how do u know when the catalyic converter is bad and is it hard to change also the 02 sensor, how do i know if that is also going bad
a cat is only a little bit more work than changing a muffler, the O2 sensors can be a bear, but if you are replacing the cat, then you only have to install new ones in the new cat.
BUT… what leads you to believe the cat is bad? why do you suspect this, and how have you determined this?
What code are you getting? And what make, model, options for your ride?
The best way is to run the car with an exhaust gas analyser, which is standard equipment in any shop that also does emissions testing. If the exhaust gasses are high in HCs and COs, then the catalytic converter is failing, and the 02 sensor is correct. If the HCs and COs are ultra-low, then the cat is fine, and the O2 sensor is failing.
well my car runs fine i just changed plugs and wires, my engine lite comes on and week later turns off
yesterday it took about 4 times to start my car up its happen before, its a dodge neon 2003 4cylinder
68000 miles, do u htink the fuel filter could be the problem, i want to take it to a shop but htey charge alot just to see what the engine lite problem is.is there anyway to test the battery ,starter and alternator with out removing it from the car …thanks for info
do you have an auto zone near you? they will read the codes for free (they are trying to get your parts business)
report the codes back here. DONT give the reason if your words, don’t summarize. give the exact codes.
the codes will read like, P0420 or something like that.
the check engine light being on is a BIG help, now just get the code(s) read.
hi there here are the codes
p0440
p0441
p0340
i went to auto zone and this is what they gave me, now if i went to a auto shop would they have the same results,even htough they charge 89.00 for the service…thanks jamie
Code P0440 - Evaporative Emission Control System Failure
Code P0441 - Evaporative Emission Control System Incorrect Purge Flow
Code P0340 - Crankshaft Position Sensor Circuit Malfunction
Non of these codes points to the catalytic converter or O2 sensors. What made you think that was what was wrong? The crank sensor problem will definitely lead to no-start problems. Chances are the connector is dirty or ware is damaged.
A bad oxygen sensor won’t affect starting at all.
is this something i can fix or do u recomend a mechanic, do u know the price for the crankshaft position sensor malfunction…thanks
hi there also i read in an artical that the pcm need to be fix whats a pcm
As noted P0340 is the likely no start problem. Check wiring and if that does not do it, replace it. If having it done it may be more economical to just replace it right off.
The other two relate to the vapor recovery system. They are likely unrelated. You might start by replacing your fuel cap. It may not be the problem, but it is cheap. Do you tend to top off your tank when getting gas. If so that is likely the cause of the problem, and now you will likely need a new charcoal canister, that may cost you a few dollars. 
If your unfamiliar with it, I’d get a mechanic. Some of these sensors are a simple replacement, and others require a proper adjustment. I don’t know how the one in your car is designed.
PCM - Programmable Control Module.
This is the main control module for the engine’s operation. It would be surprising if this was bad, and the CEL was not flashing. If the car starts and runs at all, I would not suspect the PCM itself to be the problem.
Will a bad o2 sensor make a funny noise on start up or when pressing on the accelerator, especially if it is cold/cold start up? I ask this because my shop cleaned my sensor last month, told me to drive it around and see if it drove better ( got more power to the engine), which it did. The funny noise in question has come back now, so I am assuming that I need to get my o2 sensor changed. I hope that makes sense.
i am curious as to how much an O2 sensor cleaning costs. how much did they charge you? O2 sensors have no moving parts. they usually don’t need cleaning. sometimes the wiring plugs get crudded up, and usually a unclipping, wiggling and reconnecting is all that is needed to get them to work again. but, they CAN go bad, and need replacement. a good mechanic shop can test them.
why do you think yours is bad? the noise is NOT coming from a O2 sensor.
The shop did it for free. As I didn’t explain clearly above the shop test drove my car, said it wasn’t getting much power to the engine, so they checked and cleaned the sensor and told me to drive it around and that should take care of the problem. It did feel better, accelerate faster for a while, but the funny noise is occuring again, which stopped immediately after they cleaned the o2 sensor. I checked my manual and the recommended repair or replace is 100k miles, my car has almost 125k miles, so I just figured it is time to change it. smog is due in september. Finally, what do you think is causing the funny noise?
hi there i have another code .P0344 Camshaft Position Sensor Circuit Intermittent
how i replace that and where is it located on my car i have a dodge neon 2003
you cant clean an O2 sensor,so b/s,go away. I think you need a hug,go ask you wife.
jamiefr, an o2 sensor has nothing to do with the starting ability of the car, does not/cannot make any noise, and any perceived performance gains are the effects of a placebo.
i don’t think your shop “cleaned” the o2 sensors so much as they have just bs’ed you a bit to send you on down the road.
if you have known problems with a car and present yourself to the shop as someone who does not want to spend any money in an effort to repair the problem; that right there may be why they bs’ed you down the road.
WHATS THE DIFFRENCE ON THESES CODES FOR A DODGE NEON 2003
I REPLACE THE CAMSHAFT SENSOR ,BUT WHAT IS THE OTHER PART FOR… ANY HELP