DTC P1494 (switch fault on Leak Detection Pump in EVAP emissions system) has been set on my 2001 Dodge Ram Van 3500 5.2L for a couple years now. Knowing it doesn't affect drivability/performance much, I haven't bothered to look into it a whole lot until now.

I pulled the Leak Detection Pump and have inspected all vacuum lines. Vacuum lines all look pretty good (I replaced a cracked line at the canister but I still get the code) and I have replaced the gas cap. With 12V power supplied to the LDP, I can hear the solenoid activate. Resistance between LDP sensor signal and PCM is 3 ohms.

On the LDP, I found a vapor line attachment that appears to be broken off. Attached is a photo of a new LDP with the missing attachment circled. I didn't take a picture of mine but can later if it would help.

However, I cannot find where a vapor line from that broken attachment should plug into. From diagrams it looks like it should plug into the T connector that connects the intake manifold to the purge solenoid. However, the port on that T connector is already occupied by a line that goes to a baseball sized plastic sealed ball where it dead ends. See pictures. I cannot find any info on what this baseball sized plastic part is. Does anyone have any knowledge of this? From most diagrams, it looks like instead of this plastic ball, the line from the T connector should plug into my LDP where the broken attachment is.

I am wondering if someone broke that attachment on the LDP and then instead of getting a new LDP, plugged the hose into this mystery part. But that seems like a strange solution instead of just plugging the line. This mystery part also has a strange mounting configuration, where it has a metal bracket that just grabs the bundle of wires coming from the fuse box. Seems weird, but the part doesn't look like it was some garage fix, it looks more like an OEM part.

Any help or other ideas would be awesome!

New LDP with attachment circled. My LDP is missing this attachment and it appears to have been broken off. Inside the LDP from the break looks like a very very small opening (maybe not even an opening), hard to tell if it would even allow vapor to pass through.

T connector in question. Left arrow goes to intake manifold, down arrow goes to the unknown plastic baseball shaped part, right arrows go to the purge solenoid.

The mystery baseball shaped part. I don't see it in any manuals/diagrams I have found. The vapor line from the T connector dead ends here. In all diagrams I have seen, the line coming from the T connector goes into the LDP attachment instead of going to this mystery part.

 

The baseball feller is a vacuum reservoir.

 

Thanks! Good to know.
Any idea where a vacuum line coming from the LDP would plug into? Or if the LDP for my year/model even has that smaller vacuum line? It is hard to tell from the broken bit if it was actually a nipple for a line or not, but the images of new LDPs online all show that smaller nipple present.
My LDP has two larger lines, one to canister and one to filter. I don't see any other open connections going to either the purge solenoid or the intake manifold (where I would expect a vacuum line connecting the LDP).

 

That, I don't know. Don't drive anything that new. There *should* be a label on the radiator support though, that shows vacuum line routing. If it doesn't, or isn't there, should pick up a service manual for your van. You can get an electronic version pretty cheap these days.

 

Thanks, there is a vacuum diagram on the underside of the hood, but it is very basic and doesn't have the detail I need. Same thing with my printed Haynes manual, it has vacuum diagrams but they aren't detailed/vehicle-specific enough to show the lines in question.

Do you have recommendations for a brand of manual (online or printed) that is good? I have been happy with the Haynes manual for other jobs, but it is a little lacking in some diagrams (vacuum hoses, wiring diagrams, electrical connector pinouts, etc.).

Thanks!

 

The actual factory service manual. I believe they are published by Bishko.

has 'em in hard copy. They *should* be available in pdf format somewhere as well, but, that search turns up some really weird stuff, that isn't even remotely related.