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internal88, Technician
Category: Hyundai
Satisfied Customers: 2560
Experience:  Over 10 years in the Import Auto industry. Engineering background and diagnostic is my specialty.
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I have a 03 hyundai santa fe. I started it this morning and

Customer Question

I have a 03 hyundai santa fe. I started it this morning and it shut off on its own and now wont start. When I turn it over im getting a gas I put my scan tool on it and im getting a PO421 code warm up cat efficiency below threshold. Please help
Submitted: 1 year ago.
Category: Hyundai
Expert:  internal88 replied 1 year ago.

Hello, I'm Brandon - Hyundai tech.

This is a common code for us at the dealer.

It is either the exhaust manifold is cracked or the cat converter is bad.

Expert:  internal88 replied 1 year ago.

A lot of time we see a small crack in the manifold which cause the damaged of the converter. Therefore we replaced both components and all it's fixed.

Please rate me positive to support the U.S tech. Thank you!

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