otto_crystal1
Mercedes CLK O2 Sensor Issue
Summary of the thread
A 2004 Mercedes CLK owner experienced a check engine light and increased fuel consumption, suspecting a faulty O2 sensor or connection. The issue was likely due to a corroded connector affecting the sensor's data transmission. After cleaning the connector at a garage, the check engine light was resolved, and fuel consumption returned to normal, avoiding potential damage to the catalytic converter.
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4 comment(s)
otto_crystal1 (community.author)
No, the engine seems to be running smoothly, which is why I suspected the connection first. If the engine was running rough, I'd immediately jump to a mixture problem caused by the sensor itself. Given that it's running smoothly, could a faulty connection still cause the increased fuel consumption and the check engine light?
jenniferdragon1
Yes, a faulty connection could absolutely cause those issues even if the engine runs smooth. The computer is getting bad data from the sensor. I would suggest taking it to a workshop, so they can read the data. You can probably get away with 95€.
otto_crystal1 (community.author)
Thanks for the insight! I had the O2 sensor and its connection checked at a local garage. Turns out you were spot on it was a corroded connector. They cleaned it, the check engine light is gone, and the fuel consumption seems back to normal. Much appreciated!
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MERCEDES
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CLK
jenniferdragon1
It could be the O2 sensor. Is the car running rough? Sometimes a bad sensor throws off the fuel mixture and you'll notice that. It's like when a recipe calls for a teaspoon of salt, but you accidentally dump in a tablespoon.