Is250 Engine Light/traction Off

lwarner1993 · March 28, 2015

Hello,

I have a problem with my IS250 which I am trying to figure out, shortly after buying the car the Engine light/traction/stability lights came up on the dashboard, I plugged it into the OBD and originally found the error to be 'Oxygen sensor bank 1 sensor 1', I took it for it's service and was confirmed that the problem was this and was quoted £335 to replace the sensor, I was told there would be a wait and that the car was safe to drive. Whilst these lights were on nothing in the car seemed to be causing a problem, The car would run fun after erasing the error codes and it didn't come back in for quite a while, a couple of days ago I found that the error had changed to 'p0031' oxygen sensor heater circuit sensor 1 bank 1, I just wanted confirmation that this was infact the same sensor as I couldn't understand why the error message had changed, the old error message is no longer coming back, but unlike what it was doing before the car brings the error back up as soon as the accelerator is touched were before it was only coming up after a few 100 miles, since this new message has started coming up I've also been experiancing very low MPG (use to be getting 30+ now my trip computer is showing 15-16 mpg, there is also a very strong petrol smell, My main question is do I still need to get the same repair carried out as the service center believed it was replacing the oxygen sensor bank 1 sensor 1 or is it another sensor, also is the car still safe to drive or should it be left alone until the repair is carried out?

Thanks for your help

toffee_pie · March 28, 2015

just change the 2 o2 sensors, the car is 2006 and probably on the OEM ones.

It will get worse if you don't replace them.

is200 Newbie · March 28, 2015

Did Lexus tell you to it would be safe to drive?

It may have well been safe to drive but you are coking up your exhaust and any other associated damage in doing so. I know this as when mine went I ran it off and on for a bit as I had to wait for the sensors to be delivered and during this time the exhaust tips sooted up a lot. You will be quoted around £600 if replacing both.

£150 if you order them yourself online and do the work yourself.

lwarner1993 · March 28, 2015

Yes it was lexus that told me it was fine to drive, did you do them yourself? if so did you follow instructions from anywhere or?

Thanks

ChumpusRex · March 28, 2015

http://www.lexusownersclub.co.uk/forum/tutorials/article/225-o2-sensor-bank-1-sensor-1-replacement/

This is the part you need (or you could get the part direct from lexus for a much higher price)

http://www.ebay.co.uk/itm/DENSO-234-9051-Fuel-To-Air-Ratio-Sensor-/301234220773?pt=Motors_Car_Truck_Parts_Accessories&hash=item4622f56ee5

lwarner1993 · March 28, 2015

Actually look's very easy thought it would be alot more difficult than that, could you tell me if this is the same part as I'm from UK was worried as part number wasn't the same but not sure if that is just because its a different part number for UK?

http://www.eurocarparts.com/ecp/c/Lexus_IS_2.5_2006/p/car-parts/car-body-parts-and-car-exhaust/exhausts/lambda-sensor/?710822605&1&f73061d060fd23acd48ecd89f6fe191d14385bb5&000210

ChumpusRex · March 29, 2015

Nope. The part you have linked is the wrong sensor - it is "sensor 2" (after catalyst) You need "sensor 1" (before catalyst).

The sensor is only available direct from lexus in the UK as a lexus branded part.

It is normally considerably cheaper to import a denso branded sensor (denso make the sensors for lexus) from the US, unless you can find a seller in the UK - but last time I checked, there weren't any.

is200 Newbie · March 29, 2015

That's the correct part Mark has shown and a good price

Bank 1 was the easier of the two sensors to do - Bank 2 was a bit more "fiddly" but not much harder. I would suggest that you replace both of them as they will have both been in the car for the same time and theres no reason to think that the Bank 2 one will last (I was told that they are replaced at around 70k miles)

Doing both you will find better mpg and responsiveness. The part above can be used on either bank as the wire is long enough to do this. Follow the step through I posted and you will be fine. Doing it yourself if doing both will save you £450 !! and its not a hard job.