04 Acura TL
6 speed manual converted like 6 years ago
Been flawless, until last year when it randomly posted a knock sensor circuit code. I figured rodents ate the knock sensor wiring so I ordered a sub harness and knock sensor (standard brand) and replaced both. The wire wasn’t chewed but the sensor did break off when I attempted to unplug it.
Code returned after reassembly. As soon as I hit like 2000 rpm in second gear.
I tried another knock sensor, then a different brand, and eventually ordered one straight from Honda/Acura online and installed it. Torqued to spec each time.
I have verified continuity from KS plug to ECU pin. Inspected the engine harness and connections and note nothing of concern.
Live data (autel mk808bt) shows a knock related ignition value that changes around, as though it’s responding to knock signal. Another knock related reading seems to just stay in one spot and not move. I can’t remember the specifics, I would have to re run live data. It’s been months since I looked into it.
The ECU bounces back and forth between codes defined as sensor circuit malfunction and sensor signal implausible.
Just got the car back from letting a friend borrow it for a few months and now I’m back at it trying to figure it out. I inspected the ECU for any obvious swollen/leaking capacitors or other issues and it all seems okay.
Car runs fine. Doesn’t seem to have any glaring misfires or anything.
It does have poly motor mounts, full exhaust and a cold air intake, it was suggested that one or more of these could be causing resonance that the ECU interprets as knock and it doesn’t like it. But the car has been configured this way for as long as ive owned it both auto and manual and it’s had zero issues.
The code originally appeared after the car sat for a month or two not being driven, attached to a battery tender the whole time, hence why I assumed rodent activity.
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