Question about 1998 Jeep Cherokee

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I need to know what the definition for fault code

I need to know what the definition is for fault code PO 138 for my 1998 Jeep cherokee. I have the 4.0 L engine and an automatic transmission. The ''Check Engine'' light came on yesterday for no apparent reason.
What part will I need to buy or replace to correct this problem?

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P0138 is the O2 sensor (bank1 sensor2) has malfunctioned. Check the fuse box under the hood and look for a bad fuse and relay to the O2 sensor and also check the wire harness. Look for chrushed/broken clips from the O2 sensor to the frame harness. O2 sensor2 is the down stream sensor and should not have any performance problem to your engine, just a light on the dash. The O2 sensor that has gone bad is the down stream O2 which is the one after the Catalytic converter. A good spray of wd 40 and let it sit for 30 min before you try to remove it. You can use and O2 sensor socket, or a closed box wrench and a light hammer to break it free from the pipe. Good luck and hope this helps.

Posted on Jun 22, 2009

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The #2 O2 sensor on the cataylitic convertor,could be caused by a bad sensor or bad convertor.

Posted on Jun 22, 2009


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