Knock Sensors

[devin_deville]

I hooked up the scan tool today, and it showed two codes, Knock Sensor 1&2 Circuit Low Frequency. How am i supposed to fix this? What could cause this?

[farmtruc]

It's pretty common for these knock sensors to get messed up from moisture.
I would remove the intake manifold, replace the knock sensors and small harness.
Only way to do it.

[RedHeartbeat]

It's pretty common for these knock sensors to get messed up from moisture.
I would remove the intake manifold, replace the knock sensors and small harness.
Only way to do it.

+1

Also remove the foam pieces under the intake and build a half moon crescent shape wall of silicone in front of each of the knock sensor seals, piling it onto the aluminum valley pan cover.

[jcormier89]

yup...i had to do that about 3 months ago

[GasGuzzler]

Yep. Two sensors, one harness (if brittle), intake gaskets (if the old style or high miles), remove the dams from the intake, and seal the FRONT HALVES of the valley grommets with silicone.

[CHEVROLADE]

its easy,just replaced some on my 03'yukon and buddys 02'2500 hd last week.1 1/2 hour job

remove intake,get ready to clean up a mess under there too.cover the cyl head ports before you clean it.and yes when you install the new ones,put some silicone around the seals that cover the sensors.

[gTeran1]

what do the Knock Sensor do?

[zeake]

what do the Knock Sensor do?

It listens for knock. Very important sensor. It helps the computer to know how to change timing to get rid of knock.

I am sure someone better with words and technical terms can give a better account of what they do.

[CHEVROLADE]

can u delete knock sensors like the 02's??lol probably dumb question.

[zeake]

can u delete knock sensors like the 02's??lol probably dumb question.

You would not want to do that.