Trouble Code P0420

**pmolina0436** · 09-09-2008, 04:41 PM

im having this fault on my car, Code P0420, its says the Catalyt Bank one Efficiency below Threshold..????...ummm....im thinking because the LT Headers, but if anyone can give me some info on this issue...Or how to disable the Code??? I do have a Diablo Pred..Thanks for help!!!

**Sarge** · 09-10-2008, 02:47 AM

I would delete the rears altogether.

**0rion** · 09-10-2008, 04:45 AM

do you have hi-flow cats? I would imagine you're right and it's due to the headers. I'd do like the old man says and just delete the rear codes. How old is your diablo? The older diablo's would let you delete those codes but the newer ones won't. Look under the diagnostic menu and see if there's an option to disable those codes.

**pmolina0436** · 09-10-2008, 06:13 AM

Originally Posted by 0rion

do you have hi-flow cats? I would imagine you're right and it's due to the headers. I'd do like the old man says and just delete the rear codes. How old is your diablo? The older diablo's would let you delete those codes but the newer ones won't. Look under the diagnostic menu and see if there's an option to disable those codes.

Well I tried to disable, but i think i have the newer version so it wont give me he option to DISABLE!!It only gave me the option to RESET!!And im actually going to CAT-LEss on my car!!Is there another way to DISABLE???

**0rion** · 09-10-2008, 06:22 AM

not unless you use tuning software or buy O2 sims.

**pmolina0436** · 09-10-2008, 06:24 AM

Originally Posted by 0rion

not unless you use tuning software or buy O2 sims.

Tunning Software????

**FantaZGuy28** · 09-10-2008, 06:46 AM

Originally Posted by pmolina0436

Tunning Software????

HP Tuners

**pmolina0436** · 09-10-2008, 03:29 PM

Originally Posted by FantaZGuy28

HP Tuners

Any other way..I only have Diablo Tunner!!

**pmolina0436** · 09-10-2008, 03:30 PM

Originally Posted by 0rion

not unless you use tuning software or buy O2 sims.

What are 02 Sims???where can i get some??

**Doug_J** · 09-13-2008, 01:40 PM

I have had my Diablo Tunner since march and it lets me erase codes. I thought it was because of me cutting my cats out that it was giving me that code P0420, but my diablo tunner has the o2s turned off.

**0rion** · 09-13-2008, 01:55 PM

Originally Posted by Doug_J

I have had my Diablo Tunner since march and it lets me erase codes. I thought it was because of me cutting my cats out that it was giving me that code P0420, but my diablo tunner has the o2s turned off.

I'm a little confused by what you're saying here. Are you saying your diablo let you turn 420 and 430 off or are you saying you're getting that code after cat removal ( which you will) even though the codes are supposed to be turned off.

**pmolina0436** · 09-13-2008, 04:22 PM

Originally Posted by 0rion

I'm a little confused by what you're saying here. Are you saying your diablo let you turn 420 and 430 off or are you saying you're getting that code after cat removal ( which you will) even though the codes are supposed to be turned off.

by disabling the 02 sensors, will that fix the p0420 code

**0rion** · 09-13-2008, 05:14 PM

Originally Posted by pmolina0436

by disabling the 02 sensors, will that fix the p0420 code

yes, if you just removed the cats disabling those codes will keep the light off. What's not determined is when diable stopped allowing you to do it with their programmer. He says he got his in march but by his statement I can't figure out if he's saying his will turn those codes off or if he tried and is still getting those codes. Also, there are other codes associated with those rear sensors that need turned off if you get rid of the sensors themselves. Heater,activity, and voltage codes.

**pmolina0436** · 09-13-2008, 06:41 PM

Originally Posted by 0rion

yes, if you just removed the cats disabling those codes will keep the light off. What's not determined is when diable stopped allowing you to do it with their programmer. He says he got his in march but by his statement I can't figure out if he's saying his will turn those codes off or if he tried and is still getting those codes. Also, there are other codes associated with those rear sensors that need turned off if you get rid of the sensors themselves. Heater,activity, and voltage codes.

ok checked out my Diablo and when i go to the 02 sensor option (OBD II 02 sensor) it has various codes such as , P0137,P0138,P0141, P0157,P0158 AND P0160, P0161...WHICH SHOULD I DISABLE??? or do i disable them all!!!

**0rion** · 09-13-2008, 06:47 PM

all of them, here's the list for the rear sensors plus the 0420 and 0430:

DTCs for O2:
P0137
P0138
P0140 what about this one? You didn't list it.
P0141
P0157
P0158
P0160
P0161

**pmolina0436** · 09-13-2008, 06:49 PM

Originally Posted by 0rion

all of them, here's the list for the rear sensors plus the 0420 and 0430:

DTCs for O2:
P0137
P0138
P0140 what about this one? You didn't list it.
P0141
P0157
P0158
P0160
P0161

yea forgot that one..But yea it shows up to !!!should i disable them all???or what do you suggest!!!

**0rion** · 09-13-2008, 10:49 PM

Originally Posted by pmolina0436

yea forgot that one..But yea it shows up to !!!should i disable them all???or what do you suggest!!!

yeah, if you've pulled the sensors go ahead and delete all of them.

**pmolina0436** · 09-14-2008, 12:05 PM

Originally Posted by 0rion

yeah, if you've pulled the sensors go ahead and delete all of them.

thanks for the info...Yea i did disable all REAR sensor , and havent got a problem !!!

**Doug_J** · 09-15-2008, 01:00 PM

The code for my o2's come on some times but I got them turned off i don't know why it keeps coming back, but my diablo lets me erase them. maybe thats a little better or should I just shut up?

**pmolina0436** · 09-15-2008, 03:16 PM

Originally Posted by Doug_J

The code for my o2's come on some times but I got them turned off i don't know why it keeps coming back, but my diablo lets me erase them. maybe thats a little better or should I just shut up?

On the Diablo, when you choose the diagnostics option it does let you erase the codes, but then they would just come back on later...what you got to do is DISABLE the 02 sensor codes...just go to the TUNE IT option...then at the very end of the list there should be a option that says 02 SENSORS!!What i did is diable all of them like they suggested...havent had a problem since!!