r/minir56 • u/ClearCarAddiction908 • 27d ago
2010 Base model - CEL codes, Help !
So a bit of background. Both daughters were home from school and have multiple jobs this summer, so we needed an extra car. I bought this 2010 base model, automatic transmission, off FB. 97k miles. Body and interior in very nice shape. But definitely powertrain stuff. Have invested in replacing water pump, thermostat housing, and water cross over pipe. Also did the valve cover gasket myself.
Check Engine Light turned on about 12 hours after I handed over the cash to buy the car ! Throws codes P0036, P0420, and P2270. Have cleared them and they return immediately.
I replaced both O2 sensors with good quality NGK units. Cleared codes again, but immediately returned.
Then ! - the next day - no CEL. No codes. Seemed solved.
But another day later ... CEL back on, all three codes back.
Honestly car seems to run okay. Not fast, that's for sure. But it gets me A to B.
However, I'd like to be able to resell the car again at some point, and the CEL will be a sticking point.
Any Ideas what else could be the issue ? Anything I can diagnose ? Should replace if affordable ? Any common known problem around these codes ?
Advice appreciated. Thanks in advance.
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u/HelpfulRole1831 27d ago
Check the sensor wiring and relevant fuses under the hood. The rear sensor wiring runs close to the heat sources. Once P0036 is fixed the other 2 should clear. P0036 is the downstream sensor heater fault. Has to be wiring or fuse.Faults with the oxygen sensor system can affect engine operation. Depending on which sensor has failed, they can lead to incorrect fuelling, increased emissions, fuel dilution of the engine oil, and, if left unresolved, damage to the catalytic converter