PCM P0420 error on 2005 deville 4.6 49k miles

1240 Views 3 Replies 4 Participants Last post by 98eldo32v, Mar 4, 2015

mluplow

Discussion Starter · Mar 3, 2015

I just had the MAP sensor replaced and a coolant leak fixed at a shop. a day later i got the SES light and P0420 (catalytic converter) code. I reset it and it came back on a couple of days later. My question is: should a catalytic converter fail after only 49K miles? Also, is there anything the the shop could have unplugged or pinched an 02 sensor wire or anything else while doing their service? Strange that this is the first time this error came up. Tomorrow I will get the car warmed up and get the temp of the front of the cat and rear of the cat and see if it is bad. That's how we used to check them. Hotter in rear of the cat normal, hotter in the front clogged. BTW, no loss of power. Thanks for everyone's help.

Mark

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basscatt

· #2 · Mar 4, 2015

mluplow said:
I just had the MAP sensor replaced and a coolant leak fixed at a shop. a day later i got the SES light and P0420 (catalytic converter) code. I reset it and it came back on a couple of days later. My question is: should a catalytic converter fail after only 49K miles? Also, is there anything the the shop could have unplugged or pinched an 02 sensor wire or anything else while doing their service? Strange that this is the first time this error came up. Tomorrow I will get the car warmed up and get the temp of the front of the cat and rear of the cat and see if it is bad. That's how we used to check them. Hotter in rear of the cat normal, hotter in the front clogged. BTW, no loss of power. Thanks for everyone's help.

Mark

==========================
My question is: should a catalytic converter fail after only 49K miles?
no - of course not -
typically - they go hundreds-of-thousands of miles without problems -
UNLESS you have a fuel-related problem -
dumping raw/additional fuel into the exhaust -

is there anything the the shop could have unplugged
or pinched an 02 sensor wire
or anything else while doing their service?
no - all that stuff is monitored -
and would have set a code - and illuminated the CE light -

==========================

I recommend the EASTERN CATALYTIC 50410 -
direct-fit for your car -
best deal I found was $165 - including shipping -
through ROCKAUTO.COM -

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drewsdeville

· #3 · Mar 4, 2015 (Edited)

A 2005 with 49k - I wouldn't bother bolting a cheaper, half aluminized unit onto presumably clean stainless pipes - you can bet on replacing it again down the road, depending on your location. Get yourself a nice all-stainless unit and forget about it.

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98eldo32v

· #4 · Mar 4, 2015

Catalytic converters don't like excessive amounts of raw gas or coolant in them.

Check oxygen sensor again for efficiency with a scan tool that can log real time switching if possible, other than that, USUALLY a 420 is dead on.

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