I have a 2011 Grand Caravan Crew with approx 75K miles.

A few weeks ago I had left home and the battery light came on several minutes from home . Mechanic checked all the various voltage readings and said that battery output was good. The alternator was fairly new (still under warranty). However, the diagnostic code that came up caused him to suspect the diodes might be going bad, and so he went ahead and replaced the alternator (Didn't cost me anything as it was still under warranty). Battery light came on again.

Whenever the light comes on, I can shut off the motor, and when I restart it, the light does not come on. However, as I drive for a few minutes, the light sometimes comes back on.

The mechanic replaced the new alternator with an an OEM alternator and he replaced the connectors on the wires that plug in to the alternator. Last week we drove on a trip about three hundred miles from home. Drove around for a couple days sight-seeing and no battery light. We drive towards home and get about three hours from home and the light comes on. We stop for lunch and when I restart the van the light doesn't come on and we drove the last 150 miles and no light came on.

I've driven it a few times since and the light came some of those times (not every time) after a few minutes of driving. When the light is on, the battery isn't charging. When the light is off, the battery charges normally.

My mechanic replaced the OEM alternator with another new OEM alternator (4th alternator in a month-we can safely say the problem isn't the alternator), slid in a new battery (also under warranty), and redid the plug connectors, and checked the wires for kinks and shorts. Still getting the battery light.

To my mechanic's credit, he has not charged me for ANY of these parts or labor because they are under warranty. He is now suspecting a computer issue since most of this voltage runs through the computer.

Any one have any ideas? Wiring problem? Grounding problem? Funky battery problem? What do you think? What else could it be? The mechanic is talking to one of the service guys at the local Dodge dealership for other ideas.

 

Often times those (crappy) OEM alternators shorting will take out the field coil circuit in the PCM. You have about 5K miles left to get that covered under your 8/80.


I end up doing about every 1 out of 7 after alternator failures.

 

Mechanic ran the diagnostic code and it kicked out a P2503 code - low voltage code. Since he has already changed the alternator four times and replaced the battery and replaced the connection wires to the alternator, he will look at the PCM. He verified our warranty with the local Chrysler garage if we needed a replacement module.

 

UPDATE: My mechanic had the local Chrysler/Dodge folks look everything over. Diagnostic code read P2503 (something about low voltage). They checked the PCM and said it was working fine. They checked all the wires to and from the alternator and said they were fine, ran tests all through the electrical system. Claimed that they traced the issue to the alternator - not producing enough charge to run the various electrical items (radio, wipers, air-conditioning and heating fans, etc.). Informed us that there is a national backorder for that particular part for my vehicle.

The van has had four new alternators over the last month. Why would it need another one?

 

Pshht. I wish I could help. I'm still calling PCM. The Field Coil ckt test will almost always condemn the alternator if a tech follows the flow chart with procedural blinders on.

 

I realize that this post is a few years old now, but I am having a "similar" issue with my 2011 Grand Caravan and would really appreciate any help I can get. I don't have any warranty remaining at this point and am in no position financially to be forking over hundreds of dollars - or more - into this POS.

Last Monday (July 12th, 2021) I was driving home with the family from a city about 2 hours away from our residence. As we were coming up to the closes neighboring city, the battery light came on, so I exited the highway and found a place to park so that I could check things out with my scan tool and multimeter. After seeing that the battery was very close to full capacity still at this point, and finding no DTCs to indicate any problems, paired with the disappearance of the battery light after starting the van up again, I decided to get back onto the highway and head home to figure things out there. Well it was a very close call, the light came back on moments after re-entering the highway and the result was nearly losing all power completely and only barely managing to limp it into town to park it in my driveway. Since charging the battery, I've experienced this same issue with the light not coming on until after I've driven a ways, sometimes only a minute or two, sometimes longer. Since yesterday however, the light has remained on and the charging system is not functioning properly at all. I have read some overviews and watched some explanations of the charging system - though I still don't understand it - and I'm not sure if the PCM or the alternator should be the focus of my efforts to repair this thing. I've read more than one horror story such as this one where individuals have replaced the alternator sever times without successfully resolving the issue, but I've seen equally as many where individuals have replaced the PCM, just for it to turn out to be the alternator. Is there a fool-proof way to determine which is the actual problem? I can afford to maybe buy the parts and do the replacement myself, but I definitely cannot afford the $700 service quote I got from the local mechanic to test the electrical system and replace the alternator (should that be the culprit). This couldn't have come at a worse time, as my daughter has two birthday parties she's been looking forward to attending this weekend, and I feel like I've let her down by not having this figured out by now so that she can make it there. I thought it would be a "quick fix" of simply replacing the alternator - though I'm not thrilled about the expense - however I'm not so sure that's the case after everything I've been reading. I have taken some multimeter readings that I can share, but none of it tells me anything because I don't know enough about the charging system to really make any sense of what I should be seeing vs what I am seeing. Sorry for the novel, and thanks in advance for any help anyone can give.

Multimeter Readings:

note - alternator harness wires were probed at the harness every time, used the same chassis ground as reference every time except when testing the PCM fuse - in which case I used the battery negative post.

1) ​​​​​​Vehicle off, battery just taken off charger and put back into vehicle
- Alternator Sense wire (Red/Violet) at alternator harness ~ 12.6v
- Alternator Field wire (Brown/Grey) at alternator harness ~ 0V
- PCM fuse (M28) ~ 12.6v

2) Vehicle Running 1st time after installing charged battery

- Red/Violet wire ~ 0.3V- Brown/Grey wire ~ 11.5v

3) Vehicle off after first run
- Red/Violet wire ~ 0.0v
- Brown/Grey wire ~ 11.5v

4) Vehicle Running a second time

- Red/Violet wire ~ 0.0v
- Brown/Grey ~ 12v

 

Just wondering if you came with in ideas and conclusions with the results of how the vehicle got fixed