Code 52 Vanished
 

Hi everyone, looking forward to your input and continued worthwhile comments.
I first started reading these forums (yotatech) specifically, to find ideas and solutions to questions I had regarding my 91 Yota with its 3.0L V6. Most recent, has been an issue with my Knock Sensor CEL (code 52).
A little history. I had purchased this truck in Feb. and knew it had a bad head gasket. The dealership was asking more than I thought was reasonable to replace the gaskets on both sides. I elected to have the engine rebuilt and was pleased at having made that decision. The mechanic replaced the pig-tail and knock sensor at this time.
After driving the truck for a day or less, the CEL came on registering a Code 52. I reset the code and waited. The code came back on the following day.
I spoke with the mechanic several weeks ago and he said he would replace the KS which he had purchased from NAPA and thought it may possibly be defective.
The sensor was replaced last week. I asked him to drive the vehicle out to my house, about 30 mi. away and see if the sensor light stayed off. It did not, and came back on. He was at a loss and asked me to get a 2nd opinion as to the wiring from the ECM or possibly the ECM itself.
Here is the reason for this post!
Most of you having had the same issues may want to try my fix, well at least it has worked up to this point....I refueled with premium gas (before, using regular with 10% Ethanol)and reset my code. The code light has not come on since.
So, since this forum has been so helpful in answering my questions, my you find my information useful as well.

On a 24 year old rig the wires start to get brittle as well. It could be that even though you replaced the pigtail the existing wire where it connects to the new pig tail has a crack. Driving it could have jiggled it back in to a passable connection. Just a thought

Thanks fishguy for the incite. I failed to clarify that after the rebuild and subsequent CEL fiasco, I had thought of that and checked continuity from the pigtail connection back to the ECM.
Taking it one step further, I replaced the connection to the pigtail with one that I knew was working. When the issue resurfaced, the mechanic who did the rebuild focused on the KS and when that did not work, thought possibly there was another (ECM) issue.
Since putting in premium fuel, and reset the KS code, I have driven my vehicle over 200 miles with out the light coming on.

Code 52 is no signal, not a knocking signal. Interesting coincidence, but a coincidence nonetheless. Probably a bad connection or possibly the ECU capacitors, if it doesn't return soon then switch back to regular gas. There is a thread about this - https://www.yotatech.com/forums/f116...thread-216933/