Hi everyone,

I have a 2004 Concorde with a 2.7 liter engine. I have been, on occasion, experiencing a loss of power where the car struggles to reach the speed limit. It happens sometimes at low speeds, but once it passes the car is fine for a few days. The code reader tells me that the #2 o2 sensor on bank 2 is the reason for the engine light.

First question is, how many catalytic converters does this car have? I see one on either side of the engine between the sensors, and then what appears to be one under the car (about midway) before the muffler. I have heard the term "pre-catalytic converter" before, is that what the two small ones between the sensors are?

Second question is, would it be safe to assume that it is the smaller converter on bank 2 since the pre sensor doesn't give off a bad reading, but the sensor after does? Seems to isolate the problem, and I doubt that the sensor is faulty, because I don't think that would cause the lack of power.

Third question, has anyone changed these smaller converters before, and if so, how much do they cost, and how difficult are they to change.

Sorry for the long post, and thank you all in advance for any help or advice you might have.

Also, in case it helps with anything, the codes I get are as follows:

P0158 (02 circuit high voltage (bank 2, sensor 2)
P0440 (evaporative emission system)
P0441 (incorrect purge flow)

It makes sense to me that the last 2 codes could be cause by the first one, but I would appreciate some other opinions on that one. Thank again.

 

2 converters replace the down stream o2 sensor after the cat both of them dont use BOSH and the evap codes have nothing to do with the o2 sensor it would be more then likely a cracked hose some where

 

I see, thanks. So you don't think that the Cat is the problem? I was hoping that it would be the sensor(s) because they are cheaper and easier to change. I just didn't think that a sensor could cause the problem I was having with the car's occasional lack of power.

 

unless u have clogged up converters I doubt it plus they would throw a rich or lean code on top of the o2 sensor codes if the cats were bad.

then again any of the above might not have a single thing to do with your issue as well.

 

Alright, then maybe I will start with the sensor, and go from there. May I ask why you recommend against Bosh? Do you have a prefered brand of sensor? And what can I expect to pay for a good replacement sensor?

 

use factory 02 sensors. There are 2 different kind of sensors wide and narrow band U cant tell by looking at them its a PCM software controlled deal so bosh has almost never been the right setup. I am having to replace a PCM for a lady because some guy that has no clue replaced the o2 sensors with BOSH ones and it shorted out parts of the PCM now with fuel injector codes and IAC codes .

 

Alright, thats all good to know, thanks.