What are knock sensors and how much do they cost to replace? - JeepForum.com
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > What are knock sensors and how much do they cost to replace?

The Cure for your Tie Rod Roll!Steering and more from Ruffstuff!Introducing MONSTALINER™ UV Permanent DIY Roll On Bed Line

Unread 11-11-2006, 06:38 PM   #1
Registered User
Join Date: Dec 2003
Posts: 608
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.

Gone: 97 Cherokee Sport
mdoug445 is offline   Reply With Quote Quick reply to this message
Unread 11-11-2006, 07:02 PM   #2
Registered User
2001 WJ 
Join Date: Aug 2005
Location: Memphis, TN
Posts: 3,218
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.
rm2001wj is offline   Reply With Quote Quick reply to this message

Quick Reply

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools

Suggested Threads

Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.