Hey Guys.....I don't know WHY it's true, but it seems that with respect to me and my Dakotas, small problems are usually impossible to track down and fix. And so I come to you Gentlemen on The Forum asking for your help help and guidance. But first I really do need to tell you that I come here as a last resort in the hope that my problems will not be seen as "bugging" you when I should have gone elsewhere first. I HAVE gone elsewhere - TWICE - and now at last it seems that my "professional" mechanic has resorted to the expensive and inefficient system of "throwing parts" at the truck until the problem goes away.... The original problem was (and still is) that I got a check engine warning light on my dash - intermittent at first and then finally becoming constant. In an effort to resolve the problem inexpensively I first visited my friendly Advance Auto Parts store. They plugged their little "tester" into my wiring harness and reported back that I had an emissions control system problem. I don't remember the name or number of the fault code exactly, and I have since lost the scrap of paper that the number was written on.... but I do remember thinking what an almost impossible job it would be to track down a leak in THAT SYSTEM (evap control system). So I decided to take it to a garage that I had done business with in the past and had some measure of confidence in. They also plugged their little machine into my wiring harness and reported basically that their findings were the same as Advance's. Then I asked them to list the top 4 or 5 possible causes of failure AND the price of fixing each cause. They said that before they would venture to make an intelligent guess as to the cause that they would have to run a "smoke test" on the system. I knew NOTHING about any "smoke test" but was pleased to hear that their method of fixing the problem would START with an intelligent diagnostic - hopefully foolproof - proactive test. The cost of that was $53.43 and I was happy to give it,, believing it to be a foolproof way of finding leaks. The "Top 4" causes of the trouble code were said to be (1) purge valve $122.79, (2) gas cap $22.36, (3) evap ++++ leak $18.20, (sorry - can't read the scribbling, and (4) Evap vapor cannister $335.34.... I then set up a time for them to run a smoke test.... waiting for the result(s) of that before deciding to spend any money on the more expensive causes of the trouble code. ..... So they ran the smoke test and then reported that they had discovered the cause of the trouble code and that it was NOT any one of the four most common that they thought it might have been. ....... It didn't take long before the ..mechanic and the service manager were standing in front of me holding some sort of electromechanical "gizmo" the likes of which I had never seen before. It was "L shaped" when viewed from the side and had a connector port with 3 "pins" intended for a 3-wire connector. It also had 2 "nipples" that appeared to be about 1/2" diameter AND a disc-shaped compartment - about 2 1/2" diameter - which was said to contain a diaphragm. But the most unusual thing about it was the way in which the mechanic said he was able to diagnose it. He said that "the system" was designed to operate under very low pressure - and that the best way to diagnose the part was to blow into it. He said that IF the part sounded like a duck when you blew into it it was OK..... but if not then the part was bad. So based on this "sounds like a duck" system of diagnosing I went along with the "fix" and had them replace the part (I'll call it a solenoid for want of a better name)..... So 3 or 4 blissful days passed (no trouble light), and then about the fifth day - guess what? You got it.... I started getting a check engine light again. Having just spent almost $200 to get rid of that pesky little light I immediately called the shop back and reported that and told them that I really DO want to get rid of this check engine light. They were courteous and we set up yet another time to (hopefully) further diagnose the problem and resolve it. So they ran another smoke test and this time told me that my gas cap had gone bad. SOooo.... another trip to the shop ND another part replaced. Thankfully, this time they only charged me for the price of the gas cap - and no labor for installation. So I leave the shop, go a few miles down the road, and guess what?! You got it - trouble light again. And by THIS TIME I'm seriously thinking that for some reason the causes for trouble codes on Dakotas are impossible to pinpoint.... OR this shop that I have always had a measure of faith in is not up to the task. ..... Now I've driven Mopars for years and most of them were JUNK because I was saving my money to get a really decent one. And now that I finally have a decent one (2004 SXT) I discover that it's apparently impossible to diagnose problems. Now I AM AWARE of the OBDI and the OBDII diagnostic systems - AND I have heard over the years some pretty astounding tales of just exactly how accurate and precise these systems can be. I've even heard tales of how the OBDII systems could spot a bad plug wire out of a batch of 8 wires. And I'm wondering why it is that these systems can be so precise on other peoples' cars but apparently cannot sort out a problem like the one I have on my truck??............ And like I said, I'm coming to The Forum as a last resort, for TWO reasons: I don't want to be seen as "bugging" you Guys, AND I figure there MUST BE a wealth of experience here that hopefully no one will mind me tapping. If ANY of you guys have ever seen ANYTHING like this I would be ever so appreciative for whatever advice and/or coaching you would be willing to give. "THANKS" in advance.... and May God Bless........ FredT

 

Need to know what the code is. Stop by advance, have it read again, and let us know.

