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Q: My car failed the smog test and two codes came up: P0422 and P0432 Both Catalyst 2 Efficiency Below Threshold Bank 1 and Bank 2.

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Can the catalytic converters be repaired or do they have to be replaced? How much would it cost? Who can make the repair other than the dealer? I am worried the cost is more than what the car is worth.

My car has 249000 miles.
My car has an automatic transmission.

A: Hello there, thank you for asking about you...

Hello there, thank you for asking about your 2003 Mercedes-Benz ML350.

The catalytic converters have to be replaced. You have 4 options for parts and labor: 1. Have a certified technician from YourMechanic come to your home or office to replace your catalytic converter. This service includes both parts and labor. 2. Buy the parts from Mercedes-Benz. This will include a length of pipe, for the left and the right, that have 2 converters each. Have Mercedes-Benz give you a quote for the whole job. You could also buy Mercedes parts and call around shops to get a quote for installation. 3. Aftermarket replacements are available to buy that are specific to your car and will be less expensive than the parts form Mercedes-Benz. You can call local auto shops to get a quote for installation. 4. Have a muffler shop cut out the old converters and weld in new ones.

If you choose to go to an auto repair shop, find one that specializes in German cars. You can also have a technician from YourMechanic who is specialized in German cars come make the replacement.

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