CEL fix no good on 04's

[c5racr1]

well afte trying to find the answer I came up with the problem. the 04 wrx has a different OBD II rear o2 signal than on the previous wrx's . which means in short, when you remove the rear cat, and attempt to compensate for this, getting rid of ithe P0420 code by using a CEL fix, you get a CEL P0139 (slow sensor speed).
Through trial and error I found this out. Pony express, and caspers don't have the answer yet and will not for a while, so I can 1 get the pcm re-flashed or 2 live with it for now. since I plan on further mods, I will sit on It for a minnute
hope this helps!

[crampers]

Thanks for posting this info. I have an 04 and plan on modding the exhuast by summer end. Hopefully by then some of the companies will figure it out. Also, you can talk to some of the engine management shops (Cobb, etc). They may have mods to get rid of this soon if you purchase their reflashes (I know they already can get rid of CELs on older rexes).

C

[Dream]

I installed a Prodrive axle back and threw a cel on my 04!!

[ryland]

Originally posted by Dream
I installed a Prodrive axle back and threw a cel on my 04!!

And there is a 99.9% chance that the axle-back didn't cause it!

[God]

Originally posted by crampers
Thanks for posting this info. I have an 04 and plan on modding the exhuast by summer end. Hopefully by then some of the companies will figure it out. Also, you can talk to some of the engine management shops (Cobb, etc). They may have mods to get rid of this soon if you purchase their reflashes (I know they already can get rid of CELs on older rexes).

C

My downpipe has been tested on 04 models. No CEL, no cats, no problems.

[pilotdoc]

Try using a 1Mohm resistor on the O2 sensor wire. You can find this at the ECU or at the sensor itself. Basically it's the same as the Pony Express fix without the capacitor. With the capacitor, will throw a slow-response code.

[MustGoFast]

and with just the resistor it wont get enough voltage and it will still through p0420

[pilotdoc]

the resistor has worked for me. No codes. 2.2kOhm resistor was too small though, that resulted in an 0420 code.

[Shibby]

will my TurboXS RFL-Ti axleback im about to purchase throw a CEL? How could it?

[frisco-wrx-dude]

I have a '04 WRX and will be getting the uppie and Down pipe (tommorow). I'm just wondering u said to use the 1Mohm resistor (instead of the 2.2k for hte '03) will work.

its a 1Mohm but wut about ?watt? (ohms law). Have anyone else done this and has it worked for you already?

THanks

[pilotdoc]

hi frisco, sent you a pm. but it's a 1/2 watt IIRC.

[frisco-wrx-dude]

but it looks like the 1/2 watt 2.2k ohm is for the '03 wrx and not for the '04. I'm referring to the '04 and ur note earlier about using a 1Mohm (not the 2.2Kohm)

Thanks

[Raz]

So anyone come up with a solution yet?

[pilotdoc]

Hi, my fix is for the 04. It works for me. Just to reiterate - 1Mohm resistor, 1/2watt, in line with the sensor wire from the rear O2 sensor. You can tap under the car or at the ecu.

[Raz]

Originally posted by pilotdoc
Hi, my fix is for the 04. It works for me. Just to reiterate - 1Mohm resistor, 1/2watt, in line with the sensor wire from the rear O2 sensor. You can tap under the car or at the ecu.

What DP are you using, and how long has it been on?