do you need to recalibrate ECU after replace catalytic converter? - Camry Forums - Toyota Camry Forum

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Old 12-21-2009, 09:56 AM
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Default do you need to recalibrate ECU after replace catalytic converter?

i recently purchased for my wife a used 2003 4-cyl Camry, a/t, 125000 miles, from a toyota dealer. Nice car. After a couple weeks, the check-engine light came on. I got out my Actron OBD II code scanner, which i used to retrieve a P0420 DTC. I researched that DTC on the internet and found out it is a "catalytic converter not performing to spec" issue. I erased the code, and it has not returned in the month since then. I dropped by the toyota dealer to discuss the issue w/ a service tech, who told me that altho i could replace the catalytic converter myself, i would still need to bring it by to them so that they can "recalibrate the computer" after the new catalytic converter has been installed. Back in the 60s and 70s, i had A LOT of experience working on VW Bugs, rebuilding Bug engines, even once rebuilt a VW bug standard transmission. So i like to think i know a little bit about auto mechanics. But back then, VW Bugs did not have catalytic converters, much less onboard computers. So i need to know: on MODERN cars, do you need to recalibrate the onboard computer whenever you replace the catalytic converter? I have both the Chilton AND the Haynes shop manuals for this car, and neither one of them mentions any such requirement. One further note: I found a TSB for this car on the internet, Toyota TSB EG024-04, relative the onboard computer and P0420 DTCs, but the tech at the dealar told me it does not apply to *my* engine b/c it was built after the Production Change Effective VIN (and that jives w/ what i concluded).
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Old 12-21-2009, 10:41 AM
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if u changed the compression u may need to... or if u put in a new o2 reader... which u should have at the cat converter replacement. i know i had to cancel it out on my honda... but we couldnt get it to read the o2 reader right.

if you can get it to read the o2 reader right. and compression hasnt changed then ur fine. if compression changed ur cars guna drive driffrent
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Old 12-21-2009, 12:02 PM
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Suggest you ask the Toyota dealer exactly what is meant by recalibrate. This may be an engine computer software memory reflash (a computer software update).

Manufacturers sometimes update the software of a specific years/model of cars computer to fix problems such as drivability and trans shifting. Any updates should be listed in a TSB listing the effected years and models of car. Maybe there is one for your car but related to another issue, not the converter.

Have never heard of a dealer reflashing the computer due to a converter change.
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Old 12-30-2009, 06:25 PM
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Default do you need to recalibrate ECU after replace catalytic converter

Thanks for the replyIs there any hp gain from ecu tuning, or is it more improved drivability? upping the redline would be nice.Which ECU would I need? P75 or P74?
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Old 12-30-2009, 10:15 PM
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Sorry not up to speed on P74/75.

The Autopartswarehouse lists replacement ECU's and chips that can be programmed.

Would assume the engine was built for a mix of fuel economy and some performance. Thus doubt if there would be any significant gains in reprogramming the computer.

Is this car built for the non-USA market?
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