O2 sensor

Jul 07, 2008 2 Replies

My friend has a 2005 Elantra which is running a little rough when she accelerates. I?ve check the OBD codes and the only thing tripping the computer is the O2 sensor. When I looked more into her car they have 2 O2 sensors, and the meter didn?t specify which one would be tripping the computer. So now I have a few questions.



first. Are there different symptoms for both of these 02 sensors to tell me which one is tripping the computer?



second. Would an O2 sensor really effect the acceleration enough to make the car stumble at times? Or should I start looking into bigger issues?


An 05 should still be under warranty if it has less than 60,000 miles. The 02 sensors may be under the emission warranty which is even longer.

The OBD code specifies which sensor's signal the ECM doesn't like, and it also specifies why the computer doesn't like it. What was the OBD code?

While it's possible for an upstream oxygen sensor to cause performance issues, that's very rare on Hyundai. Again, I'm curious to know the trouble code, but my gut instinct is that your performace issue is elsewhere, such as low fuel pressure or worn plugs/arcing wires.

The downstream oxygen sensor cannot cause performance problems. Its sole function is for the ECM to compare it's signal to the upstream sensor for the purpose of monitoring catalyst efficiency.

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