1999 grand voyager failing emissions test

1999 3.3L runs great, but needing emission test, failed due to 'obd failure' drove it for 2 weeks on and off (75-100 miles), took back to shop and failed a second time with same error. Spent 200.00 for dealer to look at it and they indicated my PCM did have some old error codes in it, but that the PCM was failing its self-test. 500.00 for their new PCM, 400.00 for the labor to put it in ! I called my nearest salvage yard, they have a 99 3.3L PCM for 100.00 but no returns on electrical items. I did see and will return this to the dealer for the clockspring recall as my van did show the symptoms of this recall (I see this as a separate issue though). the battery was replaced over 7 months ago in the van and I drove it at least 500-600 miles since the battery was replaced so I do not think that is it. in GA. you HAVE to have emissions to get your tags so I'm in a jam and any help would be appreciated. (I read thru dozens of posts and see bus issues, dash issues with solder points) I don't know if a BCM and a PCM or ECM or one in the same nor where they are located, just that the dealer said my PCM was bad.

UPDATE 3-14-08 (took the advice of a forum poster and went to autozone (also today a friend from work lent me his code reader), NO indicator lights are on the dash at all (none staying on), used the friends reader, found one code (p0403), unit ran 16 various tests, the two egr related ones said failed to read.
then went to autozone, he put a tester on it and he said it found a p0403 code, he printed off the hardcopy and it says 'the pcm has determined that a malfunction exists in the control circuit for the exhaust gas recirculation system'
(on the print off from autozone):
definition: EGR system fault (exhaust gas recirculation)
explanation: the ECM has detected a fault in the EGR solenoid circuit
probable causes:
1) failed egr vacume solenoid
2) open or short circuit condition on the egr solenoid circuit
3) egr solenoid faulty
4) failed egr pressure sensor where applicable

they had the egr valve for 57.00 (no returns) but NOT the solenoid.
5) failed egr position sensor where applicable

*(this car did fail the test, but it failed since their emission tester could not get certain readings back from the PCM - per the emission guy, he said that
USUALLY meant that the car was going thru 'readiness' test of its own, and thus he had me drive it 50-75 miles.
so it did NOT straight up fail due to its emissions output but rather that they could not read the info from the PCM)*

I'm about ready to head back to the dealer to ask why their high-tech equip. did not tell me that (where my friends code reader did and autozones),
and why they would not recommend replacing a 50.00-something part(s) rather than their 'your PCM is bad, it will cost 900.00)

So would like IF the egr is bad (both parts or one of them), would that give an emission tester the 'obd failure' as the emission shop has seen and thus
failed the car ?
and COULD a PCM be bad by failing its 'self test' as the dealer told me (for 200.00) but yet the car, starts, runs great with NO issues at all ?

Thanks in advance on any directions...

Go to autozone and get the codes read and post them and someone will help.

Sounds more like it was rejected. Was the mil (check eng light ) on. What was the code?

I updated my post with additional info...I just added to my original post. -- thx-- jesse

P0403 = EGR control circuit. This means it is an electrical problem with the solenoid circuit. Bad solenoind; connector;or related wiring. Last cause is PCM. The solenoid is supplied power when the keyis in the run position. To activate the solenoid the computer grounds the circuit. If you replace it don't erase the code. If you erase the code you will have to perform the drive cycle so the monitors can be completed..

OK, I will check the solenoid connections out and get back to the thread -- thx -- jesse

UPDATE 3-17-08 I guilted the car dealership into performing the 'clockspring' recall (they did not want to do it)
I had them check EGR valve and solenoid connections (they indicated they looked ok), they told me AGAIN, that
my PCM is bad that it is failing the egr portion of the readings, I then asked what would happen if I replaced the egr
valve and solenoid, they indicated that IF either was bad it would put an error code out, but since the computer was
'jacked up' its possible that it would not.

I need some guidance...do I replace the EGR eqp. out first, or just go to my nearest salvage yard and get a 3.3L v6 gas,
PCM for 100.00 ?

I did find it curious that when I used my friends code reader, out of 16 tests, only 13 were working and getting readings, the 3
that did not get readings saying 'not ready' were EGR related ???

There are fault codes for PCM failure. At this time you only have a code for an EGR control circuit. It sounds like your friend has more than a basic code reader. Can you perform actuation tests with it? If so one thing you can try is set it to activate the solenoid and wiggle the wiring from the solenoild back to the PCM an see if you get any interruption in the activation while doing this. The solenod when it click is not very loud so you have to listen really good. Also ck the harness around the battery area; acid can cause problems there. If you do opt out to the pcm from the junk yard you have to be careful. Does your van have factory theft alarm or does the van you are getting it from have it not a good scenario. Pcm and BCm swapping can cause you more trouble.