Service Engine Light after new cat installed

spider_0072spider_0072 Member Posts: 4
edited April 2014 in Pontiac
I have a 2001 grand prix GT that was having acceleration issue and I determined that it was a catalytic converter issue. The service engine soon light never came on. I just had a magnaflow direct fit, catalytic converter installed and the problem was fixed. The next day the service engine soon light came on. I haven't had the codes read yet but I was wondering if anyone else has had a similar issue with this after installing this or any other brand of converter. I am going tomorrow to have the codes read but wanted to know if this is caused by installing the new converter. Can I clear the codes and not worry about it? Any insight would be much appreciated.


  • cobaltblue1cobaltblue1 Member Posts: 2
    You may want to look at the Mass airflow sensor. When the SES light comes on it generally refers to an eviromental problem -O2 sensor, Gas cap not sealing, MAF sensor and so-forth.

    Go to an autoparts dealer that will do an OBDII check for free. That should determine the problem.

    BTW, it's easy to change out the MAF sensor but you will need a special Toax screwdriver. Price is a little steep.

  • cobaltblue1cobaltblue1 Member Posts: 2
    Does anyone know if I can replace the bulbs in the running lights and change the switch on the dash to have OEM fog lights. I don't have the service manual to look at.

  • spider_0072spider_0072 Member Posts: 4
    I had the codes read and a P0420 code came back. I read that it was probably the 02 sensor or the cat that was bad. Since I just changed the cat I decided to change out both 02 sensors. I disconnected the battery for 15 minutes and then reconnected it. The light stayed off for about 20 miles and came back on with the same code. Do I have to have the code cleared with the odb reader or should disconnecting the battery do the same thing? I can't pass the emissions test with the light on and I'm not sure what direction to go from here. Any ideas?
  • ken02ken02 Member Posts: 1
    my girl bought this Pontiac, used about three years ago. The gas gauge is faulty. It will read full until you have about 1gal left in the tank, then boom!, empty. Gas pedal sticks every once in a while. Just came across a new problem, then engine seems to gasp for air, chocking, loss of power, while I'm accelerating. Starts to ping when it top out." No engine light " trying to diagnose put in a new fuel filter. Bleed the fuel lines, check the sensors, etc... nothing still the same. Take it to a local shop to run a diagnostic cant find it. No engine light . he does a book inspection everything is holding its own due to no light he cant put a nail in it. On my way home engine light comes on, take it back he runs one, comes back as random misfire,cant pin point it so I'm back to square one! Take it to another shop , the guy jumps in it, turns it on, reves the engine jumps out and says it my cat converter. Need to know what is manuf. warranty on cat converter in a 02 Grand Prix? thanks Ken02 9-18-08
  • c29160c29160 Member Posts: 5
    I have no suggestion for your fuel gage other than the sending unit is bad. and you might check the tank itself, a dented tank can hold the float up and read full. make sure it has the right fuel cap, a non vented system with a non vented cap can cause the tank to collapse. for your missing check the coils and the coil pack, also when was the last time it had new plugs and wires? my 2002 was showing random misfire and when I replaced the plugs and wires it went away. if your ecm works as it should a bad cat will show a code P0420. also check the fuel pressure on the fuel rail a bad fuel pressure regulator can cause the same symptoms. fuel pressure should be 52-59 psi with the pump running and the engine off. there ist enough time to go over all the possibilities here but those are the basic starting points, hope it helps
  • latashaclatashac Member Posts: 1
    I own a 2000 Grand Prix GT V-6 it has about 117,000 miles on it and really since I have had it I have not had any major problems with except for the normal maintance. Since I have pd it off this year I have begun to have a problems.. First it would turn over,but it would not stay start so I replaced the Air flow take sensor and also had a induction flow before I put the sensor on and that did not work. Once the sensor was put on it started and stayed started,but it ran a little rough so back to the shop we go (I work for White Tire ) the same day I took it back to them the CHECK ENGINE LIGHT comes and stays on so the hook it up to the computer and it tells them something from the 02 sensor, and right now the light is still on. I do not know what to do?????

    Anyone have a suggestion or a similar situation please help :(:(:(
  • sjennings1sjennings1 Member Posts: 1
    Im am in the process of purchasing a 2001 grnd prix GT w/ 67000 miles. I am currently the proud owner of a 2003 freelander land rover and has nothing but problems. I still owe 9000 on it and can't afford a new car right now. Just curious.
  • spider_0072spider_0072 Member Posts: 4
    It depends on the code but it could be that the catalytic converter is bad, this will cause performance issues. If you do have to replace it I would make sure that you put in new O2 sensors too. You could try to replace the O2 sensors first, about $80 a piece, to see if that fixes it. There is one in the exhaust manifold and one directly after the catalytic converter. Don't buy an aftermarket cat, make sure you buy an OEM converter. They cost a little more but I have heard of problems coming from aftermarket cats.
  • hdfxdwghdfxdwg Member Posts: 6
  • hdfxdwghdfxdwg Member Posts: 6
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