Battery Not Charging

4722 Views 20 Replies 11 Participants Last post by ChallyTatum, 3 h ago

lopez.b76

Discussion Starter · Mar 3, 2022 (Edited by Moderator)

I was driving then my car, it started smoking from the alternator, then the car died completely- no power. Replaced the alternator and battery but the alternator is not charging battery. My mechanic says it's the PCM. Is that right? Please advise.

1 - 20 of 21 Posts

Nuke

· #2 · Mar 3, 2022

lopez.b76 said:
I was driving then my car started smoking from alternator they car died completely no power. Replaced the alternator and battery but alternator not charging battery my mechanic says it the CPU is that right? Please advise.

The voltage regulation of the alternator’s output is handled by the PCM. So if the car’s charging system is malfunctioning now, and the problem is a lack of voltage regulation, that would require a new/different/working PCM to fix the problem.

Having said that, I doubt your problem is a bad PCM. Ask your mechanic what happens after he replaces the PCM and the problem remains? In fact, tell him he gets no money for parts or labor until the problem is proven to be resolved.

He will be more reluctant to fire his parts cannon in that scenario, I would hope.

ChallyTatum

· #3 · Mar 3, 2022

lopez.b76 said:
I was driving then my car started smoking from alternator they car died completely no power. Replaced the alternator and battery but alternator not charging battery my mechanic says it the CPU is that right? Please advise.

What year Challenger? There was a recall on the alternator for certain 2011-2014 models.

If your Challenger is within that time window you can check if it has ever been recalled.

Look for Vehicle Recalls | Official Mopar® Site

Search vehicle recall information by VIN or sign in to your Mopar® account to see recall information related to your Chrysler, Dodge, Jeep, or Ram vehicle

www.mopar.com

Hal H

· #4 · Mar 3, 2022

when the alternator went, it could have taken out several different items

a local guy had an alternator seize and short out, either had issue with TIPM or PCM afterward. Would have IP cluster lights, but no cranking

lopez.b76

Discussion Starter · #5 · Mar 3, 2022

Could it be the wires that connect to alternator that burn or is the PCM? Car won't start and it won't charge the battery

Wm. Internet Rock DJ

· #6 · Mar 4, 2022

If the alternator is not producing the voltage and amperage, it won't charge. If it's over charging, it will cause issues with electronics. Check your car for recalls.

Look for Vehicle Recalls | Official Mopar® Site

Search vehicle recall information by VIN or sign in to your Mopar® account to see recall information related to your Chrysler, Dodge, Jeep, or Ram vehicle

www.mopar.com

Bucko1

· #7 · Mar 4, 2022

I can't say for sure on our Challengers and/or what years, but most alternators and starters used fusible links (a wire that burns like a fuse) to protect the alternator/starter in an event of overload or short.

Starters and alternators are traditionally wired to to a battery, and don't pass through a fuse panel/breaker, so fusible links are used to protect any potential damage or fire to a vehicle in the event of a short circuit from them.

Maybe this technology changed though. Seems out of line that a Powertrain control module (TCM) is the protection device for a faulty alternator. Expensive fuse.

Rockster

· #8 · Mar 4, 2022

lopez.b76 said:
I was driving then my car started smoking from alternator they car died completely no power. Replaced the alternator and battery but alternator not charging battery my mechanic says it the CPU is that right? Please advise.

Is the new battery fully charged?

Are the battery cables and connections at the battery and at the other end of the battery cables good? And as Bucko1 brought up if the battery/alternator cabling has any fusible links these must be verified as good.

The alternator plays no role in starting the engine. Once the engine is running battery voltage to the alternator (rotor) is controlled by the PCM to control alternator output.

If the voltage to the alternator is not present the alternator won't make electricity. The battery if it is healthy can keep the engine running a while but at best maybe a few minutes. But if a voltage test finds the alternator not generating 13.5V to 14.5V (ball park-ish numbers) a check to ensure the alternator is receiving power from the battery to energize the rotor is necessary. If the alternator is not receiving voltage the wiring has to be checked.

There may be other tests/checks but a Dodge tech should know what these are. The idea is to check until one finds the problem. It could be the PCM is at fault but you don't want to replace this unless you are sure it is not something else. And you want to be sure there is no short or other wiring problem that puts the new PCM at risk of damage.

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ChallyTatum

· #9 · Mar 4, 2022

lopez.b76 said:
Could it be the wires that connect to alternator that burn or is the PCM? Car won't start and it won't charge the battery

As I mentioned in my earlier post, what year is your car? Hard to help you diagnose your problem if you don't provide year and trim level. This is important as some year Challengers had a recall. (I mentioned how you can check in my earlier post) on the alternator...although since you have had a shop replace the alternator a dealership may not honor it.

lopez.b76

Discussion Starter · #10 · Mar 5, 2022

I have a 2010 Challenger Hemi 5.7.

lopez.b76

Discussion Starter · #11 · Mar 5, 2022

Rockster said:
Is the new battery fully charged?

Are the battery cables and connections at the battery and at the other end of the battery cables good? And as Bucko1 brought up if the battery/alternator cabling has any fusible links these must be verified as good.

The alternator plays no role in starting the engine. Once the engine is running battery voltage to the alternator (rotor) is controlled by the PCM to control alternator output.

If the voltage to the alternator is not present the alternator won't make electricity. The battery if it is healthy can keep the engine running a while but at best maybe a few minutes. But if a voltage test finds the alternator not generating 13.5V to 14.5V (ball park-ish numbers) a check to ensure the alternator is receiving power from the battery to energize the rotor is necessary. If the alternator is not receiving voltage the wiring has to be checked.

