How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask RussMasterTech Your Own Question

RussMasterTech
RussMasterTech, ASE Certified Technician
Category: Car
Satisfied Customers: 791
Experience:  19 years of GM Dealership experience. ASE Master with L1 and GM Master Certified.
Type Your Car Question Here...
RussMasterTech is online now
A new question is answered every 9 seconds

2001 pontiac Grand Prix 3.1 V6 - i get the diagnostic

Resolved Question:

2001 pontiac Grand Prix 3.1 V6 - i get the diagnostic code P0420 - the catalytic converter was replaced 6 months ago and my check engine light is still on. Any suggestions what my next step should be?
Submitted: 6 years ago.
Category: Car
Expert:  RussMasterTech replied 6 years ago.

Hey there Customer.

If you had an aftermarket converter installed, then the converter could still be the problem. I have had nothing but bad luck with aftermarket converters and the code p0420. I just had one at our shop where the customer was coming in to get there converter replaced under the GM special policy for the converters plugging up, but they already had replaced it with an aftermarket converter and it was causing th p0420 to set. They couldn't get the GM converter because they had already replaced it.

The trouble code chart is pretty simple on that code. It basically says, if the p0420 is set, then replace the converter. One thing that will cause premature failure of a new converter is a misfiring engine. Before you have the converter replaced again, make sure the engine is running well. Have the ignition components inspected, if the plugs are original, perform a tuneup and maybe even have the injectors cleaned.

Thanks for using Just Answer.

Russ

RussMasterTech, ASE Certified Technician
Category: Car
Satisfied Customers: 791
Experience: 19 years of GM Dealership experience. ASE Master with L1 and GM Master Certified.
RussMasterTech and 3 other Car Specialists are ready to help you
Customer: replied 6 years ago.
Hello, thank you for your quick response. I need a little more clarification. The catalytic converter was replaced because the vehicle was running horribly. There was a significant loss of power. Also, when driven, the car would not shift gears and it would run at high RPM's. The first step I took was to tune up the vehicle. I replaced the plugs, wires as well as the air filter. I also cleaned the fuel injectors and throttle body. After all that I realized there was no difference in the cars performance. So I replaced the catalytic coverter. That solved the performance problem however the check engine light continued to stay on. I used a hand held code reader to clear the diagnostic code. I ran it for a whole day but the check engine light never came on. But when I hooked up the code reader again to see if all the systems had run their checks the same code appeared. After I unplugged the code reader and restarted the car the check engine light DID turn back on. Any additional information would be greatly appreciated.

Thank you,
Jesse
Expert:  RussMasterTech replied 6 years ago.

If the new converter was functioning correctly, the code should have run and passed and the light should have gone out by now. I really think if you put an aftermarket converter on the car, that it may not be efficient enough to pass the OBD2 GM threshholds. One thing you may want to consider is getting reimbursed from GM for the cost of your converter. Like I stated earlier, they have a special policy on the converters, and they would have replaced it at no cost to you if you would have taken it to a dealer. You should can a Pontiac dealer and see if you can get reimbursed.

I know this is frustrating, but sometimes aftermarket parts just aren't the answer.

 

Thanks for using Just Answer.

Russ

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
< Last | Next >
  • I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry. Stephanie P Elm City, NC
  • used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future. David L. Richmond, TX
  • 9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much. Phil Marysville, CA
  • Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible. Charles Walnut Creek, CA
  • As a single woman, I really appreciate an excellent and affordable opinion.
    Thank you Geordie, I will not hesitate to contact justanswer in the future!
    Sue Charleston, WV
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff. Jim Castleberry, FL
  • Excellent reply, and also very quick. Really sounds like the Expert knows what he is talking about. I will be back to use your service when I need more help with my RV. Dutch USA
 
 
 

Meet The Experts:

 
 
 
  • Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
< Last | Next >
  • http://ww2.justanswer.com/uploads/MU/muddyford/2012-6-13_1204_1.64x64.png Chris (aka-Moose)'s Avatar

    Chris (aka-Moose)

    Technician

    Satisfied Customers:

    846
    16 years of experience
  • http://ww2.justanswer.com/uploads/TE/TedG/2012-6-15_14759_avaLarge.64x64.jpg Ted G.'s Avatar

    Ted G.

    ASE Certified Technician

    Satisfied Customers:

    1596
    20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness
  • http://ww2.justanswer.com/uploads/joecamel90/2008-11-13_03615_head_shot.jpg George H.'s Avatar

    George H.

    ASE Certified Technician

    Satisfied Customers:

    1311
    ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist
  • http://ww2.justanswer.com/uploads/AM/amedee/2013-10-24_23656_Amedee1.64x64.jpg Amedee's Avatar

    Amedee

    ASE Master Tech

    Satisfied Customers:

    2367
    ASE Master Tech advanced level specialist
  • http://ww2.justanswer.com/uploads/SU/supermechanic/2013-8-23_03546_500.64x64.jpg Jerry's Avatar

    Jerry

    Master Mechanic

    Satisfied Customers:

    1906
    ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager
  • http://ww2.justanswer.com/uploads/CR/crzydrvr00/2013-11-3_12123_246347.64x64.jpg Richard's Avatar

    Richard

    ASE Certified Technician

    Satisfied Customers:

    942
    12 years Ford Lincoln/Mercury Jaguar dealership as a technician and shop foreman reparing all makes
  • http://ww2.justanswer.com/uploads/ST/Steve7654/2012-6-5_215929_japic800x660.64x64.jpg Steve's Avatar

    Steve

    Auto Service Technician

    Satisfied Customers:

    1980
    25+ yrs experience as a professional working technician; ASE L1 master technician