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. I have a 2010 srt8 my alternator died first had it changed twice and the battery. But alternator still won’t charge the battery car keeps dying. Dealer said buy a new ecm. I sent ecm to get fixed. They said there’s no problem with it we will update it. Put everything back in now A/C button flashes, no air blows, passenger airbag light is on and battery still not charging.
HELP!!!
 

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What’s the mileage on the car?

Do you know the car’s maintenance history? Has there been any electrical issues in its past?

When you start the car, by jumping it off or not, will the engine stay running until you turn it off?
 

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. I have a 2010 srt8 my alternator died first had it changed twice and the battery. But alternator still won’t charge the battery car keeps dying. Dealer said buy a new ecm. I sent ecm to get fixed. They said there’s no problem with it we will update it. Put everything back in now A/C button flashes, no air blows, passenger airbag light is on and battery still not charging.
HELP!!!
If the alternator doesn't charge the battery -- and which also means it is likely to not be able to supply the electrical power the engine/car needs -- that reads like a voltage regulator problem.

The battery is needed to supply electrical power to the alternator's rotor. The amount of power (around 2 amps) the battery supplies is used to control the amount of electricity the alternator generates. At idle the power the battery is required to supply is "high" so at idle the alternator is able to generate sufficient electrical power to supply the engine/car needs.

But if this much power from the battery to the alternator was constant as the engine speed goes up and the alternator spins faster the power output of the alternator would be too high. By reducing by how much the rotor is energized this reduces the power the alternator produces at high speed.

Won't detail how a voltage regulator works but with modern cars the engine controller plays a role in controller the voltage regulator to in turn control the output of the alternator.

That two alternators -- which I assume each had its own -- they are are part of the alternator assembly now -- voltage regulator -- both failed to keep the battery charged does point to either an engine controller problem or perhaps a wiring problem. The engine controller signal -- in whatever form that is -- is not making it to the voltage regulator and as a result the alternator is not supplied with enough power from the battery to generate enough electrical power to charge the battery while satisfying the needs of the rest of the car.

So the ECM repair company found the engine controller ok. But flashed it. Well, this introduces another possible problem. Flashed it with "what"?

I'd try to get the engine controller flashed with the correct version of firmware for your car. For this you probably need to take the car to the dealer.

Then someone needs to determine the engine controller signal or signals that control the voltage regulator are making it out of the engine controller to the voltage regulator and the signal (signals) look reasonable. I have no idea what the signals are. Could be the voltage regulator receives CAN signals (messages) which tell its controller the amount of battery voltage to allow to flow to the alternator rotor.

But the integrity of the the control signal from the engine controller to the voltage regulator -- and there may be a feedback signal from the voltage regulator to the engine controller -- the engine controller may monitor voltage output to come up with what it sends the voltage regulator -- needs to be confirmed.
 

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. I have a 2010 srt8 my alternator died first had it changed twice and the battery. But alternator still won’t charge the battery car keeps dying. Dealer said buy a new ecm. I sent ecm to get fixed. They said there’s no problem with it we will update it. Put everything back in now A/C button flashes, no air blows, passenger airbag light is on and battery still not charging.
HELP!!!
Hi Jonas.V, We're sorry to hear you're having a hard time with your alternator. If you're thinking you'd like to have this looked at by the dealer, let us know. We're available via direct message and can help with this process.
Rob
DodgeCares
 

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Discussion Starter #5
Hi Jonas.V, We're sorry to hear you're having a hard time with your alternator. If you're thinking you'd like to have this looked at by the dealer, let us know. We're available via direct message and can help with this process.
Rob
DodgeCares
Well i did get the alternator changed by pep boys twice. They did it the second time because the problem still existed they though maybe they got a bad alternator. After changing it again they looked around for other possible problems, they said they couldn't figure it out and advised me to take it to the dealership.
Took it to the dealership and was told they would need 3hrs of payment just to look at it, i told them the whole problem and events. They came back and said that the ECM was not talking to the alternator to charge the battery. They want 1,700$ for a new system and install.
So i sent out the ECM to get it looked at (computer car place) they told me they saw no problems with the ECM and was not able to reduplicate the issue.
Just got the ECM back from them and plugged everything back in with a new battery. (can't tell if the system is fine because now the air wont blow and they A/C , Defroster buttons flash. Plus the airbag fault warning light is on.
Car is collecting dust because i don't know what to do next, specially due to finances. Definitely hard to stretch my VA disability to cover extra things.
Once i save up more dollars i will get back into it so im looking for directions or ideas once that happens.
 

