Oil Pressure warning light

[Jager]

The forum is all over this issue!! Yes, while the car is running (and warmed-up) remove the oil fill cap. If it is difficult to remove the cap (high suction) and the car almost stalls when the cap is removed (while your oil fill sounds like a shop vac), you most likely have a bad AOS. A bad AOS will give you the same alarm codes you have (I’ve been there). As a result of a bad AOS oil will get on your O2 sensors and possibly mess those up, you might have to replace them. If you have a bad AOS I would replace it first, reset alarm codes and see what happens.

Jager

[JFP in PA]

This is exactly what I mean about O2 codes and interpreting them; P1126 means the sensor cannot richen up the mixture enough to get the fuel mix back inbounds, probable causes: low fuel pressure or vacuum leak. P1133 indicates an overly lean condition (below lower limit for mixture). P0450 indicates the EVAP system at the fuel tank is giving an “implausible” pressure/vacuum value.

The first two point to an overly lean mixture, probably caused by a vacuum leak in the EVAP system in the passenger’s side wheel well, next to the fuel filler, as indicated by the third code. There are multiple valves, sensors and a bunch of vacuum lines on the EVAP system (which captures and allows the engine to consume fuel vapors from the tank). Anyone of them can be the culprit.

But in any case, your O2 sensors are fine.

[Boxster TK]

All,

As a follow up, replaced the AOS today for $200 Canadian (tax in) and everything is good to go. No more CEL (related to O2 emissions/sensors etc), no oil pressure light flickering at low RPMs.

There was a tear in the Diaphragm inside the AOS...once replaced, the whinning sound was gone as well at 2200 RPM...

Thanks for the help!

Tk

[Jager]

Fantastic! Double check the oil level on the dipstick and on the instrument panel, the oil level should be between the two marks, don’t over fill.