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peterpete190, Auto Technician
Category: Nissan
Satisfied Customers: 29067
Experience:  Over 17 years diagnosing and repairing vehicles.
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I have my daughters 2001 Nissan Pathfinder with less than

Customer Question

Tim, I have my daughters 2001 Nissan Pathfinder with less than 135k miles. I replaced two O2 sensors in the car. It does not consistently throw a code, but occasionally shows P0420 and PO430. there is a TSB indicating that this is programming on the ECM and we should not replace the catalytic converters. I have had Nissan check it without any codes and today it throws the code. But then it clears it?
Submitted: 1 year ago.
Category: Nissan
Expert:  peterpete190 replied 1 year ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Was the programming done that needed to be done by a dealer and the codes are still setting?

Let me know so we can continue,thanks Pete.

Customer: replied 1 year ago.
Originally I was getting MIL ON, PO138 & 139 and many other codes. I replaced the two lower O2 sensors for PO138 & PO139. Reset the car with the code reader. I only get the MIL ON, PO420 & P0430 occasionally. Unfortunately, I took it to the dealtership to see if they would execute the NTB02-87a Nissan Service Bulletin on the car without them seeing the codes, I reset it before I took it too them almost 3 weeks ago. They will not do it at the Autonation dealership. I received the codes last night and this morning. But it cleared before I can get it to the dealership? I don't think changing the catalytic converters will be the only fix, but if they don't do this work? I can pass emissions.
Expert:  peterpete190 replied 1 year ago.

Have you actually checked with a scan tool to see if these codes cleared out or to see if they are stored in the computers memory as a history code?

Customer: replied 1 year ago.
Pete, I have two scan tools. but they don't have any memory. I can check it again during lunch.
Expert:  peterpete190 replied 1 year ago.

O.k.,I think the only way you will get them to program the computer is if they see the code in current or history.If you did not clear them out with your scan tool when the codes set last and this was just recent that they had set the dealer should be able to see the codes still to do the reprogramming now.The only other cause is the catalytic converter itself (or both if you have 2 since you have 2 codes for them) would need replaced.They can intermittently set the code and is very common when they just start to fail/act up.I would see if you can get this reprogramming done to see if this corrects the fault first.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
I checked the car and it still had PO430. I cleared the code. but the MIL was off and the PO420 was off from last night.
Expert:  peterpete190 replied 1 year ago.

Is the code P0430 set now?

Customer: replied 1 year ago.
No. All codes are gone. I checked twice.
Expert:  peterpete190 replied 1 year ago.

O.k.,unfortunately the only way the dealer can reprogram the computer is if they see these codes.You might be able to contact Nissan customer service to see if they can push the dealer to reprogram it here.Then once this is done if the fault does come back then I suspect you may have a fault with the catalytic converter system needing replaced.

Let me know if you need anything else and feel free to rate my help here.

Thanks Pete