Am I the only one plaqued by bad O2 sensors?

[Erin]

So on the way to work, the check engine light comes on for the 95 Corolla. Great, something to obsess over while trying to tick away the hours.

On the way home, the CEL came and went. Not flickering or rhythmically flashing., but just on for a while, off for a while.
I pulled codes and it was a code 27 – rear O2 sensor. GREAT. the harder one to get to AND it is more expensive.

Seems this happens on most of the cars I have owned where the CEL comes on – O2 sensor.
I don;t run anything crazy in the fuel system either.

Do O2 sensors just have this weird habit of going bad?

Topic

[James O’Hara]

O2 sensors have heaters in them. Over time they get plugged up with crap and the heater burns out. Then the sensor doesn’t read right and it goes bad. Additives as you already state you do not use can cause the sensors to fail prematurely. Over fueling can also cause them to fail prematurely. This can be caused by dirty MAF sensors and crap fuel causing sticky injectors. They can also fail from excessive oil consumption, coolant getting into the cylinders, and too much water in the fuel.

My guess would be wherever you have been getting fuel is not a major name like Sunoco, Shell, Exxon, or Mobile. But, O2 sensors all tend to go bad on vehicles any more. I blame the increase in ethanol which also means an increase in water.

[Jason White]

Well, it’s a 95 Corolla… no doubt it’s burning oil and coolant or just isn’t quite right, and that is probably some of the issue. Plus, those older cars had a lot of problems with O2’s and long story short, it’s probably an aftermarket O2.

[Ryan]

The computer cant always discern if a sensor is actually bad or if it’s a mechanical condition, and the computer is interpreting that condition based on the fact that a bad sensor can cause a similar problem. Say por ejemplo…O2 sensors are part of a long list of components utilized in the regulation of the air/fuel mixture. Well, a leaky vacuum hose can cause the air/fuel mixture to be off, usually in this case, a lean condition. The computer very likely will throw a code saying it’s an o2 sensor, when in fact, it’s not. BUT, the o2 sensor’s job is related to what the computer is interpreting the problem as. So you very possibly could be chasing the wrong gremlin. Often times I’ve seen where theres a hole popped in the exhaust and it’s sucking just enough air right before the o2 sensor, throwin a code suggesting an o2 sensor.

Food for thought. 🙂

[Author]

Replies