O-2 sensor- How important is it? on 2003 Dodge Grand Caravan

The O-2 sensors wires were inadvertantly torn off by an inept mechanic while doing something else. He does not own up to doing it. Ive taken it to a muffler shop, but they couldn't get it out. It's way back behind the engine in the exhaust manifold and inaccessable. Looks like a lot of stuff would have to be removed (engine dropped?). Sure a dealership would charge arm and leg for. Car seems to run ok without. I'm told it will start to run rough, use lot of gas, damage engine etc. How important is it to repair? I know it continually adjusts carb to keep gas/oxygen ratio correct. If I understand correctly, the carb. stays set like it was at time it was made disfunctional. I've been thinking about not having it fixed. It seems to run fine.

by in Hot Springs National Park, AR on July 06, 2010
2 answers 3 comments
ANSWER by on July 06, 2010
The fuel injection computer needs this sensor to help determine the amount of fuel to inject into the engine, and if the sensor is disconnected you will have issues, perhaps small and unnoticeable at first but it will eventually turn on the check engine light on, and fuel mileage will suffer.
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COMMENT by on July 06, 2010
The engine light has been on for some time and I know it's because of the sensor not working. The gas mileage has not changed at all. It does seem to run fine. Can the engine get damaged?
COMMENT by on July 06, 2010
It's unlikely the engine will be damaged, but you can damage the catalytic converters, which is very expensive.
ANSWER by on July 06, 2010
sure it can get damaged. obd II has the ability to substitute a known good value to make the car run when there is a critical failure. it does not last forever and you will do further damage by not fixing it. why not persue your inept person and get it repaired. Roy
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COMMENT by on July 11, 2010
I took my van to our local dealership to have the O-2 sensor replaced. They gave me an estimate that blew me away. A min of $1200 to a max of $3000. The sensor is so corroded in the exhaust man. that the manifold needs to be replaced. They fear also that in removing the manifold, the studs into the engine block might/probably would break off. The car was from up north where a lot of salt was used and corroded everything. I refuse to put that much $ in a vehicle that's 8 years old. The mechanic at dealership said the carb. is set like it was when the sensor became disabled and will stay that way. I've been watching my gas mileage and its been averaging about 19 mpg, all around driving and we live in a hilly country. The mechanic said car should run okay for long while, but I may see some decrease in gas mileage. I calculated I'd have to drive car some 100,000 miles, assuming 3mpg less, to recoop the $3000. Not worth it.