Chrysler Repair: 02 Caravan 4 cyl.; check engine, dodge caravan, egr system

Question
QUESTION: Dear Roland,
We have a 2002 Dodge caravan 4cyl with 175,000 miles on it. It's been a good one!. Today the check engine light came on and it's idle is rough coming to a stop. Befor we get ripped off any idea what might be causing this? Much appreciated.          Andrea

ANSWER: Hi Andrea,
The engine light coming 'on' is helpful because it says that the engine computer has recognized a problem that is probably causing the roughness coming to a stop. The best approach is to go to an Autozone parts store if there is one near you where they will plug a code reader into a socket under the dash and tell you what the 4-digit fault code number is. If there isn't such near you, then an independent shop will do this for about $40. There is a chance that simply cycling the ignition key "on-off-on-off-on and leave on" doing that in 5 seconds or less will cause the code number to show up in the odometer window of the speedo unit, but if not, so be it. Then just get it with the plug-in reader.
Then write back with the number and also if the read-person tells you the name of the code, recommends what to do and for how much, tell me that too. We can compare what you learned against the shop manual directions and go from there.
Roland
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---------- FOLLOW-UP ----------

QUESTION: Hi Roland its the sick 2002 dodge caravan again. Actually it's not idling so rough today. Could the fact that I put premium grade gas in it have anything to do with the idle? Also my husband took it to Autozone and the guy there said the code is T0401, EGR system fault? He recommended we take it somewhere to be serviced, the part alone is 150.00!! eek

Answer
Hi Andrea,
The egr valve could well be the cause of on-again, off-again poor idling (assuming that there is one; check on the underside of the hood for the emission control system 'sticker' to be sure. It wasn't used in on the 4 cyl. according to my most recent, '98, van manual, but was used in the cars with that same engine in in that time frame. But there could indeed be on in your more recent van.) It would be something that your husband can deal with this problem at no cost.
The egr is located in a small pipe that runs from the side of the exhaust manifold back to the area of the air intake at the rear of the engine. The body of the valve is bolted into the pipe. To find it, look at the engine oil filler cap, and just below that you will see a round pillbox-like device with some vacuum hoses attached to it and a small electical valve on its top. Follow the vacuum hoses to find the nearby valve/pipe in question. Once you find the valve notice that it has a round top to which a vacuum hose is attached, and then a flanged area between that and the valve body in the pipe. Inside the flange opening you will see a rod which is the stem of the valve itself that moves back and forth by vacuum-actuation in one direction and spring-action in the other (closing) direction. That stem has to move freely or the valve will hang up ajar and not be closed when you come to a stop or even when you try to start the car. When that happens it will make for a rough idle/no start kind of behavior.
The fix is possibly simple. Take a spray can of WD-40 and with the straw-applicator squirt some of that on the metal rod where it enters the valve. Then notice that the rod has a slot and if you put the tip of a screwdriver in the slot you can move the rod back and forth as I described it is supposed to do. Move it/spray it alternatively to be sure the spring-action is closing it to a dead stop. That will usually solve an egr problem. But sometimes you have to take the valve out of the pipe and clean the inside passageway. But in most cases you don't have to replace the valve. So give this a try.
Roland
PS Use the 'thank/rate' tab below to get back with further questions. There ia a space for comments to which I will reply. While there, if you find this answer helpful, please feel free to nominate me as 'expert of the month'.