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does anyone still have the original picture showing which wire to cut and which wire to splice that is the "free" repair to correct MIL P0161 for 2002 ? The picture link has seemed to expire and i cant find it anywhere.
 

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does anyone still have the original picture showing which wire to cut and which wire to splice that is the "free" repair to correct MIL P0161 for 2002 ? The picture link has seemed to expire and i cant find it anywhere.
The pic no longer exists, I even tried searching too. However, I found the pin outs for 02+ and can easily walk you through the mod. Here's the pin out.

**what you do is cut B2S2 red/white stripe heater wire before the ECU. Leave yourself enough wire so that you can splice the remaining red/white stripe wire that goes to the ECU(which is now just a pigtail wire off the ECU connector) to the green/black stripe B1S2 heater wire(this is an inline splice, so the ECU will sense B1S2 and think B2S2's heater circuit is ok because the red/white stripe wire is spliced into it). Then you can just tape up the red/white stripe B2S2 wire that you cut which came from B2S2. Hope that helps and makes sense, lemme know if not.
 

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Having some trouble finding the right part numbers for my o2 sensors. I want an aftermarket set, was quoted $324 for the two I need at the dealership. Please help me to identify the correct aftermarket part numbers. Was looking into Bosch. If there are some better alternatives, please advise. Thanks!

2003 IS300:
Bank 1 Sensor 1
Bank 1 Sensor 2
 

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Well I finally got round to replacing one of my O2's (B1S1) with the Denso part 234-4209. The wires color codes matched up fine. Note the Denso has crimp connectors in the box, When I tried to solder I found out the wires do not solder well, the wires do not want to wet and are probably not a copper alloy.
So just crimp them in to the original harness.
 

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There are thick ones that are really plug n play and do not need repining or splicing. They are actually not that expensive they are around 80 something dollars


PREVENTATIVE VEHICLE MAINTENANCE
 

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I would be careful with the simulators. I had one on my car for years and it worked fine. I had actually forgotten that we installed it. My car recently needed some major repairs (cats and new O2 sensors) and that simulator caused a lot of confusion. It caused the computer to keep throwing O2 sensor codes after all the sensors were replaced. The shop couldn't figure it out. It wasn't until I was looking around here and saw some posts about the simulator that I remembered that my car has one. I thought it was a long-shot, but told the shop about it. After the removed it, the last code cleared. They "shamed" me telling me that I could have ruined my computer...and I am $2200 poorer and spent 10 days without a car. I suspect given the age and mileage of my car, the cats needed replaced anyway, but the extra trouble cost me an extra $600. The O2 sensors are relatively cheap...not much more than I recall paying for the simulator. I wish I had been smart enough years ago to replace the sensor, rather than put the simulator on.
 

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How did you guys get b2s1 sensor out? Trying to do it with the socket seems inpossible. Do i need to use a wrench for that one?
 

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You can unplug both B1S2 and B2S2 with no problems or effect on performance besides a CEL. Those two sensors only monitor cat performance, that's it.
On some OBD-II vehicles, the post-cat (S2) o2 sensors are indeed used for fine fuel trim corrections, not only for the cat monitoring. According to some sources, some Toyotas are affected.

Is there any trustworthy evidence that it's not the case with our car?

I read many o2 sensor related discussions here and saw forum members reporting better performance and fuel mileage after fixing S2-related codes like P0161 or P0141 by replacing the affected sensor. How could this be explained?
 

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Here's my problem: All sorts of codes (6 total...)
P0130 - B1S1 Sensor Circuit Malfunction
P0133 - B1S1 Sensor Circuit Slow Response

P0141 - B1S2 Heater Circuit Malfunction

P0150 - B2S1 Sensor Circuit Malfunction
P0153 - B2S1 Sensor Circuit Slow Response

P0161 - B2S2 Heater Circuit Malfunction

It seems to me like there's a pattern here - both upstream sensors show a malfunction and slow response. Both downstream sensors have a heater circuit malfunction... Could this be because of something else? The heaters have fuses, right? Does anyone know where they are on this car?

I don't want to replace 4 oxygen sensors if I don't have to. I got the car a year and a half ago, and it had O2 codes then (less, forget which ones), at 126k. It has 172k now, and the 6 codes. I'm just afraid replacing all 4 sensors is a waste if I don't have to... ya know?

Any help is appreciated!
Old thread revival!!! Has this problem been fixed?? If so, how?
 

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I've got that, but there is limited space to work.
You can use a wrench, then lock another wrench on it to use as leverage. You'll need to disconnect it and slip the ring side of the wrench in.
 

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I think it should be noted that on both banks, sensor 1(precat, upstream) is the one that will effect performance. B1S2 and B2S2 (post cat, downstream) really only need to be replaced if you live in an emissions county.

Also, when it comes to getting these little b****** off, PB Blaster seemed to work wonders. Also, my local Autozone had a o2 sensor socket set that they rented out to me. This made it super easy for me. Especially B2S1(beside firewall).
 

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If you can wait a few days, order from Rock Auto, https://www.rockauto.com/ Then enter Brand, model, year etc. The daily driver section has many brands. Denso and NTK/NGK are OEM for Lexus/Toyota and other Japanese brands. They are priced from $50-67.00. It is important that get you exactly what you need. your code reader will tell you the bank 1 or 2 and sensor number 1 or 2. The prices from Rock Auto are the best. Look for a 5% coupon on the internet. It is important to check the connector for the perfect match online. Double checkRock Auto has a wide shot and closeups in the info section. Warning, don't open the plastic package until your sure it matches the connector of the unit taking out. It is not returnable if opened. You will need a 02 special socket. Pull negative ground off the battery. Read all the valuable information on the forum. Look at Squareback the first for the photo. That is the best illustration you can have. Look at Chrisfix on youtube:
 
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