I am experimenting a bit with the catless down pipe (please don't &#128293 I I used all kinds of spacers, it works... sort of...

I keep throwing pending code P0141 for secondary sensor heater but ONLY when I go WOT.

1. Question: why does WOT triggers P0141? normal driving no codes pending or permanent with CEL. We tried another O2 and still the same behaviour, normally o2 spacers are adjustable... getting the sensor "closer" triggers p0420 only... getting it a bit farther away triggers p0141 and even farther p0140 & p0141.

2. Do "Pending" codes affect drivability in terms on fuel trims or injector pulse? Or only "confirmed" codes?

Everything else is fine and drives perfect, it even reaches full readiness after three drive cycles...

 

When you go WOT, air to fuel ratio goes rich, so this maybe the reason. Normal driving is fairly lean especially with direct injection and super lean burn mappings.

 

I see... so is too hot or too cold of a temp for the sensor the problem?

JC

 

I was thinking that there is a lot more unburned fuel (from running rich during WOT) in the exhaust stream that the sensor detecting.

 

Thanks cerenkov, but wouldnt that trigger P0420?

or why P0141? Which apparently is unrelated...

 

You're right, sorry didn't read your first post closely enough. I'll think about it some more.

 

Thanks! I am really looking to get to the bottom of this...

 

Is it possible that you damaged a wire and when going WOT the engine rocks causing the wire to move and touches something and shorts to ground?

 

not really... we even tried another O2 same results... and if we reinstall without O2 spacer we get the "normal" P0420.

 

Hmm I'm getting the P0420 code from installing a new downpipe. I was thinking that it was the sensor and was about to buy one but now since I saw that you have that problem even with a new sensor.
I also get this when I go wot. Don't know if this code will cause any damages.

 

It is not at all uncommon to get O2 sensor codes when you install a cat-less down pipe. Only option is to ignore the light, or have a Manic tune installed to remove the code.