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Discussion Starter #1
Hey guys, if this gets a little long winded I apologize now. Here's the deal, replaced my 4.6 Romeo block with a remanufactured Windsor block, believed to be out of an explorer don't know the year, npi heads and reused the stock intake, egr, etc., well now it keeps throwing a P1406 code ( differential pressure feedback downstream hose off or plugged ). I have verified that the hose and mounting tube are clear of obstruction, by 1) attaching a vacuum pump and 2) attaching a vacuum coupling and another piece of hose and did the old suck/blow bit and had flow both ways. I'm thinking that the dpf sensor ( otherwise known as the egr position sensor ), is bad. My reasoning: the egr valve or solenoid can't be bad or I would be getting codes for flow malfunction, insufficient flow or egr regulator circuit ( solenoid ). Also the orifice in the tube assembly can't be obstructed or I'd be pulling codes for no flow or orifice restricted. The car passed the NJ smog nazi emissions test while throwing this code. and tripped the mil while they were doing the dyno test. Is there a difference in the location of the orifice tube assembly in the windsor as opposed the the romeo and are my suspicions on track, you guys probably have a whole lot more experience with these things than I do. Thanks, any input greatly appreciated.
 

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I read through the pinpoint tests in the service manual for that code. After verifying the hoses are not plugged and that they are connected correctly, the next step for the P1406 code is to go after the DPFE sensor (essentially, 'service' or replace it, as indicated in the manual).
 

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Discussion Starter #3
Thanks for the input IronChopz, like I said that was pretty much what I had deduced, but troubleshooting these newer engines really isn't my strong point, give me a chevy small block and that's simple. I also went back and double checked the egr valve with the vacuum tester and sure enough as soon as I applied a vacuum, the idle dropped. so I'll be picking up the sensor tommorrow. The Chilton's don't give the pinpoint test procedures. Thanks again.
 
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