Downstream Oxygen Sensor - Pontiac G8 Forum: G8 Forums -
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post #1 of 5 (permalink) Old 01-28-2016, 10:42 PM Thread Starter
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Downstream Oxygen Sensor

I ran over a small piece of lumber at night and it hit the underside a few times. After I parked and turned the engine back on, the check engine light goes on. I plug in my scanner to find it is heater downstream driver side error code. I then jack it up and look under to find everything ok but there is a small dent on drivers side downstream sensor. I buy a cheap new downstream sensor on ebay and install it, clear the error code and it works fine but in two days, the error code comes back. I have erased the error code again but after a few days, it is back. Any ideas? the wiring harness to the sensor does not appear damaged. Did I maybe buy too cheap of a sensor? It fit perfectly but was only $25. Do I have to buy AC Delco or Denso brand sensor? Maybe I will switch sensors and see if computer throws error code for passenger side.
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post #2 of 5 (permalink) Old 01-29-2016, 07:25 AM
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With those sorts of parts I always get OEM, 02's, thermostats, gaskets that sort of stuff.
If an OEM part doesn't fix it then it (the wood) may have pulled on the wiring.
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post #3 of 5 (permalink) Old 01-29-2016, 08:15 AM
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I agree with Nick Ash -- always OEM (ACDelco) when it comes to electronics, seals, etc. Check Amazon and Rock Auto -- they usually have the best prices.

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post #4 of 5 (permalink) Old 01-29-2016, 09:11 AM
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I tried 4 Denso o2 sensors before I got smart and bought an AC Delco sensor. No more issues.

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post #5 of 5 (permalink) Old 02-03-2016, 01:13 AM Thread Starter
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I switched the sensors and found my theory to be true. The error changed from driver to passenger side so it is the sensor and the not wires leading to the sensor. I will order AC Delco sensor and that should fix it. Lesson learned. Do not use cheap ebay downstream sensor or the check engine light will forever luminate.
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