P0136 02 Sensor Circuit Malfunction, and P0141 Heater Circuit Malfunction

[jpmad4it2]

I have these 2 error codes on my 172 cup:

P0136 Oxygen 02 Sensor Circuit Malfunction / Low Voltage (Bank 1, Sensor 2)
P0141 Oxygen 02 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

I've been here http://www.obd-codes.com/ to check them out, but it doesnt really mean a lot to me. Can anyone put it in simple words? I noticed that I was getting a stupidly low MPG last winter - like 9MPG some days, along with the car struggling to start. Could all this be related? What can be done to fix the problem?

Any help is appreciated.

 

[Dunn]

New lambda before the cat?

 

[jpmad4it2]

So these codes point to the lambda sensors ? I did use to have a decat fitted, and the guy who removed it and put the original piece back on moaned that it was a difficult job. Maybe he's not done the job right.....or the sensor it fooked like you say.

 

[Dunn]

Yes i would say so

Mine is also goosed after having a decat and now swapping back to standard
Doesnt run great from cold, usual symptoms are it feeling like its accellerating by itself and hesitating when cold but fine once warm

ill get my code reader on mine tommorow to see if i get similar codes to yours

 

[jpmad4it2]

Yeah same symptoms as mine. Ok cool - let me know if you do get similar codes? The 136 code causes the 141 code I think.