1997 Grand Marquis Check Engine Light

[dubble6s]

Hello Everyone,

I had the "Check"Engine" light come on for the first time since owning the vehicle (actually now its my mother-in-law's). I went to AAP and they plugged it in for me. Here is what the output was:

Advanced Auto Parts

Vehicle Scanned
Global OBD II
Vehicle

DTC (Codes)

P0430
Catalyst Efficiency
Below Threshold (Bank 2)

DTC Pending (Codes)

P0430
Catalyst Efficiency
Below Threshold (Bank 2)

I discussed this with the folks in the store and their conclusion was the O2 Sensor is reading a low output from the catalytic converter, meaning the catalytic converter needs to be replaced.

So I ask all of you as you have all been so very helpful to me in the past if you have seen this before and/or agree with this diagnosis. Is it possible that just the 02 Sensor is bad?

Thank you very much,
Rich
Dubble6s

[reekor]

Exhaust leaks will genearte that code, so will dirty MAF sensors.

If the rear 02 sensor is following the front 02 sensor in terms of voltages, cross counts, waveforms, I would replace the converter. Your car has two converters, you can always swap the left and right 02 sensors and if your code comes back as a P0430 then you know that you have a converter issue or if the car starts triggering a P0420 code you'll know that it's a 02 sensor issue.

Originally Posted by dubble6s

Hello Everyone,

I had the "Check"Engine" light come on for the first time since owning the vehicle (actually now its my mother-in-law's). I went to AAP and they plugged it in for me. Here is what the output was:

Advanced Auto Parts

Vehicle Scanned
Global OBD II
Vehicle

DTC (Codes)

P0430
Catalyst Efficiency
Below Threshold (Bank 2)

DTC Pending (Codes)

P0430
Catalyst Efficiency
Below Threshold (Bank 2)

I discussed this with the folks in the store and their conclusion was the O2 Sensor is reading a low output from the catalytic converter, meaning the catalytic converter needs to be replaced.

So I ask all of you as you have all been so very helpful to me in the past if you have seen this before and/or agree with this diagnosis. Is it possible that just the 02 Sensor is bad?

Thank you very much,
Rich
Dubble6s