Hello all, I have my service engine soon light on now and took it to advanced auto to check if there are any codes and he came up with PO174 & PO154.
He tells me that it's the oxy sensor down stream... I have been doing some research on this matter and the net tells me that I have a Vacuum leak. Any help here would be great n tks for all your help here, Bob
Mitsubishi Montero Sport 3.5 with 128,000.

 

Hey Mitch, an O2 sensor is the only issue I have ever had on my 3.5, that was back around 60,000, I'm now around 125,000 as well. I don't remember the code, but that was problem. Lower right I think.. Any luck?

 

P0154.....O2 Sensor Circuit No Activity Detected.......P0174.....System Too Lean

 

I just replaced a completely dead battery and wolaaa, No codes are given now and the truck runs great. I am just wondering about resetting the computer or anything besides the radio code that I had to put in...

 

Is there a way that I can test the oxy sensors ???
I am getting like 8 codes now after the rebuild..

 

Tks. for the info.... Was it in the exhaust manifold cause the cd that I got online is just more of a parts list than anything...

 

UPDATE... Ok, Now I just ran some cataclean and some upper cylinder lube and reset the codes. Ran about half a tank out so far. Now the codes I get is P0174 Bank 2 system too lean, P0154 Oxygen circuit no activity detected bank 2 sensor 1 and P0401 exhaust gas recirculation flow insufficient detected.
Which one is bank 2 let alone number 1 ????

 

See my post about P0173 error and oxygen sensors. I will also write a new post about OBD software (iPhone app) that lets you do extensive OBD2 testing, finding codes and resetting them without disconnecting the battery.

 

I just saw an ad on this page and clicked on it. Worth taking a look! It talks about electronic O2 sensor simulators and extension tubes.

O2 Spacer - Oxygen Sensor Spacer - CEL / MIL Fix - Oxygen O2 Sensor Adapter - O2 Sensor Extender

 

Very interesting Link evan I may have to look into something like that, I wish there was a way that I can test an o2 sensor but I guess I have to buy and replace and see if that was the problem... Tks.