FreeIsGood

Surprisingly, after searching google I wasn't able to fine a diagram because of using wrong keyword searches, eg o2 sensor location. The best drawing for the sensor1 and 2 is here:
https://www.curryacuraparts.com/auto...aust-pipe-scat.

Terminology:
Upstream = sensor 1 or closet to manifold/engine before the catalyst converter
Downstream = sensor 2 = after the catalyst converter
Bank1 / 2 = Some cars have two converters. This model only has one converter so only Bank1.

Purchase price:
sensor 1 is item #18 36531-P8E-A11. or at amazon at $41.22 for OE Denso 334-4727
sensor 2 is item #19 36532-P8C-L21. or at amazon at 24.72 for OE Denso 234-4621

Items needed:
-PB blaster penetrating oil found cheaper at HomeDepot than amazon
-oxygen sensor socket at harbor freights if you got one.
-Get this one: Need the shorter one, 3/8 in. Offset Oxygen Sensor Wrench, $6.99 https://www.harborfreight.com/78-in-...ket-69022.html
-Not this: This long one doesn't have enough clearance https://www.harborfreight.com/78-in-...ket-69022.html
-3/8 12 - 17" Breaker Bar https://www.harborfreight.com/38-in-...Bar-67931.html
-3/8 in. Drive Click Type Torque Wrench https://www.harborfreight.com/3-8-ei...rench-807.html

Optional item:
-Lucas 10003 Upper Cylinder Lubrication & Injector Cleaner 32 oz. at $9. (It's cheaper than the 6oz at $4-5 at local walmart/homedepot/autozone) This can be used 5 times

Instructions:
-Jack up or drive to a ramp. Securely put on stand or tire stops
-Let the engine cool down (1 hour or so)
-Place shop towel/rag under the sensor. Spray with PB Blaster and sit for 30 mins
-Let the engine cool down as you will need to get on top of the engine to reach the sensor clips/harness from the top.
-There's just no room what so ever from the bottom
-Birds eye view from the engine. Squeeze the right to unclip the top wire.
-With the left hand you need to unhook the sensor clip that's mounted to a metal
-Oxygen sensor wire is secured by two plastic clips on a 'stay' Item #20

-Apply anti seize to the thread of the oxygen sensor without getting the sensors
-Hand tighten the sensor first so it doesn't strip the threads. Once hand tighten to as much as possible torque to 33lbs
-Fill up at treat your engine to some Lucas treatment

Karanx7

iTrader: (2)

Good job writing up a DIY!

It's a good guide especially for anyone new to working on their cars. Only thing I would change is to use the Injector cleaner before changing the O2 sensor.

FreeIsGood

I forgot to mention. I was getting a check engine light intermittently along with rough idles at stop. The check engine light would sometimes clear itself then randomly if there's rough idle at stop it would activate. This was going on for over a year. I decided it get to the bottom of this before my next smog test and purchased a OBD2 scanner (ancel ad310)for $35.99 on amazon. It detected a P0131 (Sensor Circuit Low Voltage Bank 1 Sensor 1) and P1739 (problem in 3rd clutch pressure switch circuit). P1739 is another problem for another day.

FreeIsGood

Thanks. You're actually right about doing the injector cleaner first but won't let me re-edit.

FreeIsGood

I had a same link for the both oxygen socket where the 3/8 in. Offset Oxygen Sensor Wrench was wrong above.

This is the correct one: 3/8 in. Offset Oxygen Sensor Wrench
https://www.harborfreight.com/3-8-ei...nch-97177.html

tartilc

Did you notice any improvement in gas mileage? My car doesn't throw a code for the O2 sensor but I read that they can be a long ways from working efficiently before triggering the CEL.

Chojun

Nice job on the write-up. Just a quick question on your P1739 - were you getting a CEL for this or is this a 'pending' code?

FreeIsGood

At first I wasn't sure what was the CEL was about. When I used the scanner last week both code was in the stored code with nothing in the pending. I checked again yesterday and only the P1739 is in the stored code. Nothing in the pending.

FreeIsGood

It's been around 4 days since the replacement and I still have half a tank. It's hard to tell at the moment but the idle is definitely resolved. No more idling where it felt like it was about to stall. I think a fuel injector cleaner should be used 1 - 2 annually.