Prius diagnostic mode codes. On my 2012 prius ii i was able to access a diagnostic screen in acc mode by turning the headlightsonoff 4 times while depressing the car button next to mfd screen. The hybrid control ecu may contain fault codes that affect petrol engine ecm operation. This code indicates that too much exhaust gas recirculation egr is occurring the result is an overly rich mix of oxygen in the airfuel ratio and higher engine temps.
Manual fault code extraction. P0402 exhaust gas recirculation flow excessive flow detected. The dlc diagnostic connector is located under the dash on the drivers side.
This trick works on all second gen priuses2003 current. When code p0401 is triggered its because the dpfe sensor found too little recirculation. The best tool for diagnostics is toyota techstream dealer software.
A couple of screens down from the main screen brings up a signals screen similar to that on my 2007 prius which shows the 12v battery voltage. There are a bunch of scangauge xgauges defined for the gen1 prius not quite android user interface but gives you insight into various.