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Problem with Code P0133

12K views 1 reply 2 participants last post by  jimmyhsiung  
#1 ·
I need some help with the 1997 C230.

Problem with code P0133 – oxygen sensor 1 before the catalyst slow response.

Day 1 – code came up. Searched BenzWorld and found this code related to the O2 sensor and sometimes the MAF. Cleared the code to see if it came back.

Day 2 – code came up. Installed a new Bosch O2 sensor. Drove the car.

Day 6 – code came up. Grounded the vehicle in the garage. Ordered a new Bosch MAF.

Day 9 – installed MAF (Bosch). Cleared the code. Drove the car.

Day 17 – the return of code P0133. Vehicle is again grounded in the garage pending diagnosis and repair.

We have never had a problem with starting or any smoke of any kind. Should I return the O2 sensor and put in a new one? What would be your recommendations? Thanks
 
#2 ·
There is a fuel supply and vacuum-related /pressure contrl valve on the fuel rail close to BANK 1. Deatach the vacuum hose to blow air into/suck out air (should not be gas) to the valve to see if it works properly. If you could blow air in easily, you got a broken diaphram. Another consideration would be fuel supply. I came upon O2 related codes on M112 before. It turns out to be a faulty fuel filter. R/R that fuel filter and the codes go away. Hope this info could help you.