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I don't have a code from the computer just a part number but I think my real question is if I don't replace the oxygen sensor it won't hurt my car? I need to drive it a thousand miles first and then get the sensor but at $207 each I would only want to replace just the bad sensor? My jeep has the small engine.
Yes, you can (and probably should) replace just the one. Depending upon which one is bad, will depend upon how well your car car runs with it bad.
Modern cars have one (or 2) pre-cat and one (or 2) post-cat 02 sensors. The pre-cat sensors help the car determine how much fuel to deliver based upon operating conditions. If this one is bad, you might get too much or too little fuel that can cause drivability and other problems.
The post-cat sensor is generally to see how well your catalytic converter is working, and the car will usually drive fine without it. Some cars use the post cat sensor for a fuel other things (like communicating the cat is too hot and commanding some extra fuel to go through to cool it off improving emissions and prolonging the life of the cat) but I wouldn't worry too much about that for 1,000 miles.
OP the very first think you need to do is determine if you really do need an O2 sensor. what are the symptoms of what is going on? next you need to start with the basics, check for vacuum leaks, bad wiring connections, etc. after that you pull computer codes, and check the shop manual for the tests that need to be done for each code. start with the first code you get, and work through the list.
and remember, just because you get an O2 sensor code, does NOT mean the O2 sensor is the problem, it only tells you what system is being affected.
pre cat 02 sensors are the sensors that work with the computer along with other sensors that control fuel output. Post cat sensors monitor the efficiency of the catalytic converter(s). If the post cat 02 sensors fail or get lazy they won't affect fuel economy.
Someone else may confirm this but it was my understanding that the car runs fine with a bad O2 sensor, it's strictly an emissions thing.
Unnecessary increased pollution is not compatible with my definition of "runs fine."
With bad upstream oxygen sensor(s) the fuel mixture will not be continually optimized by the powertrain computer. This will compromise fuel mileage, emissions and throttle response and decrease the life of the catalytic converter. USUALLY the vehicle runs fairly well and some will not even notice.
In most cases, the downstream oxygen sensor(s) exist only to keep tabs on how healthy the catalytic converter is. (Some exceptions.)
Quote:
Originally Posted by DaveinMtAiry
You will have trouble passing your state emissions test though. Can I assume your check engine light comes on? If you can reset it can you tell how quickly it comes back on? One way to cheat the emissions testing system (so I'm told) is to go to an auto parts place that will lend you their diagnostics test, then you can re-set the codes. Drive it for a bit then get to the emissions center before the check engine light comes back on.
I think it makes more sense to have your vehicle running as well as possible as opposed to trying to get by with increased emissions.
pre cat 02 sensors are the sensors that work with the computer along with other sensors that control fuel output. Post cat sensors monitor the efficiency of the catalytic converter(s). If the post cat 02 sensors fail or get lazy they won't affect fuel economy.
Post cat. sensors do not effect fuel trim IN MOST CASES. There are exceptions.
Very rarely, do O2 sensors go bad. It is usually the catalytic convertor that is actually bad. This is one of the most commonly misdiagnosed codes on cars. If you don't have a scanner, go by Autozone and ask them to pull the codes for you. If you have P0420 or P0430, it is almost always the catalytic converter. P0420 is the driver's side and P0430 is the passenger's side. If you have a 4 cylinder or inline 6, you will only have P0420.
If you have other emissions codes, you may actually have a bad 02 sensor but we would need to know what code you have to help diagnose.
As others have stated, post cat sensors do not have any effect on the actual fuel trim or performance in most vehicles. They are simply there to detect catalytic converter inefficiency/failure.
My 1999 Prizm has been reporting P0420 codes for years. I have an OBD reader and I clear them when they show up. When it's emission testing time, I run some Chem Tool or other fuel cleaner in the tank for a couple of days to be sure, and have never failed a test.
You oblivious don't want to do both, so just do what you can afford right now!
Tell your mechanic you can only afford one right now, and that you will bring it back when the other one is bad.
If can afford to do both, do both for if not anything, peace of mind!
Quote:
Originally Posted by dijkstra
Very rarely, do O2 sensors go bad. It is usually the catalytic convertor that is actually bad. This is one of the most commonly misdiagnosed codes on cars. If you don't have a scanner, go by Autozone and ask them to pull the codes for you. If you have P0420 or P0430, it is almost always the catalytic converter. P0420 is the driver's side and P0430 is the passenger's side. If you have a 4 cylinder or inline 6, you will only have P0420.
If you have other emissions codes, you may actually have a bad 02 sensor but we would need to know what code you have to help diagnose.
As others have stated, post cat sensors do not have any effect on the actual fuel trim or performance in most vehicles. They are simply there to detect catalytic converter inefficiency/failure.
What this man said X10
Repped
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