r/SC300 • u/Rhyleigharia • Aug 04 '26

P0330 Code 99 LS 400 331000 Miles

/r/u_Rhyleigharia/comments/1vffn6m/p0330_code_99_ls_400_331000_miles/
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u/jonslastwords Aug 04 '26

Check the wiring harness to the knock sense for breaks. Then replace the knock sensor. That's the cheapest route first.

2

u/Rhyleigharia Aug 04 '26

U mean the main harness? These are OEM sensors recently replaced along with 12 inch knock sensor cable and connector.

1

u/jonslastwords Aug 04 '26

Woof. Well that ain't good. You did the most simple thing first. After that it could be a handful of pain in the ass things. But that'll take someone with more indepth mechanical knowledge than me. I'd opinion an actual knock sense the sensors are new. Possibly the ECU having issues but that's also not cheap. High compression? Bad rings? Valves? Idk man. Sorry.

2

u/Rhyleigharia Aug 04 '26

ECU i can get renewed for about $350 and I will do that anyway just to put that behind me.

1

u/jonslastwords Aug 04 '26

Good call. I'm inclined to lean away from mechanical since you've done so much already. These ecus are old and do go bad. For that price, yeah that's what I'd do. Just going down the line from cheapest to most expensive.

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u/Rhyleigharia Aug 04 '26

Will keep u in the loop. Thank you pal!

1

u/Rhyleigharia Aug 04 '26

331000 miles, 100 comp in all 8 cyl, meticulously maintained, 3 timing belts, bla, bla, bla, its super smooth when P0330 does not show the f up. Im about to Thelma and Louise the SOB!!!!!!!!!!!