We have just fitted 22641AA042 Front AFR Sensor into a P.WRX WRP10. The vehicle came in with the engine light on which indicated Front O2 AFR sensor.

I will be detailing pics of the install for those of you who want an insight into the installation process.

Pics of part to be installed:



1) Unplug the sensor harness. Plug is located on the driver's side of the engine bay close to the factory boost solenoid.


2) Remove the factory air ducting. This is held by 2 size10 bolts.



3) Unclip the factory harness from the metal support. This is located beside the driver's side coilpacks.


4) Jack the car up or use a hoist if you have access to one(makes life a lot easier, but in this illustration, I had the WRP10 jacked up on stands).

5) Remove the under cowl. There are 2 size12 bolts on the rear, 3 size12 bolts on the front and 2 corner plastic clips.
Front bolts are located in the circular indentation. There are 3 of them:

Rear bolts are located at the back middle section. --- Dont forget the 2 plastic clips:

6) Now that you are able to see the Front AFR sensor on the drivers side of the engine, remove the clips on the plastic cowling on the right side of the sensor so you will have more room to acess the sensor and remove it. Use a 22mm crow foot if you have one or a close ended spaner (use a 6-sides one instead of a multisided one) and remove the sensor counterclockwise.

Below are pics for illustration:





7) Once you have removed the sensor, replace the AFR O2 sensor with a Genuine Subaru item. The genuine Subaru item has anit-seize already on the threads. Do not over tighten sensor. Just tighten it with the closed end spanner or crow-foot and you do not need to apply excessive force to tighten it.

Below are pics of the old faulty sensor on the right that I removed vs the newly updated Genuine Subaru item (22641-AA042) we carry on the left. The newer Subaru 22641-AA042 has better insulation than the previous part. Note that anti-seize is already applied from factory.


New Sensor is now in:


8) Once you have fitted the sensor retrace steps 7-1 and you are done.

I hope that the above will give you an insight on how the Front AFR O2 sensor is removed and replaced on a GD WRX/STi.

Difference between faulty coilpacks and new coilpacks:

We have just re-tuned Simon's car ready for his round of 0-400m today. Couple of months back, the car had a misfire above 5000rpm where we reset trigger levels on the Vi-pec to dismiss the tune. This resulted in a 335hp run.

However, at the last Kwinana drags, he complained of a misfire up top again which only gave him a best time of 12.7s.

Yesterday, we put his car on the Dynapack for a retune. This time round, the car hit 330hp max. After about 3 runs, the car started misfiring again, dropping power to 308hp. We tried to reset voltages and dwells, as well as trigger levels, but there was no improvement.

We then proceeded to change the Ik22 plugs and new coil-packs. Problems solved!! You can see these products at our Spark plugs thread ( http://www.perth-wrx.com/vb/evolutio...ark-plugs.html ).

Below are pics of 2 of the coil-packs taken off Simon's engine:



New Coil pack we put in:


Below is how Roughstilin's car performs when it misfires:


Below is the result of today's tune and our tune is health-proven. Stock STi 2.0 engine is still mint, producing awesome power boosting at a max of 1.85 bar of boost after all the events he has been to.

We will now be stocking the Genuine Subaru O2 AFR Sensor 22641-AA090 which is a common wear point on the BE and BH Libertys.

P.WRX price is $280.

Just a quick note, as I always forget to log the DTC codes. I will update all DTC codes that I encounter, rather than scramble for the service manual and part numbers, everytime the Carman diagnostic picks up the code.

GD WRX/STi:
P0031 --- Front AFR sensor heater circuit -- O2 sensor 22641AA042

Hey Mao,

how much for a rear o2 sensor for a 2002 STI?

Cheers

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2005 WRX STI

Hi Brett,

Rear O2 Sensor --- 22690AA501 in stock -- $250. Will fit it in for free and rid of CEL before charging.

Cheers.

Brilliant, free on Monday and I'll pop round? Cheers


Sent from my iPhone using Tapatalk

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2005 WRX STI

Yup, just pop by any time before 3pm and we will have it sorted out in half an hour.

Cheers.

Sweet, cya then

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2005 WRX STI