Greg Bailey wrote:
> Hi, I've got a 1993 Dodge Grand Caravan, 170k miles, still in great shape
> bodywise and mechanically, still some life left in the old girl.
>
> Couple of months ago, I noticed the gas mileage going south, then the "Check
> Engine" light came on. Had it checked out, the EGR valve and coolant
> temperature sensor needed replacing.
>
> Since then it's run fine, gas mileage has been much better even around town,
> engine has seemed like it had a bit more get up and go.
>
> Yesterday morning was the first real cold morning we've had since getting
> the car worked on (am in the Deep South). When I cranked the van up to take
> the kids to school, the "Check Engine" light came on. I turned the engine on
> and off and it cleared that out and I didn't see it again the rest of the
> day. Did a lot of running around in the van and it ran fine.
>
> This morning, it was even colder. Cranked the van up and let it warm up,
> everything was fine, no "Check Engine" light. Did some more running around
> town, turned the van on and off several times. After my next-to-last stop,
> however, when I got back in and cranked her up, the "Check Engine" light
> came on and stayed on, and now will not go off.
>
> My main mechanic was not available today so I took it to another mechanic
> who I knew had a SnapOn machine and the only code it was throwing was
> "alternator circuit open or shorted."
First off it doesn't matter what machine you use.
the problem is that your alternator is PCM controlled so the alternator
can be in great shape and the car still won't charge. The light on your
dash is a good indicator.
As you can see by the responses you got, great mechanics have a problem
with these type of situations.

Find a good shop that ONLY works on Alternators and Starters and have
them bypass the pcm with a regulator. this will work just fine and save
you the cost of buying a computer for your car.
>
> The alternator is working and charging absolutely perfectly and the mechanic
> did a quick check for shorts on it, on the battery and on all the fuses
> inside. Everything checks out fine.
>
> He said this is likely in the computer and that I'd have to take it to a
> dealership to have them look at it. I'd really prefer not to, both from the
> cost standpoint and the fact that they're probably not going to be overly
> thrilled about me rolling in this 14-year-old van with 170K miles on it,
> they'd probably prefer I buy a new one which is not going to happen at the
> moment.
I work at a shop that only does electrical work on cars and trucks.
This is a very common problem we see.
>
> The mechanic said the computer might need to be replaced and pointed to some
> stuff down around the battery area ... sorry to be so indefinite, with my
> meager knowledge of all the parts of the car, I'm not quite sure what he was
> talking about ... said check with junkyards to try to find replacements.
Just get the pcm bypassed.
>
> He also said that as long as the alternator was charging as it was, we were
> in no real danger of being stranded anywhere and that the light would be
> only a nuisance.
>
> Can anyone give me any more specific ideas about what might be going on
> here, what I might need to have replaced to take care of this and maybe some
> reassurance that this is not a really dangerous situation, because having
> been stranded 90 miles from home one time when an alternator died, that
> concern is always in the back of my mind.

We at PASCO are your starting and charging specialists
410-546-2041
>
> Thanks in advance for any help.
>
>
>