These codes turned on how much are they?
My car has 140 miles.
My car has an automatic transmission.
The P0155 is the oxygen sensor located on the rear bank of cylinders and before the catalytic converter. Given your mileage, both oxygen sensors (pre-catalytic converter) should be replaced. The pre-cat sensors have the most affect on fuel mixture, saving your catalytic converter from getting clogged.
The P1620 code indicates that the thermostat has failed. This unit uses an electrically heated element, which ages and will fail after a number of years.
If you haven't replaced your water pump yet, now would be a good time to do that while the cooling system is opened up. The original water pumps have a composite impeller (plastic) which ages, and will disintegrate without notice, overheating your engine in seconds. I would recommend an O2 sensor replacement service and a thermostat replacement service for these repairs. You can go to visit our estimator page to get a quote for these repairs.
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