I hate to keep beating this dead horse, but i have not been able to find an answer so... I get code 52... usualy after i get truckin down the road a mile or so, sometimes it comes on as soon as i throw her in gear. I changed the wire, and still get the code..i know i need to do some soldering and such to the other end of the wire..my question is, if i disconnect the sensor all together shouldnt my cel come on after 3 sec? would it indicate a faulty ecu if it does not come on till i get down the road? Thanks

 

doesn't anybody have an idea?? Or is everyone just sick of answering knock sensor questions.. im at the end of my rope with this thing.. i soldered the wires up real good to no avail.. still does the same thing, makes no difference if the harness is connected or not!!

 

I know its rare but maybe you need to replace the sensor itself ??? I have been having knock sensor issues myself that I have yet to figure out.

 

thats what im startin to think... but i dont wanna spend $180 on a sensor if its not gonna work... i just wanna know if its normal that the cel dont come on till i get down the road a bit, even if the sensor is not connected, doesnt make sense, does it not listen for knock at idle? i can let it idle for an hour, still no light...once i get a mile or 2 down the road..it pops on...makes no diff if the sensor is hooked up or not.

 

Generally, it's hard for KS to go bad.. Now I know this is a common issue on the3 3.0 trucks - so you might search or wait for some feedback.

There seems to be "test circuitry" that validates that the sensor is connected. Disconnecting it won't solve your problem.

There is no knock at idle. It's generally an under-load condition.

 

My cel comes on at about 3000 rpm every time ??????

 

have you changed your wire yet?
thats what mine usually does...only when under load tho, i can rev to 4,000 rpm in neutral and it doesnt come on..in my case; my harness(ecu side) looks nasty, and the wires pull out easily, hoping dirtoyboy can hook me up with a new one, and that it'll fix my prob, .... if not..guess ill b gettin in there AGAIN to change the sensor(prob should have done that to begin with!!!)

 

toyota ECU's don't use the knock sensor until after 3000 RPMs. You sensor could be putting out crap and the ECU won't know until the truck revs to 3K.

 

ok...thank you.. that answers my question.. although my cel usually comes on long before 3k.. i try no to get it up that high when accelerating..And now i have another question.. tonight i get into my truck and the cel comes on at startup... pulled the code got 71..egr gas temp.. at first i would think this is normal from the high egt's, however in the haynes it says this code is for gas temps being low, or a bad temp sensor... coincidence? or did i misunderstand the effects of knock retard? it was my understanding that retarded timing = high egt's

 

do these symptoms sound like an ecu problem...im startin to get real confused about all this

 

What exactly does a knock sensor do? I don't believe mine is hooked up on my truck lol.

Rob

 

It "listens" for engine knock, and retards timing, to correct it... it is fairly important, and if not working your truck will run in "safe mode" ... thus retarding your timing to zero = less power, decreased fuel economy(in my case drastic), and higher egt's which can lead to other problems.