Ladies and Gents, my pos is throwing a p1121 code at me.

From what I've read, this is a bank 1 rear 02 sensor heating circuit code. Can anyone confirm this first off?

Aside from just redoing the connections to the 02 sensors, in the engine bay and making sure the sensors are tight in the exhaust, not much else to do right?

I'm guessing its just going to be an 02 sensor replacement?

thanks in advance for all the help.

 

Oxygen Sensor Heater (#1 after Catalytic Converter)
Exactly as stated in "Porsche 993 the Essential Companion" by Adrian Streather.

 

Thanks Alan

 

I threw some O2 sensor codes and I asked here, and from responses and reading prior threads I concluded that it was my MAF. The car throws the O2 sensor code because the MAF was not reading correctly or screwing up the air flow and the O2 sensors compensated for the air/fuel mixture past their acceptable limits and hence the CEL from the O2 sensor. I cleaned mine with CRC MAF and it idles and drives much smoother and after clearing the codes I have no new codes in 400+miles.

 

interesting.

The rear 02 sensor is basically just for catalyst efficiency, so I wouldn't think it would derive from the MAF, especially just on one bank.

That said, stranger things have been known to happen and popping out the maf is no biggie so I'll do that for good measure.

A new rear 02 is only $45 though, so I'm not sweating throwing some parts at it.

 

The book also states that this code is a failure type 3 (Input too low or out of tolerance low).

 

That sounds like a "universal" part. You'll get to cut/solder the leads from your old sensor to the new one. Personally, I don't solder so well so I buy the OEM sensor w/ the Porsche plug already installed for about $80.

 

Does it come back after you erase it? Mine had it when I bought it, I erased it and it hasn't come back in 18 months/4500 miles.

+1 on buying a Bosch OEM replacement. But before you do that, see if you can swap the rear O2 sensors and whether the ECU will throw a code on the other side.

 

actually, amazon has a sick deal on the oe fitment unit with the plug

http://www.amazon.com/Bosch-13577-Ox...ies/B000BZEIBG

The code did come back ilko, but yeah probably a good call to swap side to side.

Thanks guys

 

Amongst a myriad of other things (i.e. oil spillage during filter removal)

Mike

 

Well quick update. Undid the connector, sprayed it with electronics cleaner and pulled the sensor out of the exhaust and just cleaned it with a dry shop towel. Reassembled and no ce light in 30 miles and 4 key cycles...we'll see what happens

 

I see that Bill's tribute to your detail job is gone....