How to clear the EGR error?

In Texas, for the annual state auto inspection, now they check the computer codes if they see the Engine Check bit set on the computer. Mine was set but I guess my light was reset or something because I
never saw it on since the time I bought the car used. Anyway, it was set because the computer says my EGR sensor is low and my EGR tubing is clogged. I replaced the EGR valve and the tube turned out to be very clean inside. The repair man said I had to drive through many different driving conditions and scenarios to be recorded before the error codes would clear. I have driven very much since but the codes are not clearing. Does the O2 sensor have to be replaced or something like that even though I didn't get an error for the O2 sensor? One of the conditions is that I have to drive when the outside air temperature is over 70F. Is there maybe an outside air sensor that could be out? What usually stops the EGR codes from clearing? Is it a problem with the computers software and is there a software update that fixes the computers' inability to ever clear the error? Thanks if you can help, George
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What is the model and year of this vehicle?
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Sorry I forgot, it is a 2000 Honda Passport which is the same as an Isuzu Rodeo but sold under the Honda name. reader wrote:

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You can clear all codes (including history ones) by disconnecting PCM power supply (or battery for that matter). AFAIK you still wouldn't pass emission tests as these guys require that self-tests that PCM does have been completed, and along with clearing error codes you're erasing self-test results as well. Now, I'm not entirely sure how long it takes for these tests to complete - you definitely have to do a bit of driving tho. Still, it must be less than clearing history codes - usually history is cleared after X ignition cycles with no errors, where X is at least 30 (depends on the initial error code).
Or is your mechanic referring to completion status of these self-tests?
Here are coupla links that can come in handy:
http://www.nyc.gov/html/tlc/downloads/pdf/readyness_failure_fact_sheet.pdf
http://www.txdps.state.tx.us/vi/publications/brochures/OBD_guide.pdf
Peter
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The mechanic cleared the codes after the work and said the same thing about having to complete the self test. He puled out a big book and started reading through the self tests that the car does. There have to be at least 15 times of the engine warming up from a cold state and being driving through different conditions like driving so much time around 30-35 mph, driving at highway speeds for so long, driving in cold weather, warm weather , with tank at least 3/4 full, and on and on.
I've been driving quite a bit but I'm not sure if it failed inspection again because the test didn't finish or it finished and failed the test again. I guess I need to go back and ask about this. I don't know if the mechanic can tell if it is finished. Maybe he can only see that the errors never went away.
Peter wrote:

the
codes
something
PCM power

emission
self-test
these
Still,
cleared
(depends on

self-tests?
http://www.nyc.gov/html/tlc/downloads/pdf/readyness_failure_fact_sheet.pdf
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Get yourself one of these:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&itemE24636537&categoryC989
Check first what kind of interface your car uses. Then download free software from scantool.net and you'll be able to see for yourself any history error codes, test completion status, and much more.
Peter
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In case anyone else ever has this similar problem, the EGR valve was good and the EGR tubing was clear. The clog was in the EGR tubing of the intake manifold after the EGR valve. After taking off the intake manifold and cleaning it out the problem codes were cleared.
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Do you know what caused the clog?

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