Hello All,

This is my first post here. I am hoping to find an answer to an ongoing problem that I have had for nearly a month now.

I started about a month ago in deciding to have the alternator and serpentine replace because there was a consistent bearing rattling in the alternator that was getting worse and I did not want to be left stranded. That was replaced at a shop.

After getting the van back it began to develop a high idle. I noticed it mainly when it was in gear. The van would want to jump forward.

I took the van back to the shop that put the alternator on assuming that something with the alternator was causing the problem. They looked it over and ran there scanners on the alternator and battery and found not problems.

I then began to develop a problem with the speedometer jumping from 0-30 sometimes even up to 70 while idling.

With a friend I decided to try running Sea Foam through the vacuum. We had a lot of smoke like it was supposed to and got rid of the carbon build up but the problems remained.

A short time later I had a leak in my radiator core which was under warranty at a different shop. I took the van there and he replaced the radiator. I asked him to also look into the jumping and speedometer problem. He told me that the speedometer was likely going bad given the needle jumps and that the idle and jumping issue may be caused by the throttle body sticking. He gave me instructions and I proceeded to clean out the throttle body myself with throttle body cleaner and an old tooth brush. The problem remained.

I went a long trip and during I noticed that my gas gauge was not going up quickly after refilling. I would have to drive a few miles until the meter would rise and show the amount of gas that I had put in. But it did (and does still) work...just rises slowly after a refill. During that trip the speedometer also spun all the way around to the opposite side of the 'stop' at '0'. It stayed that way for several days but then spun back and began working again.

Shorty after returning from the trip the van developed a shifting issue. It would get stuck in second gear. I learned that it was the vans 'limp mode.' I got it in to the shop who repaired the radiator. He read the codes and told me that it looked to be something with the transmission (If I remember correct the codes were for the gear ratio and the speed sensor...not 100% sure though). He recommended a transmission shop for me to take the van to.

I took the van to the transmission shop that was recommended just last week. They diagnosed it and said that the culprit for all of the problems was the transmission control module. The showed me the TCM and it was very corroded. They said that likely water got inside. They also suggested to replace both speed sensors because there was metal build up on both. So new TCM and both new speed sensors. I got the van back on Monday.

Yesterday, only two days later I started to have the jumping/high idle again and the speedometer going all over. In the two days I had it I also noted a light screeching sound occasionally when it shifted from first to second.

I am at a total loss for what could be wrong. Right now it is back at the transmission shop but I am not confident that they will actually fix the issue. Lately this has been a non-stop money-sucking van.

If anyone has had similar issues that they have remedied I would greatly appreciate your insight!

 

Miscellaneous thoughts:

I would seriously consider heading to a different shop and have them install an OEM alternator. I have read of similar problems after alternator changes fixed by changing the alternator again regardless of tests results. I have no explanation as to why.

It would sure be a shame if this turned out to be a cracked, broken or disconnected vacuum line. A vacuum leak is a common cause for high idle. There are EGR vacuum lines in the vicinity of the alternator. A disconnected engine coolant sensor will do the same. It's also near the alternator. Make sure it's wire harness is not damaged.

Metal debris on the speed sensors is not good at all. It indicates something is wearing internal to the transmission. First thing I would do is drop the fluid pan and inspect for more debris. If it's there it's time for a transmission rebuild/replacement.

A jumping speedo with a simultaneous shifting problem can indicate a bad output speed sensor. The speedo and transmission simultaneously use the sensor as a data source. You can perform an instrument cluster self test to prove if the speedo is good or not.

 

I am also having the same problem, my van went in for a suspension reconstruction supposedly needed a new alternator, even though the alternator was changed last year. It came out of mechanics acting up. Took it to dealer with some codes popping up. Dealer fixed transm. Control module work bout 2 mos., then back again. Just fixed transm. Speed sensor, n still have same issue. I'm at a lost.

 

I am experiencing the same issues with the high idle, jumping, and surging gauge. I had the transmission changed, battery, plugs and harness, darn near everything but still have same problem. Is this happening with all caravans from that time or what? I would hope Dodge would look into this issue and provide a resolution. I could really use a fix for this thing.

 

Model year? High idle all the time? Jumping all the time? Which gauge? Getting any codes? Need details.

 

I ended up taking it to an electrical shop. They diagnosed and fixed the problem for under $200. Would have been nice to have know to do that in the first place before replacing the tcm and sensors which was much more expensive.

 

Can we get the details of the repair?

 

Does anyone knows if a 2003 caravan (3.3L) transmission would fit onto a 2002 grand caravan 3.3L ? both automatic and 3.3L

Thank you.

 

I just picked up a 2003, with a 3.3 and thought it was great the first few days, then I started having issues with the speedometer jumping when I stopped at a light and it would switch gears while stopped and go into the limp mode I brought it in and had the speed sensors changed and it still happens.
If this is electrical what should I look for.

 

Gosh guys, my gut says take it to a MOPAR dealership ASAP. With complicated hard to diagnose issues like this they should be the folks to look at her.

I have learned these Vans can be complicated to diagnose when acting up like this and the dealership perhaps has seen it all before and nail it on trip one.

I used to shy away from them but have found them to be very competitive these days. Have you priced an oil change at one lately? No shop in town here can go as low.

I have also found that once they get to know you they take pretty good care of you price wise. Going in for regular oil changes starts a great relationship.

G-Luck.