Oxygen Sensor On Is250

[bally k]

Hi All,

I had the dreaded "check VSC" message together with the traction control and engine light come on today on my 55 plate is250. The AA hooked up their diagnostics machine and it came back with P0031- Oxygen sensor(bank 1, sensor 1) and P0138 (bank 1, sensor 2).

Can someone tell me if it's common for both sensors to go or is it likely one is triggering the other? i.e. if I fix P0031, this will resolve both?

Can someone also tell me if these two sensors are the same part and fitted pre-cat? There is a huge difference in the cost of a pre cat sensor compared to post cat...

Finally, can anyone recommend where to order these from and even get this fitted in the London area?

Thanks in advance for any help you can provide.

[ColinBarber]

it is highly likely that the fault associated with P0031 is causing P0138 as well.

P0031 is related to the heater in sensor B1S1 which is upstream of the cat. This is normally because the heater has burnt out in the sensor which is quite easy for the ECU to detect and therefore is rarely a false alarm.

P0138 is related to readings from the sensor downstream of the cat. It is probably being triggered because the engine isn't being fuelled correctly because of the main issue rather than it being an issue with the sensor or the cat.

The pre cat sensors are air/fuel ratio sensors rather than a normal O2 sensor which is why they are expensive. Only replace with a Lexus/Toyota genuine sensor, or the Denso OEM equivalent.

[bally k]

Thanks - That's very useful info. It's going in today so I'm going to ask them to change B1S1 ONLY and check to see if this resolves the issue. Fingers crossed!

[greg1978]

Hello

Is anybody can help me please

Does anybody know part no. For oxygen sensor B1S1

For IS 250 2006 reg

Thanks