P1405 service engine code.

[rv4fun]

'97 Aerostar, 3.0L automatic (only 285k miles) - P1405 Service Engine Code coming on every now and then. Here's what I found with a web search:

DPF (Differential Pressure Feedback) EGR Sensor upstream hose off or plugged conditions. Engine running, then the PCM detected a sensor signal that indicated EGR flow in a negative direction with EGR valve commanded closed.

So, can anyone translate for me? Is there a hose on the EGR valve I should check or should I just start by replacing the EGR valve? What does the DPF look like and where is it located? :scratch:

Thanks for any help!

 

[BrooklynBay]

You're looking for a small part which resembles the old MAP sensors. Take a look at the top middle rear of the engine for the DPFS. Water or oil could get into it & ruin it. Since it has an intermittent trouble code, take a look for a cracked vacuum line going into it. Follow the vacuum routing diagram under the hood.

 

[rv4fun]

I found it - but ~ I can't get at it. I can just barely see it from the front or though the access panel under the dash. I see two short rubber hoses that transition to metal tubes. One goes to the exhaust pipe but I haven't been able to see where the other one goes. I think it's supposed to end up at vacuum port on the manifold.

I tried to take the throttle linkage loose to so I could get past it but the screws seem to be frozen in place. I didn't want to twist off the heads so I sprayed them with some PB-Blaster and came inside.

The temp was almost 70 when I started the job, it fell 10 degrees while I was working on it and since the sun went down, it's dropped another 20 degrees and it's not going to warm up any time soon so it will be awhile before get back to it.

While I was trying to get at the hoses, I shoved the camera in and around to take pictures from angles I couldn't see. The image below shows a hole in the hose that's probably causing my code.

Here, the original DPFE is metal - the picture at the top of this post shows a replacement.

If only I could get a hand back in there - the hose is less than a foot long and would be very easy to change if I could only get at it. The hose on the right in the picture is the "REF" hose so the one with a hole in it must be the "HI" hose.

 

[Jose A.]

'97 Aerostar, 3.0L automatic (only 285k miles) - P1405 Service Engine Code coming on every now and then. Here's what I found with a web search: DPF (Differential Pressure Feedback) EGR Sensor upstream hose off or plugged conditions. Engine running, then the PCM detected a sensor signal that indicated EGR flow in a negative direction with EGR valve commanded closed. So, can anyone translate for me? Is there a hose on the EGR valve I should check or should I just start by replacing the EGR valve? What does the DPF look like and where is it located? :scratch:
Thanks for any help!

not sure about the 3.0 liter, but in the 4.0 liter there is a sensor (black box) with an electrical connector and two rubber hoses from the sensor connected to a tube below the EGR valve which itself is connected to the down pipe.

I would not replace the EGR Valve yet, instead remove the metal tube under the EGR Valve, (one large nut at the valve, one large nut at the down pipe), and clean the tube which could be clogged with carbon deposits. That is what the Service Manual for my '97 says to do first. If you don't clean the tube, and just install a new valve, the Code will come back.

you will need a drill with a long extended thin metal brush to insert it in the thin tube and clean the sludge as it rotates. You can buy the brass brushes at auto parts stores. Otherwise dip it in some solution with acid that will not eat through the metal, or take it to a Machine shop?

If cleaning does not clear the Code, then it might be the Sensor itself gone bad.

 

[Jose A.]

I found it - but ~ I can't get at it.

remove the pipe/tube to get at the hoses, you have to clean it anyway. A big heavy wrench will give you the leverage on that big nut. You don't need to remove the EGR Valve.

 

[BrooklynBay]

Moisture ruins the DPFE sensor. Remove the inner dog house cover to get to this part.

 

[rv4fun]

I still couldn't reach it from the inside with the access cover removed. If I take the passenger seat out, I might be able to get a better angle on it from inside. If I could take the plate that holds the throttle linkage, I'd have a good chance of getting at it but the two 10mm head screws that hold it in place are frozen right now. Maybe I can get some heat on them along with a good dose of PB Blaster to coax them out. I'd hate to twist them off and end up with more work than I've got already.