Quote:
Originally Posted by elp_jc
Thanks buddy. Pretty complicated to just remove indeed.
Hey, this crap was invented when we had carburetors, since during deceleration, fuel was still sucked along with the air (engine is an air pump), and needed to be burned before hitting the cats. But why the hell we still have that crap on fuel-injected cars? Is it really needed? Just curious of your opinion. Remember removing all that crap from my FI bikes, and plugging the ports. Never a CEL, but they were obviously A LOT less complicated than cars  . |
On these cars the fuel injectors are turned off on deceleration, that way no fuel hits the cats. It will resume injection at idle or before depending on the circumstances. Even my 1990 7 series turbo does this with the prehistoric Motronic 1.3 ECU, which is one of the first adaptive ECU's ever offered on BMW's, employing static correction factors and other features that we commonly see in today's ECU's.
I turned off my secondary air system for a couple of months to get rid of the loud noise at startup (which I actually like..). Last week I turned the system back on and it began throwing code P0056 within a few days. The code read out with my BMW laptop is:
lamdasonde endstufendiagnose heizung nach kat bank 2
beheizte lamdasonde heizungssteuerkreis (bank 2, nach katalysator) - fehlfunktion oder leitungsunterbrechung
In English this translates to:
"oxygen sensor heater after cat diagnostic output stage bank 2
heated oxygen sensor heater control circuit (bank 2, after catalyst) - lack functional or line interruption"
Ironically enough, a client of mine with a 2011 M3 coded for the exact same code except it was P0036 (bank one instead of bank two in his case). His code would come on immediately after clearing it. Turned out he bumped an o2 sensor and bent it from a curb at the gas station.
In my case, nothing has changed. I am thinking that the sensor has either become fouled up from the cold start being disabled, or it has just failed for whatever reason they fail. I cleared it and it came back within a couple of days. Then it cleared itself, and yesterday after picking my car up from the bodyshop (LCI trunk and tail lights retrofit), it coded again.
Remember that even when the cat efficiency checking is disabled in the code, the car will still code for errors with the post cat o2 sensors as it is in both of these cases. This means if the heater circuit goes bad or if the sensor is damaged, a CEL will still illuminate.
I am going to take it to the dealer and they will probably replace that sensor and send me on my way. I'm going to leave the software in there otherwise it will have that code plus two more for cat efficiency. I figured it's best to give them the car with the problem isolated as much as possible because they might try to blame the high flow cats if it comes in with all three codes.