SENTRA 1.8 2001 knocks when temp reads normal.

[maik21]

hello , my brother has a 2001 sentra 1.8 with qg18de that knocks when car reads normal temp. car uses 89 and 93 octane and problem dont go.

no check engine lights, so my brother think knock sensor is damaged. i will apreciate some help from u because this sensor its about 220usd in my city.

thankyou !!