What are knock sensors and how much do they cost to replace? - JeepForum.com
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Unread 11-11-2006, 05:38 PM   #1
mdoug445
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What are knock sensors and how much do they cost to replace?

The 02 WJ i am looking at has two codes stored in the odometer when i do the key trick to get the codes. P0325 and P0330. These are codes for knock sensors on both banks. There is no check engine light or anything, the codes just show up on the odometer when i do the key trick. It seems to run great. Its the 4.7 HO. How much do they cost and how crucial are these things? I really want this jeep and need to know if i need to back out because of these sensors. What does a knock sensor do? Thanks.

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Unread 11-11-2006, 06:02 PM   #2
rm2001wj
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The knock sensors allows the HO to run well on gas octanes from 87 to 93. The engine will produce more power from 92-93 octane because of advanced timing. With failed knock sensors, I'm sure that the computer defaults to the low octane mode whether high octane is used or not. The parts cost of the sensors is probably not very much, but the intake manifold has to be pulled in order to get to them, and the labor could be kind of high. I would check with a Jeep dealership on the price of knock sensor replacements before buying.

Both of them going bad would be a bit unusual. It could be that they came unplugged during some kind of service like a spark plug change and not plugged back together or repaired. Look near the rear passenger side of the intake manifold to see if any connectors are loose or dangling.
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