2005 prix engine code question

[meltboy1]

I have a friend with an. 05 prix with codes p0420 and p0455, what would throw those codes?

[slick]

First one is catalyst efficiency.

 

Second one is EVAP leak.

 

You could try to measure the voltage of the rear O2, make sure it's in good range. I've heard that you could also take a temperature reading before and after the catalytic converter. If the drop is large enough, you could have a plug.

 

Evap stuff is always a pain in the ass to diagnose. Try a new gas cap first, and go from there.

[BXX]

P0455, replace your EVAP vent solenoid. They are like $30 from the dealer. Might as well get a new gas cap while you are there as well (save you the hassle later on)

 

Very common to fail, so common in fact that any dealer will stock the item or they might be sold out

 

Fix that, erase the codes. See if the P0420 comes back on. After the reset, dont hammer on the vehicle, drive it like a normal person. Ive seen some S3 3800's throw these codes after little johnny borrowed dear old dads new car and ran the piss outta it. If you hit COT (cat over temp) a time or 2 the convertor is too damn hot to work right and tends to throw the efficiency code.

 

Orrrrrr, the convertor could just be bad.

[slick]

Huh.... good to know...

[AL]

Thats good to know Bob... On that subject, My buddy just got the CAT replaced on his Bonne and still gets the code... I watched the rear 02 sensor data and sometimes its fine and sometimes its way out of wack, would an 02 sensor going out be intermittent like that

[IRONDOG442]

Not you again, I thought we had an agreement!

[BXX]

Thats good to know Bob... On that subject, My buddy just got the CAT replaced on his Bonne and still gets the code... I watched the rear 02 sensor data and sometimes its fine and sometimes its way out of wack, would an 02 sensor going out be intermittent like that

 

Could be.. Or it could be a junk replacement convertor. Most of the cheap chinese (or the like) replacements dont work worth a fuck. Get a Catco or OE or go home!!!

 

And everytime ive replaced a convertor on a car, you better believe it got a new downstream O2!! Might as well while you are there!

[terryk2003]

Is the exhaust stock? I know when people replace their downpipes with the aftermarket ones with the "high flow converters" they tend to throw that p0420 code as well...

[BXX]

Yeah, high flow = low efficiency

[1990lumina]

Throw some spark non foulers on the rear O2 sensor is it has a high flow cat..or no cat.. That'll make the P0420 code go away for about $10

[BXX]

Throw some spark non foulers on the rear O2 sensor is it has a high flow cat..or no cat.. That'll make the P0420 code go away for about $10

 

Yeah, I heard that works pretty good! Never tried it though since the only vehicle I replaced with a higher flowing cat and not a OE or Catco OE was my cutlass, and I deleted the downstream O2 and the code in the PCM as well

 

No check engine FTW!

[terryk2003]

Throw some spark non foulers on the rear O2 sensor is it has a high flow cat..or no cat.. That'll make the P0420 code go away for about $10

 

Yeah, I heard that works pretty good! Never tried it though since the only vehicle I replaced with a higher flowing cat and not a OE or Catco OE was my cutlass, and I deleted the downstream O2 and the code in the PCM as well

 

No check engine FTW!

 

i also read about the defaulers, but if mine throws that code again i'm just gonna have the code deleted as well...it used to throw it every time i drove for a while but i havent seen it since i put the new exhaust on...