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2001 Pontiac Montana Question: SES Light on with a code of P0420



Redrocker, Wilmington, OH, April 09, 2009, 06:52

SES is on with a code of p0420. I can clear it then it comes back on after a couple of days.

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  • Answer #1

    Bret Bodas from RepairPal Test Shop, April 09, 2009, 11:05

    check out this article on this code and what it mans: http://www.aa1car.com/library/p0420_dtc.htm

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  • Answer #2

    Visitor, April 10, 2010, 12:14

    Check for cracks near the o2 sensor near the exhaust manifold.

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