Your Volkswagen will pass a smog check if the oxygen sensor (O2) is bad. This exhaust system part is located at the front of the tailpipe and it measures the amount of oxygen found in your VW’s exhaust. Depending on the readings that it sends to the engine control module (ECM), the ECM may go ahead and adjust the amount of air or fuel in the combustion chamber. Eurozone Motors explains that if your oxygen sensor is bad, this mixture will be off. Here are signs that your VW needs a new oxygen sensor.
You End Up With a Check Engine Warning
One of the most common reasons why the check engine light turns on is that the oxygen sensor has gone bad. Because there is an imbalance in the air and fuel mixture in the combustion chamber, the ECM will turn on the check engine warning and it won’t turn it off until you replace the sensor.
Your Gas Mileage Suddenly Drops
Another sign that your O2 sensor is going bad is poor gas mileage. You won’t get as many miles out of each tank because the engine is burning excess fuel. This is a sign that there is too little air in the VW’s combustion chamber and you’ll find yourself going to the gas station more often.
You Smell Rotten Eggs
When there is too much fuel in the combustion chamber, it creates too many carbon gases and this can clog your VW’s catalytic converter. When this happens, you will smell rotten eggs in the engine and also in the exhaust. This is a sign of too much sulfur in the exhaust.
You’ve Got Black Exhaust Smoke
Another thing that will happen is that you will end up with black exhaust smoke coming out of your VW’s tailpipe. This is a sign that the engine is burning too much fuel, and this problem can be caused by a failing oxygen sensor. Replacing the O2 sensor should help.
Your VW Fails the Smog Check
Anytime your engine burns too much fuel, it releases too much carbon in the exhaust. This will cause your Volkswagen to fail the smog check. As you know, in California, you have to have your vehicle smog checked every two years and if it fails, you cannot register it.
The Engine Keeps Bucking and Sputtering
Finally, the oxygen sensor might be going bad if your engine is bucking or sputtering. Bucking or surging means that there is too much fuel in your VW’s engine. Sputtering is a sign that there is too much air and the engine is fuel-starved.
Stop by Eurozone Motors in Burbank, CA, for an oxygen sensor test. We can determine whether the sensor is going bad and if it is, we can replace it.