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Discussion Starter #6
What’s the mileage on the car?

Do you know the car’s maintenance history? Has there been any electrical issues in its past?

When you start the car, by jumping it off or not, will the engine stay running until you turn it off?
Ive had the car when it had 10k. i've had it for almost 3 years now and it's only had one problem before when it died and all it took was a bran new battery to fix it. (7 months ago)
So when the car dies i cant jump start it, for some reason it will only start once i take the battery out and charge it.
On the day the alternator died and this whole thing happen i did change out the front brakes and to make sure it was holding on i did a few hard stops, not sure if that means anything.
 

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Ive had the car when it had 10k. i've had it for almost 3 years now and it's only had one problem before when it died and all it took was a bran new battery to fix it. (7 months ago)
So when the car dies i cant jump start it, for some reason it will only start once i take the battery out and charge it.
On the day the alternator died and this whole thing happen i did change out the front brakes and to make sure it was holding on i did a few hard stops, not sure if that means anything.
Interesting...there is a lot going on here, and there are just too many variables to be able to effectively troubleshoot over the internet.

Nevertheless, in the interest of something is better than nothing, I’ll throw in some things that occurred to me which may or may not be of use to you in your search for the resolution to your problem:

- a single discharge event can permanently damage a car’s battery. You’ve had several it sounds like. You should remove it and fully charge it and take it somewhere to be tested. That’s really the only way to know for sure it is still good. You’ll need a fully charged battery to most of the diagnostic steps required to find the problem I’m afraid.

- the battery is there to start the car. If it does not have enough charge to do that, jumping it off should always be able to start the car since you are (temporarily) taking the battery out of the equation and utilizing the jumper car’s alternator to provide the electricity needed to turn the starter.

- as long as there is a battery present and correctly hooked up (to complete the electrical circuits in the car), it’s status as good/bad and charged/discharged is irrelevant when it comes to keeping the engine running. Once running, the alternator should keep it running all by itself until you turn off the ignition. If it does not, there is something wrong with the alternator or the wiring connecting it to the rest of the electrical system.

- the little red battery light on the EVIC can be deceptively useful in troubleshooting these types of issues. Once running, pay attention to its illumination (if it comes on, when it comes on, and for how long each time) and communicate that to anyone you task with troubleshooting the car’s electrical problems.

- a simple digital multimeter can be surprisingly useful for issues like this. If you have one, checking the alternator’s output is possible, which should help rule it out as the culprit here. The DMM can also be used to perform voltage drop tests on the main wiring connecting the alternator to the rear PDC in searches for bad connections that might be at play here.

- what about any DTCs stores in the computer’s memory. They may be present and useful in troubleshooting this, but you would need an ODBII scanner to retrieve them. Such devices can be purchased on the cheap from places like Walmart for as little as $20 IIRC. You can have local auto parts stores read them for you for free, but only if you can get the car to their store locations.

- a bad PCM is listed as a possible culprit in every problem that could possibly affect the car, and while it’s true a bad PCM could be your problem, it is not likely. They just don’t go bad very often. Having said that, I’m not sure I would trust the shop you mentioned as being able to fully test the PCM for problems. Maybe they can, maybe they can’t. If it were me, I would want further verification is all I’m saying...something which is possible if you have a DMM and are willing to do the testing yourself.

That’s all I have for now. I do wish you good luck with this, as I know first hand how difficult (and expensive) these gremlins can be to iron out. Unfortunately there’s not many shortcuts available for you. But if I think of any, I’ll chime back in and list them. ?

Nuke
 
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