Knock Sensor

[PowderBrad]

Hey Guys

Started sled up and the check engine light is throwing a 2-1 code. Looked it up and the forum says its a knock sensor failure.

Just need to know what could be causing this. Any ideas?

Dont wanna take to dealer if I dont have to. Anythign i should look at. Sled may have got a little warm riding out to the truck last year with no coolant (hole in heat exchanger). Dont know if its in limp mode or anything seeing as its summer.

Thanks,

 

[RACINSTATION]

21 is the knock sensor failure code. Usually only goes off when the sensor is detecting detonation.

I would wager a guess that the knock sensor has failed because of lack of coolant in the machine. The head has gotten extremely hot and damaged the sensor. You can unplug your ECU, plug back in and start machine again. Once you shut it off it should clear all the codes and start fresh with each startup. The ECU does retain failure codes until cleared with the CATT tool at a dealership.

 

[hatchers]

the knock sensor AC uses is not too far from a the cheapest POS made possible.....mine goes off anytime i go above 14ish lbs....my sled is running great and the 0/2 is at 12.5......i know a few who have simply installed this sensor on the fuel tank heat shield...

 

[ProCat]

fix?

any luck fixing your code 21?
By the way, it codes 23 if its going off and doing its job however code 21 indicates the sensor has failed

 

[ItDoAble]

Did the same with mine last year .. cracked the coolent line under the tunnel and got very hot. Learned the hard way that the stock WT gage does not register with no coolent on it.

Had to replace the deto sensor (21 code).

Also check the rubber o-rings on the head bolts and the pistons. If the sensor got hot enough to do damage, the o-rings may be compromised.

I had to do a complete top end. And put in a Koso WT gage with sensor in the bottom coolent line coming out of the engine (because I'm a paranoid SOB).