

The dc (ohm) check the dealership did only checks for electrical connectivity and expected resistance of the sensor. The knock sensor is a like a microphone.

You can also try to work with the dealership to swap and test out the ecu. If it does not fix the problem then the dealership takes the ecu back and if it solves your problem then you part with $$$ and the aggravation of reprogramming.

.Salim

 

Hi salim, I really don't understand why, by slicing (hacking) from the good knock sensor stops CEL come back can not proof that the ECU is good and knock sensor is bad?

Assuming ECU is bad, then no matter what kind of signal is input to ECU, CEL should be light on all the time. But now, when I give (slice) the signal from the good knock sensor, the CEL is off. I think that is enough to show that ECU is able to recognize the good signal, and then the only bad part is that knock sensor.

Am I right?

 

For me to make that call, I need to know exactly how the system works. Details such as when the sensor input is sampled. When a dummy input is supplied, the timing is not synchronized with the ignition (of the right bank). Think if the input from bank one is supplied to the bank2 input of the ecu would you get a CEL?

If you are convinced that the ecu is indeed good, let the dealership test swap. This would require a level of trust. You can buy a used ecu and test it out yourself.

Your options are swap test (ecu or the sensor).
Diagnose by electronic equipment. <= Scientific approach which may require some technical know how and access to oscilloscope.

Salim