Hi all,
I'm new to this forum and have recently purchased a 1991 4runner 5 speed with the 3.0 V6. While driving home the MIL came on and I found it was generating code 52, the dreaded knock sensor error. I purchased a new knock sensor (and a used one just in case) along with the pigtail that so often is the real problem. The pigtail is a genuine Toyota part. Not wanting to tear the intake off until I was sure the problem was diagnosed correctly, I mounted the sensor to the engine lift bracket as others and this forum have done. I installed it, cleared the code, took it for a ride, and it came back on within a quarter mile. I swapped the "new" sensor with the "used" one and still the same issue. I checked continuity from the sensor plug back to the ECM and everything seems fine. The new pigtail also tests good. Both new and used sensors generate an AC voltage with I connect a voltmeter and strike the sensor with a screwdriver. Being that they're piezo devices, it seems they're both good. However, I cannot figure out why it is not working.
I searched for "knock sensor" on this forum and have read all the related posts I can find. So what am I overlooking?
Thanks,
redwingz
I'm new to this forum and have recently purchased a 1991 4runner 5 speed with the 3.0 V6. While driving home the MIL came on and I found it was generating code 52, the dreaded knock sensor error. I purchased a new knock sensor (and a used one just in case) along with the pigtail that so often is the real problem. The pigtail is a genuine Toyota part. Not wanting to tear the intake off until I was sure the problem was diagnosed correctly, I mounted the sensor to the engine lift bracket as others and this forum have done. I installed it, cleared the code, took it for a ride, and it came back on within a quarter mile. I swapped the "new" sensor with the "used" one and still the same issue. I checked continuity from the sensor plug back to the ECM and everything seems fine. The new pigtail also tests good. Both new and used sensors generate an AC voltage with I connect a voltmeter and strike the sensor with a screwdriver. Being that they're piezo devices, it seems they're both good. However, I cannot figure out why it is not working.
I searched for "knock sensor" on this forum and have read all the related posts I can find. So what am I overlooking?
Thanks,
redwingz