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Dealer says $3,298.00 plus tx to replace converters, sensors and hardware. Is this a common and or believable diagnosis?
 

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Dealer says $3,298.00 plus tx to replace converters, sensors and hardware. Is this a common and or believable diagnosis?
It is a believable mis-diagnosis.

Was the OBD-II code that started the diagnostic work P0420 or P0430, "Catalytic converter efficiency below threshold"?

The engine ECU monitors all four of the sensors in the exhaust stream, and will post the "catalytic converter efficiency" code if the outputs of either pair of sensors fall outside specific limits. In this case, the ECU assumes that one or more of the cats are bad. However, the validity of the sensor outputs are obviously dependent on sensor condition as well as cat condition, and at over 100K miles your sensors are likely at (or beyond) their useful life if they are the original parts.

I'd replace all four of the sensors (2 fuel-air, 2 oxygen) first, and see if that corrects the problem. Sensor parts cost would be ~$350 through Amazon (using ONLY OEM Denso sensors).

It would be very unusual for both cats to fail simultaneously, unless there was some other severe engine problem that was dumping excessive fuel (or oil) into both cylinder banks.

As an example, I've got 206K miles on my V6 4-Runner, and 240K on a V6 Camry, both still with their original cats.

At some point around 150K miles both vehicles posted OBD-II code P0240 indicating "bad catalytic converters". They both still had their original fuel-air and oxygen sensors. Replacement of the sensors corrected the "bad cats" code, and both vehicles are still running flawlessly, on their original cats, ~60K and 90K miles after the sensors were replaced.
 

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Thank you for your input.
A little more information would be very useful in isolating the problem:

1. What year FJ is this?
2. Was the check engine light on?
3. If so, did the dealer provide the OBD-II codes for you?
4. If not, can you ask the dealer to provide the codes that triggered the "new cats required" diagnosis?
5. Did the dealer reset the check engine light?
6. If so, did the CEL come back on immediately?
7. Do you know if the vehicle still has the original fuel-air and oxygen sensors.
8.Do you know if the mass airflow sensor has ever been cleaned?
 

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Discussion Starter #5
I purchased 2007 auto new from Toyota in Reno Nv. I have never had it serviced anywhere other than a Toyota dealer at prescribed intervals. The issues I'm currently having is that all the dash lights (check engine and under on the right side) will come on and stay on for a few days, the go off for a few days.
The code given was P0430 Catalytic System Efficiency Below Threshold (Bank 2)
RECOMMEND TO REPLACE BOTH MANIFOLD CTS WITH O2 SENSORS.
$2818.04+ TAX PARTS. $480.00 LABOR
This vehicle is not driven hard or excessively
 

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There are a few things I would do before letting the dealer have this kind of money.
Other than the code how is the operation in general.... Have you inspected the exhaust system for noticeable physical damage? What about engine maintenance including spark plugs and the sensors FJT mentioned. I would take the vehicle for a good long somewhat hard highway run and really get some heat in the exhaust and see if the Cat may self clean, this also may show up some other condition that may be an under lying cause of a Cat fail. Before going to the dealer I would seek out a lower milage wrecked FJ in a auto wrecker and take it's Cats, as they are not a common fail part. You can also look to the Aftermarket suppliers for a cheaper option. $500,00 labour is approx five hours work, I would look at the job and see how complex the replacement is and consider doing myself. $3300,00 dollars seems high to me I would be looking at options.... I guess I am frugal.
 

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Good advice posted above!

I may have a set of headers/cats that I won't need and would want to resell. I'm still tracking down the source of an error code and may have jumped the gun when I purchased them from another member here. I have a scan tool en route from Amazon and should know by next weekend if it's just an AF sensor that I need to replace and not the cats. Even if it is the cats, I may go with long tubebheaders anyways.

Tried to PM you, but I think you need to increase your post count before you have access to private messaging here.
 

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Your cats do not require replacement. These cats have a typical service life of 200K+ miles, IF the engine is properly maintained.

What you do need to do is replace the oxygen sensors (actually one air-fuel sensor and one oxygen sensor) on the driver's side (cylinder bank 2). The sensors have a typical service life of 100 - 150K miles. When they start to go bad they frequently trigger the OBD code for low catalytic converter efficiency.

If you haven't cleaned the MAF (mass airflow) sensor in the engine air intake in the last 30K miles, you should, as along with the air-fuel and oxygen sensors it controls the air critical air-fuel ratio, which is whole reason the OBD system is there.

And of course you've been replacing your spark plugs every 30K miles as specified in the Scheduled Maintenance Guide for the '07 FJ?
 

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I had a Cat fail at around 130k. I fixed mine with a set of headers and an O2 simulator from URD. The O2 Sim alone will take care of a cat code (As long as the sensors are good) and it was less than $150.
Underdog Racing Development
 

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I had a cat fail on my 03 impala around 150K miles. You'll notice while driving!!! It was crazy slow and the trans would shift uncontrollably due to lack of power. I also did not throw and code either, just an fyi. As most of the others on here said change the sensors first. Most are very easy to change, as long as little to no rust is involved.
 

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Also if it is the cat itself get a generic one and have a muffler shop cut it in for cheap. Or it maybe time to go high flow :) :cheers:
 

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nope keep the stock cats.. I just fixed mine 👍👍. Cleaned out the cats with Seafoam. Pull the upstream o2 sensors.. spray half a can of Seafoam per side.. Replace o2 sensors let it sit about 30mins.. (word of advice do this outside) after 30 mins start the engine an let it run til the white smoke is gone!!! I sped the process up by driving around my neighborhood in low gear around 2k rpm.. all codes are gone.. fyi my fj has 242k miles on it.. an I wasn't about to spend $2613.38 on new cats!!! $17 of Seafoam for the win!!!!
 
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