I have the top end open on my truck should I replace the knock sensor under the manifold or leave alone

 

change the pigtail. the knock sensor is about 300 bucks, and they are pretty much impossible to fail unless its physically damaged. The wire however gets brittle over time from heat, i bought one form the dealership for 23 bucks.

 

Yes, replace the pigtail, leave the sensor itself alone (unless you know it's bad, but you wouldn't be asking this question, then, would you?)

 

I would replace it. Shop around online for one. U would hate yourself for buttoning ur motor up just to get a code 52.....

 

Code 52 resukting from the knock sensor itself is a very very slim chance. The only time thise sensors break is whem they physically get broken by being smashed or someone trying to take it off. Read up on it. Research the type of sensor it is. They are not subjected to coolant or oil, they shake and they are deisgned to be shaken.

 

If you are in there, and ave the means to change both the sensor, and the pigtail.. DO IT!! lol.

I had cel code 52 for over a year... finally got fed up with it and tore it down, and replaced just the pigtail... still code 52... After re-wiring the pigtail directly to the ecu, still had code 52. Finally, after another year, I decided to replace my valve cover gaskets, and the knock sensor wile I was in there....... NO MORE CEL!!

I'm still not sure if it was the vacuum leak from the vc gaskets, or the knock sensor itself that was causing the issue, (even tho some will argue with me till blue in the face that it had NOTHING to do with the vacuum leak) I would say replace it while your in there. Its not terrribly difficult to get to, but is time consuming, and a real P.I.T.A when you know you coulda just done it when you already had her open....