02 accent, 1.6L. had some problems in last 2 years with this car, almost none the first 10 years except trying to put gas in it. anyway i'd say 75% of parts under the hood are new. right now it sputters mainly in park or drive at a stop. it seems to accelerate fine and cruises fine. check engine light comes on sometimes then goes back off. had it checked about 6 months age (check engine light) and code was for coolant temp sending unit. anybody know if this would be the problem. i'm thinking it might be catalytic convertor (130000 miles on it). anybody on here ever had to replace it and what were the symptoms? thanks

 

My guess would be a vacuum leak but I would suggest maybe taking it to the dealer or a trusted mechanic for diagnosis because it could very well be a cat. As for the CEL reading, I would not understand how the coolant temp sending unit would cause the vehicle to sputter.

 

First things first: check for vacuum leaks (Youtube, any car).
check fuel pressure
check the plugs and coils
Some cars have 2 separate coolant temperature sensors: a cheap one for the dash that has no effect on driveability and a better one that informs the computer. Other cars have only one that supplies both. If that second one (or the only one) is faulty then the computer gets junk for data and that can and will cause trouble.

 

coils, wires and plugs are 1 year old. I will check for vacuum leaks and get that check engine code again to be sure. thanks

 

Could it be the purge control valve or solenoid purge valve?

If you suspect a clogged cat then maybe removing the up stream O2 sensor can help test if the engine runs better with another way for the exhaust to vent

A coolant temp sensor lets the ECU know what the temp of the engine is and how much fuel to dispense through the fuel injectors accordingly
If the reading is wrong then it can inject too much or too little for those conditions it does not see

 

well check engine light came on again and codes were for cyl. 1 misfire and for TCM (transmission control module), WTF. last time code was for temp coolant sensor as I said in an earlier post. I been trying to remove o2 sensor to see if that helps since I suspect maybe cat. convertor is clogging up. cant get it off yet with o2 socket, think I need a breaker bar, seems nothing is ever easy to work on this damn car. I had a dodge spirit years ago and when the cat convertor plugged up it sent the computer haywire telling me I had 5 or 6 bad sensors, which my dumbass replaced to no avail! anyway the coils plugs and wires are all 1 year old and it shifts fine, what the hell does a TCM do anyway and where is it? thanks

 

I believe that the TCM for your vehicle is part number 95440-22950 (if you end up needing it, we have it for sale here: CONTROL MODULE - AUTOMATIC TRANSMISSION ASSEMBLY made by Hyundai. #9544022950) and there is a related TSB which I have attached. Unfortunately my diagrams do not provide me with a location. The TSB offers some photos that lead me to believe that the part is under the dash somewhere.

 

You may not need to remove the HO2 sensor to diagnose a clogged catalytic converter. The easiest is using a temperature probe and take a reading directly before and directly after the converter. A functioning converter will have a higher temperature after the cat.

Another way is drilling a hole in the exhaust pipe and bolt in a transducer to take a pressure reading. The hole can be plugged with a bolt.

Youtube has a number of videos explaining the processes.

 

It is the upstream O2 sensor right after the exhaust from the engine and before the cat and should be under the hood.
It should be easy to get to and not as difficult to get off as the one under the car.
I have changed my O2 sensor but I needed to put an oxy-acetylene torch on it. And even then it wouldn't come out easy. The threads were gone .. pipe wrench and long pipe.

The Transmission Control Module controls the gearbox and determines how fast the vehicle is moving and what gear it should be in
It also determines if there is a problem with the transmission and can put the transmission in "LIMP HOME MODE".
An ordinary scanner may not work to read the TCM codes.

 

Try with a wrench if you have one its a 22 for the O2 sensor on the exhaust pipe. My guess would be more towards the fuel injectors if you have a misfire code. try some injector cleaner in your gas tank with some high grade fuel. You might need to change an injector if there is nothing wrong with the wires along the fuel rail and you're tune up is done. To follow on what avisitor was saying about the evaporative recirculation lines and purge valves. There is a recall for these cars on the recirculation hoses and throttle body temp sensor. when it gets really cold the gasses freeze up and cause problems. Could also be timing adjustments or timing belt if it hasn't been done in a long time if ever. Have a look at the service manual for recommended maintenance.