I have just had 195000km service on my Mitsubishi Triton 3.5 Ltd V6. They replaced my air filter and I now have a check engine light. Code P0433 on OBD scanner... replace O2 sensor, exhaust leak. No extraneous noise from exhaust. Could the filter cause this please? I had no problem before this. I am in Australia

  • Welcome to Motor Vehicle Maintenance & Repair! Oct 8 at 22:01
  • Did this happen immediately after getting the filter changed? I.e. in the way home?
    – HandyHowie
    Oct 9 at 7:11
  • When I went to leave the workshop it was on, the mechanic cleared the code and on the way home it returned. I cleared the code & it reappears every time I restart the engine Oct 9 at 8:25
  • There seems to be conflicting definitions of OBDII code P0433. Most websites define it as "Heated Catalyst Efficiency Below Threshold (Bank 2)", while some others "EVAP System Purge Control Valve Circuit – Malfunction."
    – Carguy
    Oct 10 at 7:26

Potntial cause of a P0433 code could be a defective catalytic convertor. It is triggered by the upstream and downstream oxygen sensors indicted the same the data on oxygen concentration in the exhaust.

Other causes include a exhaust leak before the catalytic convertor, misfires, defective oxygen sensors,MAP and MAF sensors. Another possility could be electrical in nature such as burnt or damaged wiring or connector in that area.

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