Cant get this thing to go away! Got my computer chip and it lit up... Replaced the 02 sensor when I did my exhaust went away for awhile and now its back on... Any help would be awesome...

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2005 Grand Prix Base: K&N CAI,, zzp front/rear stbs, Overkilled PCM, 180deg thermostat, Pacesetter headers with full 2.5" custom exhaust, tune, VS cam, TOP SWAP wohoo

please explain said computer chip?...

-- Mon Feb 01, 2010 12:42 pm --

the reason i ask is because if the "chip" your talking about is a "performance chip" all you need to do is remove that. All it is is a bunch of resistors. Your upstream o2 sensor is the sensor that monitors your air to fuel ratio. An o2 sensor is a galvonic battery that creates voltage when it encounters fuel. The more voltage the more fuel present so the leaner the pcm will run the engine. So, if this resistor pack adds resistance and lowers voltage the pcm will dump fuel and most likely cook your cat. When you start your car the pcm self tests the o2 sensor and sees excessive resistance and turns the mil on and sets a code.

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"Dude!, theres enough plastic bags in here to suffocate a nursery!"

Sorry about that... It is an overkill pcm. When the code was set I heard it could be the 02 sensor so I replaced it with a new one and than had a bunch of issues so I went back to the stock sensor and it went back to normal but the code was still present. So I took it to a shop and they said that I had problly fryed my 02 sensor because I had the code showing up while I first installed my new 02 sensor and it like you said, dumped fuel like crazy. So I had them put another new 02 sensor in. The code went away for awhile and has now just showed back up.

I am a newbie when it comes to cars, but I am learning... Powertrain Control Module is the pcm correct? and a performance chip is completely different from that right? If so I do not have a performance chip.

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2005 Grand Prix Base: K&N CAI,, zzp front/rear stbs, Overkilled PCM, 180deg thermostat, Pacesetter headers with full 2.5" custom exhaust, tune, VS cam, TOP SWAP wohoo

ok, so. What your saying is the problem probably isnt the o2 sensor. However. I recommend testing the sensor manually with either a multimeter or a osciliscope. The circuit itself is in question so i would not use a scantool.

-- Mon Feb 01, 2010 3:32 pm --

and correct. Pcm is the computer that controls the powertrain. you do not have a chip. You have a tune. Chips are epicly foolish things designed to take advantage of unfortunate individuals who arent sure of how a vehicles sensors work and destroy their engines and catylitic converters.

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"Dude!, theres enough plastic bags in here to suffocate a nursery!"

It has like 5 wires going through it so I guess I could test all of them. It had to be lengthened to fit the new exhaust so you never know, but I would think something like decreased gas mileage or something like that would occur?

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2005 Grand Prix Base: K&N CAI,, zzp front/rear stbs, Overkilled PCM, 180deg thermostat, Pacesetter headers with full 2.5" custom exhaust, tune, VS cam, TOP SWAP wohoo

it should have four; heated power, ground, high and low reference. just get a wiring diagram from the service manual and test away. you should see varying voltage between the high and low reference wires. but if you have a scope and test it you should see below 500mV but above 100mV voltage should essentially "pulse" or vary at least 10 times in 10 seconds. however the meter that you use will determine how visible that will be, so the higher the baud rate the better (you want at least 3 baud for accuracy in this situation)

-- Mon Feb 01, 2010 7:00 pm --

and you should do this engine at operating temperature with the catalyst at full operating temp as well.

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"Dude!, theres enough plastic bags in here to suffocate a nursery!"