Dual Emission MIL codes - 0420 and 0137 - JeepForum.com

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post #1 of 3 Old 07-06-2013, 04:15 PM Thread Starter
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2004 KJ Liberty 
Join Date: Feb 2011
Location: Wethersfield
Posts: 10
Dual Emission MIL codes - 0420 and 0137

My wife's 2003 Lib's MIL light has been intermittent over the last week. I hooked it up and stored are the P0420 and P0137 codes. The dealer gave her a laundry list of items that would 'require' replacement to clear the codes but I was wondering what the more likely culprit would be from a more knowledgeable group.
Thanks in advance.

ETA: Stock. 115k miles. Normal fuel consumption. Local daily driver. Smooth idle. No smoke at startup or while driving.

Last edited by mu2bdriver; 07-06-2013 at 04:29 PM. Reason: Content
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post #2 of 3 Old 07-06-2013, 05:47 PM
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2005 KJ Liberty 
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Location: Castle Pines
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P0420, Bank 1 kitty cat is dirty and isn't working correctly or it thinks at least. Usually means B1 cat needs replacing, but I always verify before condemning. P0137, could be a symptom of a problem upstream with the engine running lean, or could be a faulty sensor. Hint, if you go to replace the O2 sensor, which I would consider before the Cat, do not, let me repeat DO NOT buy a bosch sensor. Use the OE, or an NTK(ngk) sensor.
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post #3 of 3 Old 07-08-2013, 10:44 AM Thread Starter
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