Help po420 po430 codes
Thread Starter
Pro
Joined: Apr 2005
Posts: 715
Likes: 4
Help po420 po430 codes
Hi I have a 1999 6 speed coupe all stock except a cold air intake.I have had the car since feb last year and keep getting the codes(po420/po430).I have read that its o 2 sensors or cats.How would you go about fixing it?What would you replace first?Cats or 0 2 sensors?I cant stand the fumes any more!!!!PS but the car still runs good but stincks!Thanks for any help.Dan
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
Those codes belongs to rear cats, it just annoying DIC light otherwise those codes dont effect performance, heck u can disable them whenever u want, but the tuner can disable those codes permanently. Usually they activate when u have aftermarket exhaust like LT headers.
If i were u check the rear 2 cats if they r really not working or how thier condition are.
BTW just type "240 and 430 " in search function this topic discussed to death.
If i were u check the rear 2 cats if they r really not working or how thier condition are.
BTW just type "240 and 430 " in search function this topic discussed to death.
Le Mans Master
Joined: Nov 2005
Posts: 6,993
Likes: 25
You hook up a graphing code scanner and wath the voltage for all the O2 sensors is the correct way to diagnose this. If the car has a lot of miles the O2 are most likely due for replacement. I think the rear O2's are the heated ones. If the Cataylst goes, the MIL will set with a "Catalyst Efficiency" warning (assuming the O2 are working correctly). If your under the car, bang on the catalyst and listen for "Chunks", when the catalyst dies, is usually disentegrates (That's 1 bad reason for rear mounted turbos).
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