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I just bought a car for a really low price with these engine codes. The guy told me that someone told him 02 sensor. Also I noticed that this outlet near the engine didn't have a connector in it. Maybe this is related to these codes? Any help is appreciated. Thanks!

The codes are
P0172
P0498
P0453
P0420
P0498 again?
P0172 again?

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^^vv<><>BA
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P0172 ... could be MAF sensor


P0498


P0453... FTP (File Transfer Protocol Fuel Tank Pressure) sensor?


P0420... could be bad catalytic converter or O2 sensor... or PCV valve

I got the P0420 a few years back. I replaced the PCV valve and dumped a bottle of Red Line Complete SI-1 Fuel System Cleaner in the gas tank. Fixed the problem.
 

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Discussion Starter #3
P0172 ... could be MAF sensor


P0498


P0453... FTP (File Transfer Protocol Fuel Tank Pressure) sensor?


P0420... could be bad catalytic converter or O2 sensor... or PCV valve

I got the P0420 a few years back. I replaced the PCV valve and dumped a bottle of Red Line Complete SI-1 Fuel System Cleaner in the gas tank. Fixed the problem.
Thanks man! I cleaned the MAF sensor yesterday and doesn't seem to be fixed but that doesn't mean its not faulty... I ordered a front catalytic convertor so hopefully that will help but I might put a PCV valve on it based on your post.
 

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I believe the P0420 is the result of what's being reported by the downstream. Plus it's cheaper to do. Do that one first and see if it helps. If not do the front. How many miles on your car?
 

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I believe the P0420 is the result of what's being reported by the downstream.
That's true. The cause for the low efficiency below the threshold is either due to the cat or the downstream O2 sensor (sensor #2).

I got the codes for efficiency below the threshold when my car was around 500k. I replaced the cats for banks 1 and 2. Codes remained cleared after that til recently. I just replaced both of my downstream O2 sensors the other day around 676k. No codes now.
 

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Before I put a new Catalytic converter on it you need to solve the P0172 error, those evap errors are an issue but they will not destroy a catalytic converter but a P0172 will. Some how too much fuel is getting in the combustion chamber as measured by the O2 sensor.

You need to look at the fuel trims and see how bad they are. They should be 0 to +/- 8 percent. The code P0172 is set when files trims are +20%.

It could be a bad MAF or coolant sensor, but something is adding more fuel, possibly even a bad primary O2 sensor. It could also be a bad catalytic converter, I assume the engine is running badly? Take a look at each sparkplug and see if 1 is fouled with carbon. Doing a compression test is not a bad idea as well.


Post the freeze frame data from the P0172 and the short term and long term fuel trims. Double check the coolant and intake temperatures are reporting correctly.


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It's been my experience that O2 sensors are good for 120-150K. I've replaced them on 5-6 cars and that's been the mileage range. I just replace both and usually am able to forget about it.
 

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It's been my experience that O2 sensors are good for 120-150K. I've replaced them on 5-6 cars and that's been the mileage range. I just replace both and usually am able to forget about it.
I'll do both then to save the effort in seeing which one needs it
 

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They're both pretty easy. The downstream plugs into the car underneath the PS front seat. Just shove the seat all the way forward and you can get at it from behind the seat. Its also very easy to remove the seat's four mounting bolts and lift out the seat.
 

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Yes your fuel trims are wacked, the short term and long term are additive, so right now the ECM has removed 40+ % of the fuel. That is what set the code. Your ECT looks good, so does your intake air temp. The 13 in hg at idle is low, that should be considerably higher. The question is how is more fuel getting in the combustion chamber.

Possibly the evap is sucking in fumes from the gas tank due to the valve failure. Maybe you should concentrate on fixing the evap system and see if the fuel trims come down. Otherwise you are looking at a possible leaking fuel injector.

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Does anyone know what that sensor is in the intake tube and why it does not have a connector plugged in?

You would think there would be an error for that?

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Discussion Starter #14
That's true. The cause for the low efficiency below the threshold is either due to the cat or the downstream O2 sensor (sensor #2).

I got the codes for efficiency below the threshold when my car was around 500k. I replaced the cats for banks 1 and 2. Codes remained cleared after that til recently. I just replaced both of my downstream O2 sensors the other day around 676k. No codes now.
Miles or km?
 

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Yes your fuel trims are wacked, the short term and long term are additive, so right now the ECM has removed 40+ % of the fuel. That is what set the code. Your ECT looks good, so does your intake air temp. The 13 in hg at idle is low, that should be considerably higher. The question is how is more fuel getting in the combustion chamber.

Possibly the evap is sucking in fumes from the gas tank due to the valve failure. Maybe you should concentrate on fixing the evap system and see if the fuel trims come down. Otherwise you are looking at a possible leaking fuel injector.

Sent from my Pixel 2 using Tapatalk

Does anyone know what that sensor is in the intake tube and why it does not have a connector plugged in?

You would think there would be an error for that?
Oh hell so here's someone you need to start listening to. LOL. I've only ever had to deal with the P0420.
 
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Also I noticed that this outlet near the engine didn't have a connector in it. Maybe this is related to these codes?
You would think there would be an error for that?
That's an intake air temperature sensor. Only 03-04 non-SULEV have that. From what I can tell OP, has an 06-07 SULEV. Someone must've swapped the intake pipe at some point. OP's car doesn't need it, so it being disconnected has nothing to do with the codes.

522704
 

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I did not think so, as there was no code for a missing IAT, and there is a reading. It may be a dummy plug as it is listed in the parts diagrams of all engines just no description in those that do not use it.

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