1997 Jeep Wrangler failed smog test for bad oxygen sensor and check engine light on.

My Jeep Wrangler failed my smog the first time because of a bad o2 sensor and my check engine light came on during the test and my hc co% and ppm emission were all high also so i changed out my o2 sensor thinking it would fix that problem in lowering all my numbers and turn off my light well it did that but except my numbers were higher than before is there a reason why my numbers would do ok with a bad sensor then horrable with a new sensor?


Answer:		There is no saying why your Jeep Wrangler would fail the smog check with a new oxygen sensor. Perhaps there are other emission problems. The only way to be certain is to have a smog check repair center conduct a hands-on diagnosis. Your Jeep's smog check failure is odd considering it failed with a new sensor. We can only recommend a diagnosis. posted by SmogTips Support

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