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Ask Chris (aka-Moose) Your Own Question
Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Car
Satisfied Customers: 1044
Experience:  16 years of experience
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my check engine light stays on even though i had oxygen sensor

Customer Question

my check engine light stays on even though i had oxygen sensor replaced vehicle failed emmissions test code po420. 2002 s 10 pick-up 4 cyl 2.2l eng.
Submitted: 3 years ago.
Category: Car
Expert:  K. Wiggins replied 3 years ago.
Hello, there are other things than just a bad downstream O2 sensor that can cause this. Wiring going to the sensor, exhaust leaks before the sensor and even a legitimately bad catalytic converter.

Did the shop that replace the sensor offer an other information on why they replaced it? Did they mention anything regarding the live data reading of the output voltage of the sensor?
Customer: replied 3 years ago.

please cancel my request