Well I need some help and guidance. This is a early 2003 6.0L Excursion.
Have had the P006A come up with P0401, removed the EGR cleaned the dry build up, put a new Ford one in. Cleared the codes. Still getting the P006A will not pass the CA Smog check because of this. If I clear it and take it in to check the smog test says that the system is not ready. what should I look at/for in what order? Thank you in advance.

 

Once cel codes are cleared the vehicle will have to be driven enough miles for the OBD2 sensor readings to accumulate enough data for the ECM to consider everything is working OK. Usually 100 miles with multiple starts and stops does it. The smog guy is saying it wont pass because its too soon since you cleared the codes. Drive it for a week or so and bring it back to have him once you have determined and fixed the reason for the P006a code popping up. Some successfully cleared this by cleaning the MAF sensor while some found leaking CAC boots were the problem.

 

Do you have any means of monitoring sensors? The PCM monitors IAT1 & IAT2 while the EGR is activated to see a rise in temperature on the IAT2 sensor. If either sensor is not working correctly it can throw a code. If you have ScangaugeII or a scanner verify the readings cold after sitting overnight and then running @ idle.
IAT1 (Intake Air Temperature sensor #1) is in the mass airflow sensor. You can try cleaning it with Mass Airflow Sensor spray cleaner.
IAT2 (Intake Air Temperature sensor #2) is screwed into the intake near the oil filter housing. Pull it out. It more than likely will be clogged up. Clean it out carefully. It is a plastic cage surrounding the sensor so be careful. Or just replace.
The above is a good start.

 

Good point on the iat2 sensor as it likely is crudded up if the egr valve was full of stuff. I cleaned them successfully just spraying maf cleaner and using a soft paintbrush. Typically you get the low egr flow Code (P401 iirc) too when the temp corrolation isnt correct due to plugged egr cooler or cruded up iat2 sensor.

 

OK I will check the sensors and use MAF cleaner for the IAT 1 & 2. Will check all the CAC boots & Clamps. Thank you

 

Make sure you tell the operator that he needs to do a prelim check to ensure you've driven enough to have cleared the codes for testing.
They won't ask you and if it's not ready, usually charge you for another test.
After the prelim test, he'll send you on your way again for more driving to clear if not ready, providing you fixed the issue.
I've found it needs approx 150 miles, idle time, 5-6 restarts, street driving at 35 mph, and freeway driving for 15-25 miles.