2005 Nissan Pathfinder service engine light plus gas smell

service engine soon light just came on. earlier today i noticed i smelt like a gas smell and when i started it this morning i noticed that it seems to idle high. what could this be?

Thanks for the question. If the service engine soon light is on - the little yellow engine symbol, right? The light is telling you some thing is wrong that need to be repaired. There are diagnostic codes stored that can be read to help direct the mechanic to the problem. Without listing those codes here, the list of potential problems is quite large. Local auto parts stores can read those codes for free. Have that done and post back the codes - the format should be P0xxx where xxx is the number code for the problem.

If you aren’t going to fix the car yourself, take it into a mechanic. If that light starts flashing, stop driving the car immediately and have it towed to a mechanic!

The easiest way to find out is to have the codes read. The check engine light is just there to tell you that the computer is getting bad readings from a system censor. The codes tell you what system. It is up to you or your mechanic to diagnose what is causing the bad sensor reading.

thank you. Autozone said error codes P0430 P0430 catalyst system effeciency
below threshold (bank 2)

this car is old, likely is well above 100K miles on odometer. I have the one from 2006.

the code tells "catalytic converter is bad in Bank#2:

do not rush replacing the catalyst, it very well may be just fine and the reason for the code may be in downstream oxygen sensor getting old. this is old car.

replace the downstream sensor in bank 2, clear code, drive on. if the same code returns, at that point you might consider replacing an upstream catalytic converter, it will look like this one: https://www.amazon.com/gp/product/B00C6Y7G5A/ref=ox_sc_sfl_title_23?ie=UTF8&psc=1&smid=A2F8QH83YSA2LG

the downstream converter is not getting monitored and will not be able to raise any “check-engine” codes, but once you touch the flanges in your old truck, likely you will have a flange broken off it (I had that issue), and you would need to replace both in the end

so, go with cheap sensor replacement before you touch any “big stuff”

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Agree with sensor replacement. Maybe, just maybe that is contributing to the gas-smell. That might be a stretch for just the sensor.

As @thegreendrag0n suggests, a broken flange can cause the code, too, but also cause the smell. I’d be looking carefully at the exhaust for cracks and flange failure.

my journey involved code related to the flange leak too, it was not P0420/P0430 one, but rather P2A00, so ECM was sensing oxygen coming from the leak on the broken flange, it raised a different kind of alert for this

originally, my P0420 (twin-brother of P0430) was accompanied with gas smell from exhaust too, but I was too quick jumping the gun and replacing an upstream cat, which I regret in back-vision, if I tried replacing downstream sensor first, maybe I would not have the rest of “entertainment”

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Thank u much😀

@brown14, that would be nice if you post your resolution here.
we all like to know if you resolved the issue and how.

Thank u. Was O2 sensor.u guys rock!!awesome

How many miles you drove after repair?
If you exceeded 200, I would say, you are out of this wood :slight_smile:
Thanks for posting back!

Here’s some very important questions?

After the repair, did you erase the codes?

did you verify that the catalytic converter readiness monitors ran to completion, AFTER you erased the codes?

If the answer to the last question is no, my statement is “You do not yet know if the issue is resolved”