knock sensor keeps triggering CEL - Toyota Nation Forum : Toyota Car and Truck Forums

91TurboMR2 · 01-16-2005, 11:01 PM

WTF!? I have just installed my second new knock sensor about a week ago. I have had to replace 2 so far but I contribute it to running higher boost without an upgraded intercooler. Any how, my problem is this. YEsterday and today when i went out and started my car and slowly drove away from the parking spot the check engine light has come on. I reset it yesterday and today after the engine warmed up and it doesn't come back. Did the cold do this???!!! I am getting frustrated with my mkII and I dont want to have to fork out another 165$ for a new knock sensor. 2 more sensors and I will have been able to buy a new intercooler for the $ I've spent on knock sensors! an help is great!

JekylandHyde · 01-17-2005, 05:31 AM

After you have installed the new knock sensor, have you been clearing the codes?
... if you did not clear the code, it remains there whether you installed a new sensor or not.

If you did clear the code, did you verify it by checking to make sure you have no codes stored?

***MRQtwinturbo*** · 01-17-2005, 12:01 PM

factory knock sensors are extremely fragile...i've gone thru about three of them over the years that i've owned the car.....i think the other alternative u have is getting an ATS one...its a bit cheaper than getting it from toyota.....

91TurboMR2 · 01-17-2005, 01:42 PM

I keep pulling the ecu fuse in the engine bay. I got a third CEL last night but I didn't get one today after I pulled the ecu fuse before i started driving it again. It only seems to come when its cold.

ya but the ats one is for a GM small block and I thought there was contreversy over whether those sensors read the right frequency range.

Is there any other things that can cause the engine to go into "limp mode" ? Becuase I have been assuming its the knock sensor that is to blame for everything and I haven't even done a check to see what codes are being thrown...... I wil look into it next time the CEL comes back to haunt me. Thanks alot for your help guys!

jason

JekylandHyde · 01-17-2005, 02:42 PM

Why would you assume it's the knock sensor if you never checked the codes?
It could be a lot of things.

Check the codes! ... it's free and takes 2 minutes to do.

If you are not pulling the correct fuse from the engine bay AND leaving it out long enough, you are not clearing the codes. Also, you do not have to have the check engine light ON to have a code stored.

To make sure you cleared codes, check the codes again.
If the check engine light flashes consistently (no pausing) then the codes are cleared.

1qckmr2 · 06-12-2005, 02:04 PM

try going to twosrus.com they have a gm knock sensor and pigtail adapter for like $80. the stock toyota knock sensor is weak and this gm sensor is so much stronger and the computer accepts it. i havent had any problems with it after i put that on my car.