Both of these codes are saying the same thing. They are saying that the emissions measured by the o2 sensors is higher than the spec and it throws the code. This could be by three main reasons.
1. The converter is not reacting with the hydrocarbons in the exhaust and it is passing to much through to the atmosphere.
2. The downstream sensor is faulty and reading higher or more hydrocarbons then are there.
3. The upstream o2 sensor is reading lower or less hydrocarbons then what the downstream is reading.
The PCM is looking at the difference between the upstream and down stream sensor. When that difference is not correct then it sets the code for below threshold.
Assuming you have good parts that you replaced, I suspect you have an exhaust leak that is allowing air in and exhaust out. This is throwing off the measurement that these sensors are taking. They need to have a sealed system so that they can measure accurately.
Usually, the non welding converters come with a gasket and if you don't get them tight enough they will leak and you will have to most likely replace the gasket again and try to tighten them to ensure no leaks.
The easiest way you can tell if they are leaking is putting your hand around the joints/connection points of the exhaust with the engine running and see if you can feel exhaust pulses. You should not feel any pulses. Be careful not to touch the exhaust as it gets hot quickly.
Let me know what you find and we can go from there. Thanks
Thursday, June 6th, 2019 AT 2:12 PM