I have an EVO8 with V390 where the cams are set to, I think -3/-2. The P0401 comes out every 100 miles. I have checked all the hose and they are all tight. No breaks on the hose. If this is a sensor problem, the service light should light up at an early mile run. Does the car's timing retard when the P0401 comes on? I don't feel any power loss. Des it have something to with the timing retard? Is there any flash that I can have just to make this code not to appear in the scanner? Really need help on this one. Thanks.

 

No problem....it is one of two (or both) small vaccume lines that have popped off the EGR valve located on the back of the intake manifold a bit tough to get to but the valve will feel like a hat with a brim...because of increased boost they need really to be zip tied....
hope you sort it out

 

thanks. I'll tighten all connections. at this point there are no clamps that hold it. somehow the dealer did not put any after they serviced the synchros.

 

????Clamps???...there should not be any clamps
..so the dealer disturbed vaccume lines on the intake manifold when they removed the tranny

 

OK so what should I use to tighten the connections of the vacuum hose? tie wraps. The dealer cut off all the vacuum hoses for the EGR system just to bring down the transmission and fix the synchros. I have no idea why. I have followed the EGR diagram under the hood and the only difference that I see is that according to the diagram, the solenoid valve that routes to the EGR valve and intake manifold has three connection; 1 directly from the intake manifold, the second one coming from the intake manifold uses a T connector that also connects from the EGR valve (hat with a brim), and the third one directly from the EGR valve. All these 3 connections go to a solenoid valve that is way underneath the instake manifold, right side of the alternator. This solenoid valve only has one vacuum connector but the diagram says there are three connections so when I looked at the hose, it uses a 3 to 1 connector to connect all the hoses coming from the EGR and intake manifold.
Is the EGR system connected properly? I never had any P0401 before until the dealer fixed my synchros. The cycle on how the P0401 is generated is interesting and this should be a challenge when troubleshooting it. It generates the first P0401 code after 30 miles. At this point it doesn't trigger the service engine light. The second time it captures the P0401 code is around 100 miles so there is a 70 mile difference. Doesn't make sense. All this observations happens after I disconnect the battery and run the car on the highway. I don't think I'm getting a boost leak comewhere but it definitely is a vacuum somewhere. Seems like todays OBD2s are very smart. I'm beginnig to suspect the vacuum loss generated by the CAM gear's timing retardation.

 

No...I am sure more attention needs to be taken at the back of the manifold....
double check all vaccume lines with a buddy's car...
Also check the gaskets integrity where the EGR valve meets the manifold as the dealer could have damaged the valve itself.....
Sorry to hear you are having so much trouble with this