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P0420 CODE CATALYST ERROR

wymerm

New member
4
2
3
Buick Ownership
2013 Encore
I have a 2013 Encore Premium that threw this code unexpectedly. The car has almost 100,000 miles on it so I decided to change out the plugs as this can be a cause of this code. I couldn't believe after swapping out the plugs, which certainly needed replaced, the code hasn't returned after nearly 1000 miles of driving. It is a super simple swap. Snap off the engine cover (two snaps in front ..two in back...located about a third of the way in on both sides front and back), lift fairly gently, remove two bolts, lift all four "coil packs" off at one time, remove and replace the plugs put everything back on...done. Takes less than 30 minutes. Use Iridium plugs which is what's recommended. Try this before panicking and throwing a lot of money at this problem. It may be this simple. Whoever engineered this set-up for spark plugs is a genius.
 
Last edited:

DocBrown

Active member
209
45
28
Buick Ownership
2016 Encore Sport Touring
The maintenance schedule for a 2013 Encore says plugs should be replaced at 97k miles.

It's not genius as much as it's the nature of the design of a modern inline engine. Much more difficult with a V6 that's transversely mounted for FWD.
 

wymerm

New member
4
2
3
Buick Ownership
2013 Encore
The maintenance schedule for a 2013 Encore says plugs should be replaced at 97k miles.

It's not genius as much as it's the nature of the design of a modern inline engine. Much more difficult with a V6 that's transversely mounted for FWD.
Genius probably was an overstatement. At least they didn't come up with an insane idea like putting batteries behind wheel wells.
 
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