EGR Valve Sensor - Resistance Values

[aznriptide859]

Hey this is a bit of an urgent request:

I went to AutoZone the other day to check my engine light codes, and the guy pulled up a P0402, which means the EGR valve/EGR sensor has gone bad. I've checked the sensor - the end was pretty gunked up, and so far I've cleaned it. However I'm getting very big resistance readings - almost 200kOhms.


My question is, was that gunk causing my engine light to turn on, or has the entire sensor gone bad? If it did go bad, shouldn't I have no resistance reading at all?

My engine is open ATM, and I need it for work tomorrow, so if someone could help me ASAP, I'd be deeply thankful. Thanks!

[chronoti]

well the senor wuld be bad if it give a reading out of spec, i think 200k is right for cold i know hot (to where it closes) is about 47k. i just bypassed mine with a resistor and trashed the whole egr

[aznriptide859]

Did a quick test - heated up the end of the sensor, resistance dropped. That means the sensor is working.

Does that mean the gunk did have something to do with it?

[chronoti]

i'll go with yes, also try and clean out the rest of the egr, and vacuum modulator

[aznriptide859]

Grr, light came back on. Though sensor works, which really confuses me. Could it be the entire valve that has gone bad?

Also:

How do you use a vacuum to test if the EGR valve works or not?

How can you clean the EGR system tubes? Can you just spray carb/choke cleaner and let it sit?