Got my first CEL today

[Seerlah]

It was code P0420 bank 1. I already cleared it, but it will be back. I know is was because of my HFC and read a thread how I can do the anti-fouler mod to the 02 bung to trick the ECU. My question is, would I eventually get the code for the secondary 02 sensor? Has anyone ever received that code for the secondary 02 sensor for the same reason? If not, I will just do the mod for the primary sensor. Thanks!

16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold
Possible Causes
Leakage in Intake and/or Exhaust System
Catalyst faulty
Oxygen Sensor(s) faulty
Oxygen Sensor(s) Control faulty
Possible Solutions
Check Intake and Exhaust System for Leaks
Check Catalyst
Check Oxygen Sensor(s)
Check Oxygen Sensor(s) Control
Perform Oxygen Sensor(s) Aging Check

[Ewok_Fetus]

What mod for the primary sensor... Don't touch that one... Get a spacer and put it on the 2ND sensor...

[Seerlah]

Isn't bank 1 the primary sensor?

[audinutt]

no, bank 1 is refering to the bank of the cylinder head, on a inline engine (like yours) you only have bank 1. on a V engine (two heads) you have bank 1 (the head with cylinder #1) and bank 2.

Your code is for bank 1 catalyst. efficiency. that just mean catalyst efficiency, it's not pointing to sensor 1 (pre cat) or sensor 2 (the one you need to mod!)

-richard

[boostedup]

i heard on the 01's you couldn't do the anti-fouler mod, because the CEL will not go away.......

[Seerlah]

Sorry for the misunderstanding. I thought that bank 1 was referring to the primary 02 sensor. I now know it referrs to the cylinder head bank. Thanks for clearing that up. Going to do the fouler mod asap.

[Nebone]

I've had that code forever with my HFC. Let me know how it turns out in the long run.

You shouldn't get a code for the secondary O2 sensor unless your break it; the mod will not affect it.

FYI: Only touch the after-cat (post-cat) sensor. Leave the front one as is.