There may be other tests/checks but a Dodge tech should know what these are. The idea is to check until one finds the problem. It could be the PCM is at fault but you don't want to replace this unless you are sure it is not something else. And you want to be sure there is no short or other wiring problem that puts the new PCM at risk of damage.

my mechanic is saying he check all wires on alternator and battery car turns on with battery fully charged but battery gets drained. So he said it's the PCM.

Rockster

· #12 · Mar 6, 2022

lopez.b76 said:
my mechanic is saying he check all wires on alternator and battery car turns on with battery fully charged but battery gets drained. So he said it's the PCM.

Not sure what kind of electrical test is used to determine if the PCM is controlling power from the battery to the alternator to regulate the power output of the alternator. But if the mechanic says its the PCM then it is the PCM. Since it it is common for Chrysler (Dodge) vehicles to use the PCM as a voltage regulator if what output pin that is the voltage regulator goes bad the entire PCM must be replaced.

Thinking out loud I wonder if disconnecting the PCM from the altenator and feeding some proper amount of voltage to the alternator to confirm if the alternator can produce electricity and its population of diodes is working. The alternator produces A/C current and the diodes rectify this to cause the current to become direct and only flow one way from the alternator to the car/battery.

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TheOriginalEasyrider

· #13 · Mar 6, 2022

It's ridiculously easy to check to see if the alternator is charging the battery.

Personally, I'd be looking for a better, more trustworthy shop but that's just me. I have an independent shop that has several very good technicians and one who is very familiar with my car. He knows a lot more than I do and I kinda know a lot about mechanics and computers. So I pretty much trust what the shop tells me since I already do my own troubleshooting before I even show up there. So far, no surprises.

If you don't have a trusted shop to go to these days you are really up against it. Personally, what you are being told doesn't make a lot of sense to me.

Mediocre mechanics tend to blame the PCM for anything they can't figure out.

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Rockster

· #14 · Mar 6, 2022

TheOriginalEasyrider said:
It's ridiculously easy to check to see if the alternator is charging the battery.

Personally, I'd be looking for a better, more trustworthy shop but that's just me. I have an independent shop that has several very good technicians and one who is very familiar with my car. He knows a lot more than I do and I kinda know a lot about mechanics and computers. So I pretty much trust what the shop tells me since I already do my own troubleshooting before I even show up there. So far, no surprises.

If you don't have a trusted shop to go to these days you are really up against it. Personally, what you are being told doesn't make a lot of sense to me.

Mediocre mechanics tend to blame the PCM for anything they can't figure out.

I would hope the tech before he condemned the PCM made the necessary checks to confirm the PCM was at fault. The OP is certainly entitled to in a diplomatic way ask how the PCM was determined to be at fault. Really the tech should have offered up some brief description of what he did and how he arrived at his diagnosis.

Rockster

· #15 · Mar 7, 2022

Found this which might be of some interest to the OP. I have no experience with these devices.

Added: For models older I believe if you scroll on down you will find these.

External Voltage Regulator by-pass Kit, Chrysler Dodge Jeep and 2011 to 2014 Volkswagen Routan

Kit Gets your Alternator working again, Bypass Alternator Voltage regulator in the computer

alternatorparts.com

Sereno011

· #16 · 14 d ago

TheOriginalEasyrider said:
It's ridiculously easy to check to see if the alternator is charging the battery.

Mediocre mechanics tend to blame the PCM for anything they can't figure out.

It is NOT easy to test a modern alternator. Not only being PCM controlled, but have advanced electronics within the built-in regulator as well. Can't just full field using a paperclip like on a old Ford. Not to mention the today's battery monitoring sensors, can disable the charging outright. Lacking OEM service data it's another headache that can have you chasing your tail. Diagnosing takes time, requiring subscription fees for AllData. And an oscilloscope is nearly essential. Diagnostic time is $ the customer has to be willing to shell out for along with repairing whatever is needed. When it's an intermittent fault you may have no choice but to shoot the parts cannon.

Chrysler's are among the most complicated to boot. If disconnecting the battery while running it may stop charging outright and love to go into limp mode. If battery is too weak charging again can be disabled. May not stay running after a jump start. We'll always need mechanics for brakes and ball joints but anything 12V today needs an actual tech.

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ChallyTatum

· #17 · 14 d ago

Not to mention there is an IBS (intelligent battery sensor) on the ground side of the battery terminal connection that reports SOC and I believe temperature of the battery to the can bus.

Bucko1

· #18 · 14 d ago

Nuke said:
The voltage regulation of the alternator’s output is handled by the PCM. So if the car’s charging system is malfunctioning now, and the problem is a lack of voltage regulation, that would require a new/different/working PCM to fix the problem.

Having said that, I doubt your problem is a bad PCM. Ask your mechanic what happens after he replaces the PCM and the problem remains? In fact, tell him he gets no money for parts or labor until the problem is proven to be resolved.

He will be more reluctant to fire his parts cannon in that scenario, I would hope.

Excellent advice. It sickens me when a service advisor informs me that an expensive part is required to remedy a fault. I too have asked them that if the issue still exists, there is no charge? They then stare at you like deers looking into headlights.

Tharkus

· #19 · 12 d ago

2010 RT 5.7

Did you ever get this figured out? I am having the same problem, my mechanic said either PCM or TIPM. I changed battery at first, assuming it was bad as it was the original. Changed the alternator, because it had a bad diode. Any help would be appreciated.

pinger775

· #20 · 8 h ago

ChallyTatum said:
As I mentioned in my earlier post, what year is your car? Hard to help you diagnose your problem if you don't provide year and trim level. This is important as some year Challengers had a recall. (I mentioned how you can check in my earlier post) on the alternator...although since you have had a shop replace the alternator a dealership may not honor it.

My car is a 2016 dodge challenger srt 392 and I’ve already went through a few alternators anc I’m still losing voltage and my car ends up dying my battery’s are good too

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