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 Pete Your Own Question
Pete, Pontiac Technician
Category: Pontiac
Satisfied Customers: 28794
Experience:  17 Years Pontiac Technician and training.
Type Your Pontiac Question Here...
Pete is online now
A new question is answered every 9 seconds

Pontiac Grand Prix GT I have a 2001 Pontiac Grand Prix with

Customer Question

I have a 2001 Pontiac Grand Prix with some codes. I first got the code, P0332 - Knock Sensor 2 Circuit Low Input (bank 2).
Recently my car has started to run bad, misfiring. Now it has these codes.
P0201 - Injector circuit open cylinder 1, P0301 Cylinder 1 misfire detected, P0332 Knock Sensor 2 Circuit Low Input (bank 2), P0420 Catalyst Efficiency Below Threshold (bank 1), P0201, P0301, P0332, P0420.
What do I need to fix?
Submitted: 6 years ago.
Category: Pontiac
Expert:  Pete replied 6 years ago.
Hello,I will be glad to try and assist you with this,Welcome to Just Answer.


Code P0332 will set most likely on this model if the knock sensor has failed.If the engine actually has a knock in it then this can cause this problem as well.But this code may have set due to the misfire in the engine.I would correct the misfire first to see if this code doesn't set again.

Codes P0301 and P0201 are related.The injector circuit is open so it isn't firing off injector 1 which is causing the misfire as well as the bad running.Check the wiring harness to the injectors and make sure no wires are broken,chewed through by rodents or cut and grounded.If any problems are found here then the wiring needs repaired and should correct this.If you have no wiring issues then you may have a faulty fuel injector,the injector would have to be tested by a shop or dealer to see if it is the injector itself at fault.

The code P0420 sets when the catalytic converter is failing.This usually ends up with having to replace the catalytic converter to correct this fault.

The only other thing that can cause the P0420 to set is if you have leaks in the exhaust system or after market exhaust components,or bent damaged exhaust components.If all of these are o.k. then you need a new catalytic converter.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Customer: replied 6 years ago.

I replaced my catalytic converter 4-5 years ago.

Could it be something as simple as a bad plug?

also, about how much would a new fuel injector run me?

Expert:  Pete replied 6 years ago.
It may be possible that the misfire is causing the catalytic converter code but usually with the catalytic converter code setting this indicates a faulty catalytic converter.Most converters have a warranty and you might want to see if yours is covered under warranty if it is faulty.

I don't think you have a plug at fault here due to the injector circuit code.The injector circuit code is causing the misfire.The circuit would need tested and if the injector is found faulty it would need replaced.

Most of the injectors usually run around $100 for the part and about an hours labor to have replaced.

You can correct the injector/misfire fault first then clear out all codes and drive the vehicle to see if any codes come back,if none come back then you should be good to go from there.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!