08 Denali... P0420 Error Code.

[wsuwrhr]

Maybe some things shouldn't be talked about on public boards? Just thinkin out loud.

 

[Bigbore500r]

Maybe some things shouldn't be talked about on public boards? Just thinkin out loud.

We are talking off road use only vehicles, participating in sanctioned racing events. Like the OP's Denali, that's what its for right?

 

[wsuwrhr]

Yessir....Im just thinkin the peeps that don't know how those things work, prolly don't need to know.

We are talking off road use only vehicles, participating in sanctioned racing events. Like the OP's Denali, that's what its for right?

 

[rush1]

Except HP Tuners, EFI Live...etc - I can make those monitors say whatever we want. 02 monitors ready? Sure!

True ,but what did you pay for your tunner? I forgot about them ,I don't think your regular Joe should be playing with a tunner much

 

[LargeOrangeFont]

True ,but what did you pay for your tunner? I forgot about them ,I don't think your regular Joe should be playing with a tunner much

If you know someone with the software, at most $100 for 2 credits to unlock your VIN.

 

[mc1081]

Looked up the error code and it says that my #1 cat has issues. Went to Dr. Google and said to replace O2 sensor. However, most say the CAT is shot. With that being said:

Replace the #1 cat only OR replace both with aftermarket cat system. My boat mentality is to throw on headers and a cat back muffler system also. Any recommendations for a complete system or put-together system?

Looked up the error code and it says that my #1 cat has issues. Went to Dr. Google and said to replace O2 sensor. However, most say the CAT is shot. With that being said:

Replace the #1 cat only OR replace both with aftermarket cat system. My boat mentality is to throw on headers and a cat back muffler system also. Any recommendations for a complete system or put-together system?

I had the same problem a month ago on my 2007 Denail. This is what I did.

**Recommended by smog service technician:
1) I poured Lucas Octane booster (1 bottle)
2) I ran vehicle at 4,000 RPM for 10 Min. and it must be continuous.
3) Then run the vehicle normal for 10 min.
**The above steps is supposed to clean the Catylist converter.

As a precautionary step:
**I replaced the bank 1 and 2 oxygen sensors (aprox. $70 each), and passed SMOG flying colors including saving big $$$ by not replacing cat converter.

 

[LargeOrangeFont]

I had the same problem a month ago on my 2007 Denail. This is what I did.

**Recommended by smog service technician:
1) I poured Lucas Octane booster (1 bottle)
2) I ran vehicle at 4,000 RPM for 10 Min. and it must be continuous.
3) Then run the vehicle normal for 10 min.
**The above steps is supposed to clean the Catylist converter.

As a precautionary step:
**I replaced the bank 1 and 2 oxygen sensors (aprox. $70 each), and passed SMOG flying colors including saving big $$$ by not replacing cat converter.

That just burns up any deposits that might be in the cat. Generally speaking the cat should not be going bad after 10-11 years unless there was some other problem.