Help shop needs help 328is -check engine light

[winfred]

that's why it's probably not the sensors, if you replaced one front sensor id replace the other so you are not fighting the new sensor out reading the old one and get the codes reset, see what happens and how fast, immediately id be checking the wiring, shortly id be looking for vacuum leaks (usually it's the oil vapor separator under the intake

So if they dont come on till 600 why does the light come on imediately. Seems like the car would have to warm up before the circuit would check the gases?

[tonyvt328is]

that's why it's probably not the sensors, if you replaced one front sensor id replace the other so you are not fighting the new sensor out reading the old one and get the codes reset, see what happens and how fast, immediately id be checking the wiring, shortly id be looking for vacuum leaks (usually it's the oil vapor separator under the intake

Thanks Im going to go over it myself first. Can I check basic voltages and/or resistances with a VOM? Im an electronics tech so I know how to look at such things.

Know anything about Carsoft? How good it is? Cost?

Thanks for your input!
Tony

[winfred]

it's going to have a 12 volt feed going to the heaters in the sensors, the sensors make about 1v dc when they are hit with a propane torch and up to temp (usually about 30 seconds or so), if you have a graphing meter you can look at the responce time which is the most importaint part, at operating temp it should react quick to flame on and off of the tip, nearly straight up and down on the graph or about 1/10 of a second to fall to nearly zero