Had code P0155 (Power Steering Pressure Switch Performance) I don't believe that this issue is directly related to the PSPS. This CEL started coming on when I started having weird idle issues. When stationary and the brakes lightly applied (just enough to keep myself stopped) and I release the brake pedal my idle jumps up about 400 rpm. This didn't start until recently when I accidentally filled up with 87 octane (first car in a long time that required it). I did add a bottle of octane booster to help combat the low octane. 2010 Ralliart running GST Basemap v3.1 + Boost pill + K and N Drop in + Flashed S-Sport as well. I drove the care like a granny while the tank had regular in the tank. Has anyone else experienced this issue? Is there anything I should look at in a log? Should I try raising the idle some? I think that the CEL is coming on due to low pressure in the power steering system or high pressure at low load. Everything seems to work perfectly other than this light coming on. If I don't clear it, it will go off on its own but will return. No major boost or vacuum leaks that I can find.

 

Anyone?

 

How many tanks of gas has been through it since the low octane? What is the car idling at without the brakes applied? You may want to reset ECU learning with a fresh tank of gas to get the ECU out of interpolating between the low and high octane maps.

 

It has been at least 2 fillups. When at a stop light with the brakes applied it idles around 750-780. What reset are you talking about? Shell 93 is the only gas I am putting in the car minus the one time I put Shell 87 in and all these problems started. Car drives perfectly normal other than the CEL.

Would any of this possibly be associated with the fact that my original ROM id was 55590011 and I flashed 55590006 GST Basemap?

 

Ok, I reset the ECU. All was much better, car was running smoother, shifting better, and no CEL. After 4-5 starts and driving for around an hour the CEL is back with the same code. I did notice however that the car isn't idling up at all when stationary and turning the wheel in fact it dips pretty far when doing this. Fluid level is right in the center of the min and max levels. I'm totally lost at this point. Guess I will be visiting a shop.

 

Price a new power steering pump, it may be surprisingly cheap.