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C300 overheats

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Old Sep 26, 2021 | 10:32 PM
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c300 4matic
C300 overheats

Hello everyone I installed catless downpipe today and tuned it. After tune the car my CEL light came on, shop said to buy o2 sensor. Would that be the reason my car starts to overheat a bit? Would to know some feedback from anyone who’s staged 2 I’m a beginner at this
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Old Sep 27, 2021 | 01:45 PM
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2018 C43
Curious, what do you think would happen when pollutants passes catless cat and existing o2 sensor pick this up and complains to the ECU? You would get a CEL.

When you install a catless dp, your tuner needs to disable the CEL from o2 sensor. Installing another o2 sensor will just trigger CEL. This is why lot of people upgrade to catted dp, but even then ECU is picky when O2 sensor gives it's readings. So you would need to tune it regardless.
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Old Sep 28, 2021 | 09:39 AM
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W205 2015
Your tunner should fix the issue. What if you bought another O2 sensor and the issue remains. Why the car overheating.
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Old Sep 28, 2021 | 02:11 PM
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c300 4matic
Originally Posted by stockbmw
Curious, what do you think would happen when pollutants passes catless cat and existing o2 sensor pick this up and complains to the ECU? You would get a CEL.

When you install a catless dp, your tuner needs to disable the CEL from o2 sensor. Installing another o2 sensor will just trigger CEL. This is why lot of people upgrade to catted dp, but even then ECU is picky when O2 sensor gives it's readings. So you would need to tune it regardless.

According to tuner my o2 sensor was scaled and not completely shut off. Appreciate your guys replies and help
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