Kenpo_S2000

I have heard from other members that the Secondary 02 sensor is just a sensor and has nothing to do with air/fuel mixture. I am talking about the sensor that plugs into the catalytic converter.

I went to my local Honda Mechanic who told me the secondary 02 has a lot to do with the mixture of the fuel/are mixture. When I told him that I heard it doesn't matter if the sensor is hooked up or not because of what I read on here, he got kind of mad and told me not to believe everything I read.

Is this correct or not?

I installed the Invidia test pipe with welded 02 cheater. The CEL still came on and said P0141 02 Sensor Heater Circuit Malfunction Bank 1 Sensor 2.

The 02 sensor I am using is an 06 sensor I bought from a member on here. Could that cause a problem with my 01? I thought all sensors should be universal especially the plug in OEM one.

Please help me out or anyone that wants to input.

THANK YOU!

milkbubble

The secondary O2 sensor is used to detect the catalytic converters efficiency. The primary is for air/ fuel. Im not sure what you mean by "hooked up" but it does matter and must be connected electrically. I have also used anti-foulers when I had a test pipe with great results.

I would go to www.hondaautomotiveparts.com and compare part #'s for the secondary O2 sensor for the years you are asking about.

Honda_mann

An engine diagnostic system includes a catalytic converter and an outlet O.sub.2 sensor. The outlet O.sub.2 sensor generates an outlet signal that is based on an oxygen level of exhaust gases exiting the catalytic converter. A controller adjusts a secondary fuel trim based on the outlet signal. The controller indicates a fault status if the secondary fuel trim has achieved a fuel trim limit and the outlet signal is out of a diagnostic range.

Fongu

The secondary O2 sensor is used to make sure the catalytic converter is working. So technically, it only for emissions control, but if it is not there or out of spec the ECU will report a CEL code.

The primary O2 sensor in the header is used to control the air/fuel mixture in closed loop, i.e. under partial throttle. Our ECU uses the primary O2 sensor to adjust for lean/rich air/fuel ratios and stores a short term fuel trim value. Eventually, the short term fuel trim is averaged into a long term fuel trim value. The long term fuel trim value is used to adjust the air/fuel ratio in open loop, i.e from around 75% to WOT. In open loop the primary O2 sensor doesn't have any direct effect on adjusting the mixture, just the long term fuel trim to adjust for things like environmental conditions, type/quality of gas and any minor engine differences (or minor mods like I/H/E). The short and long term fuel trim adjustments is what learns out badly tuned piggybacks that also adjust fuel during closed loop operation.

The secondary O2 sensor measures the mixture after going through the cat. If the cat is working there is a difference in measurements from the primary to secondary O2 sensor.

Kenpo_S2000

[QUOTE=Fongu,Jun 12 2007, 04:29 PM] The secondary O2 sensor is used to make sure the catalytic converter is working.

Billman250

The code you have P0141 is not typical for an inactive cat P0420

You have a bad/incompatible/miswired o2 sensor.

Kenpo_S2000

Thank you that is what I wanted to know. Please answer this for me then.

If I get a good 02 sensor put it in, everything should be fine then?