Fixed LDP hose and still code 1494 - JeepForum.com
 
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post #1 of 5 Old 09-20-2017, 06:31 PM Thread Starter
Uniblurb
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Fixed LDP hose and still code 1494

Started my 04 4.7 tonight and CEL stayed on. Connected my scanner/reader to it and got the following code.

P1494 (M)
Leak Detection Pump Sw or Mechanical Fault
Incorrect input state detected for the Leak Detection Pump (LDP) pressure switch.

Then when I got out with it running heard a loud vacuum leak/hiss behind the driver's side rear tire.

I knew exactly what happened and sure enough some dam bushy-tail rat got up in there and chewed the hose to pieces connected to the leak detection pump top/tank side.

Since the hose was chewed in 3 places clear back in there I removed the rear wheel well cover. Luckily I had a piece of 1/4" ID fuel injector hose I could bend w/o crimping it since that OE hose is preformed 'U' shaped. I did find the wire to the the LDP pulled away from the frame but no chewed places on it.

After replacing the hose I heard no other vacuum leaks in that area. I tried to erase the code with my code reader and it said "command sent" but the CEL never went off. Still able to pull that same 1494 code back up.

Not sure if my code reader failed to remove the code or not? Or maybe I still have a problem back there with the LDP? Wouldn't think I'd have to remove the neg battery cable to erase the code and maybe it will disappear when driving it? Thanks ahead of time for any input!


96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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post #2 of 5 Old 09-21-2017, 03:16 PM Thread Starter
Uniblurb
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Bump, any input please if the LDP code will go away on it's own?

Thought the hose I replaced would fix it and would rather not tear into the whole LDP hose/wire system if there's no problem.

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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post #3 of 5 Old 09-22-2017, 04:02 PM Thread Starter
Uniblurb
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Found out in reading the 04 FSM the LDP code 1494 will go away on it's own if you want to wait for 40 key strokes along with perfect self-testing every stroke. No thanks.

It's no wonder my Actron scanner/code reader won't remove that code since it takes a DRB III tool to remove it. But disconnecting the battery does the same thing and code is now gone after removing neg cable for about 10 minutes. Yea, and the replacement LDP hose must have fixed it!

One thing I never could find an answer for in extensive searching. Why does my 04 4.7 Federal emissions WJ have a leak detection pump to begin with? I thought those were only for Cali emissions?

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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post #4 of 5 Old 09-24-2017, 09:38 AM
gtg413i
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Maybe it originally shipped to a Cali dealership and then got shuffled around? Glad you fixed it. Chrysler used cery cheap plastic on these hoses. The cruise control one will leak as well. Just replace them with gasoline hose. It's expensive but better quality.

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post #5 of 5 Old 09-24-2017, 11:47 PM Thread Starter
Uniblurb
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Thanks for the input. Actually that chewed up vacuum hose on the LDP seemed like it was in good shape with thick-walled rubber. But know the plastic hoses you're talking about and agree fuel line works well.

I had noticed I have an emissions sticker under my 04 4.7 hood edge which shows the LDP included. And my build sheet shows the following:

"NAS 50 State Emissions"
"NBGP Federal Tier 2, Bin 9A Emissions"

In doing a google search on the above I clicked on a jeepforum thread which just happens to be mod Chris Hager's build thread. Lol, and he has the same emissions on his 04 4.0 and lives in Illinois. Something tells me they started including the LDP on the Fed emissions on the late or last WJ's.

96 4.0 ZJ Laredo, 2004 4.7L WJ Limited, 96 4.0 XJ (son's)


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