Asked by: Meggan Natschke
asked in category: General Last Updated: 2nd May, 2020

How do I know if my upstream or downstream oxygen sensor is bad?

Symptoms of a Bad or Failing Oxygen Sensor
Reduced gas mileage. A bad smell like rotten eggs coming from the exhaust. The check engine light comes on. You notice that your engine idles roughly.

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Also asked, how do I know if I need an upstream or downstream oxygen sensor?

The upstream oxygen sensor is situated before the catalytic converter whereas the downstream oxygen sensor is located after the catalytic converter. Knowing the location of the oxygen sensor at fault is important. The number and location of the oxygen sensors are specific to every vehicle's year, make and model.

Also Know, can you use a downstream oxygen sensor for upstream? A downstream oxygen sensor in or behind the catalytic converter works exactly the same as an upstream O2 sensor in the exhaust manifold. The sensor produces a voltage that changes when the amount of unburned oxygen in the exhaust changes. On some newer vehicles, a new type of wide ratio air fuel sensor is used.

In this manner, what are the symptoms of a bad downstream o2 sensor?

The downstream or diagnostic sensors only monitor the exhaust leaving the catalytic converter and will not cause such an issue. Other symptoms of a bad oxygen sensor include a rough idle, a misfire, and/ or hesitation when trying to accelerate.

How do I know if I have a bad o2 sensor or catalytic converter?

Signs that you may need a new catalytic converter include:

  1. Your car throws a check engine light.
  2. Your engine misfires.
  3. Your car noticeably uses more fuel.
  4. Your car isn't performing the way it used to.
  5. Your car fails an emissions test or it has more emissions than normal.

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