 

Or do the key dance to get the code. Turn the key to run - not start, then off, back to run, off again, on again, off again and then leave it in run. Any codes should display in the odometer window.

It'll say "P DONE" when finished.

 

It's good to type in paragraphs. That big block of test made me stop reading after a while. Also year and engine you have helps.

Your code is likely p0442 or 0441 which means evap leak.

First thing to do is check all the lines leading to and from the evap system components (and everywhere in between). That means check the hoses going to charcoal canister, purge valve and leak detection pump. In my vehicle, they were also hoses running under the battery. Pull them off and squeeze the ends to see if there are any splits. If you find any, cut off an inch or so and reconnect.

I found split hoses and though fixing those greatly lessened the frequency of the check engine light, it didn't fully resolve the problem. My permanent resolution was replacement of the leak detection pump. The pump and solenoid are shared among many Chrysler vehicles. I just swapped my LDP with one from a 2009 PT Cruiser in the junkyard. You can use ebay to look up parts and view all vehicles that they fit if you're going that route. PT Cruiser and dodge ram from a wide range of years, if I recall correctly.

 

This is the leak detection pump, probably what the shop replaced.

As Dodgevity said, there is about 50 feet of hose in the EVAP system and they run all over the place. There's a hose from the intake manifold to the charcoal can (forward of fuel tank), a hose from the charcoal can to the LDP, a hose from the charcoal can to the fuel tank, and I forget where the rest are. There's 2 that run under the battery tray. when I removed my battery to put it in the bed, I found hoses that looked like spider webs in them from being so cracked.

 

Dak Dan - I didn't realize that this truck had the self-diagnose feature that Chrysler used for so many years. I believe - IF memory serves - that that was one of the FIRST things that I tried, and I believe that I found this truck didn't have that.


Dodgevity - yes, I realize that my story was lengthy, and I apologize for that but I felt it important to include all the details that I could while taking up as little space on the forum as I could. How's this? Any better??

Also, what you describe with respect to checking ALL the hoses was exactly what I had hoped to avoid... as I am somewhat crippled and find it extremely difficult to get down to the ground and back up again. I hope that YOU never have to endure that condition.

The leak detection pump pictured looks MUCH like the "gizmo" the mechanic pulled off the truck and showed to me. It MIGHT be helpful to you to know that he described that "gizmo" as operating at very low pressures (about 4 PSI), AND that he said that a good one made a noise like a duck when one blows into one of the "nipples"....(while a bad one makes no sound at all)..... (yeah, freaky I know)


Magnethead - thanks so much for the picture. As I recall, the part I was shown looks MUCH like the one you pictured - although probably not EXACTLY like it. I read carefully what you said about the hoses, and believe me - I can certainly relate to your comments. The ONE THING that I hoped to avoid by having all the computer checks run was to avoid crawling all over the truck and checking each inch of every line. Seems that that MIGHT BE unavoidable.


To All Responders: THANKS so much for your replies and ALL of your comments. You may be certain that I have read ALL, discounted NONE, and will be checking further as the weather and health conditions allow. The very FIRST thing I intend to do is let the truck diagnose itself by using the On - OFF - ON - OFF - ON self-diagnosing feature (IF the truck will even do that)...... I would ask you ALL to keep thinking and keep replying with possible solutions as they occur to you. Again, thanks so much for your replies. I appreciate them all........... FredT

 

Sorry, I meant to include these details, but forgot: 2004 Dakota SXT....... V-6 Engine, 3.7 litre I believe..... Thanks again...... FredT

 

Just checked the "self-diagnosing" feature on my Dakota again. As I remembered, this truck does NOT have that feature. Bummer. No lights or text messages, just a series of bells - this one rings six times... FredT

 

Found the receipt from the shop where the part was replaced. You are correct. The part that was replaced was described as a "leak detection pump".......... FredT

 

Yes, splitting up the paragraphs works. So basically the LDP's job is to pull a vacuum on the evap system. If the system doesn't hold the vacuum for a specific time, it throws a leak code. So, if the LDP is replaced, then you probably have a hose leak somewhere. Unfortunately, if you can't do it, you'll have to farm it out. It's really not as bad as it sounds. If you're in the ATL area, I'll be happy to help you.