I have three engine code on, two for two O2 sensors and one for EGR Value ($350). My mechanic is suspecting a short somewhere. My O2 sensors give almost 0 home resistance when it should give about 6 ohms. My question is this, repair is going to cost me quite a bit esp that the car is running 100% OK, it is just the checkengine light on, that I need to take care of.
Is there an easy and standard way to find short in the circuit? My car did give me some indication of it. If I dont drive it for a day or two, it might not start because of almost dead battery.
Can if fix the EGR value which is kind of expensive?
The car is MAZDA 626 year 2000
this page lists side affects of bad EGR value, my car has none of these. No rough idling (800 rpm idle), great fuel economy, no knocking, no overheating.