OBD II code-what to do? Help Fast!

[FASTSPOOLINGST]

I have posted this in problem diagnosis probably 2 times and yet, no one can answer my question.

i get a check engine light, so i hook up the OBD II tester, and it says

Oxygen Sensor (Bank 1 Sensor 1)

Does this mean that my O2 housing O2 sensor is bad, or the one by where the cat used to be. Because on my turbo timer I am reading O2 sensor voltage. I am also getting the same gas mileages as before it popped up. The weird thing is, that after the car is warmed up for a while, if you shut the car off, then erase the fault code, you can then drive it around all day and the light will not pop up again. It will only pop back up after the car has been sitting over night or for a few hours to cool down. What gives? someone help me asap please!

Thanks in advance

 

[LightningGSX]

When you have a problem the light just doesn't know it and turn on.You have to meet certain criteria and go through a certain drive cycle before it will set the code.What does your o2 voltage look like? I'm thinking its the o2 sensor heater(which comes on when the car is cold), so you'll probably need to replace your pre-cat sensor.

 

[FASTSPOOLINGST]

The O2 voltage is withing the normal range that is in the Apexi turbo timer instructions for idle fluctuation. I think you may be correct. Check these out, these are the exact code numbers and what the code reader said was wrong.

P0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)

P1400 Manufacturer Control Auxilary Emissions Controls

P0420 Catalyst System Efficiency Below Thresh hold (Bank 1)

I did not have any of these problems until after I swapped to the EVO III Mani, turbo, and O2 housing. I am thinking that since the O2 housing and turbo are so much bigger than the stocker that the system is reading it all whacky and the light popped on because of that. Maybe the last code is due to the cat being removed.

Tell me your ideas based on this. I also went to the Mitsu dealership and asked their tech guys, they said that it was probably due to the cat being removed, but when i still had my stock turbo and o2 and mani on, i still had the cat removed and it never popped up. WTF????

 

[LightningGSX]

P0420 is definately from removing the cat.I guess you should check the wiring too, you may have pinched or broken a wire when you swapped stuff.Check for continuity across the heater inside the pre cat o2 sensor, if none replace the sensor.I would almost bet its the sensor, they can get pretty fragile.BTW it could take weeks/months for the ecu to report a catalyst efficiency problem.You have to go through a somewhat complicated drive cycle for OBDII to monitor catalyst efficiency, which depending on your driving trips/style could be a while.

 

[LightningGSX]

PS I would recommend grounding the the post cat sensor signal wire, which will then read 0 volts and should simulate a perfectly working catalyst.

 

[FASTSPOOLINGST]

Thanks for the info. I will try it out, since nothing else seems to work. I'll post the results later on tonight after I am finished and test it out.

 

[LightningGSX]

Make sure you only ground the signal wire(there is only one).

 

[FASTSPOOLINGST]

Do you happen to know what color the wire is? Where i can get a wiring diagram for it?

 

[LightningGSX]

I don't know the color.Do you have a multimeter? If you do, ground one of the test leads and, with the engine running, find the wire that jumps around between 0 and 1 volts.There should be 4 wires, 2 are ground, 1 signal , and 1 heater.