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Discussion Starter #1
So I talked my buddy into joining the Challenger club. With promises of reliable old muscle car feel, but with all the modern benefits. He went and bought a 2015 Hellcat with 16k miles on it. Pulley swap and cold air intake on a Factory tune, and a aluminum drive line. After a week of owning it the drive line randomly would rub on exhaust. We fixed that. All is well my friend is happy again. Two days later the Voltage starts to jump around alot. (sorry at this point I don't know the range of it) Tested battery and it was bad. Ok I get that only 16k miles on a 2015 it sat alot. Replace battery np. Voltage is still jumping around. Car goes into limp mode power steering fails. We take it to local auto parts store to test the charging system. Guy says bad voltage regulator. Ok thats kinda weird but whatever lets replace the Alternator and we good. No wait the Voltage Regulator is in the Freaking PCM! So now what we have to replace the PCM just because of voltage regulator? Can it be repaired without losing the tune? Also this "bad voltage regulator" is based on some kid at some random auto parts store. Is there a inline fuse on the Alternator? Is there Anything else we can check?



Please help me with my Buyers Friend Remorse
 

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Ummm… I think it is the tune! I am no expert but it is the common denominator here. Everything is fine until you change something and then you look at everything except the thing you have changed that actually affects the problem?
 

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Discussion Starter #4
He bought the car with the Factory tune already done. If I recall on the paperwork the Pulleys and tune where done at around 8k. There is one CEL code P2174 Throttle actuator control system - Sudden low air flow detected.
I will attach a picture of what it does show on the dash. He just took it into the dealer today. (sadly where we live most dealers don't know much about hellcats) There is the U60 recall that needs to be done. So at this point he asked them to just diagnose the problem. If they say it is the Voltage Regulator, then he will have them flash it for the recall. Maybe somehow that will fix the issue... Either way the car gets flashed for the recall and will clear the VIN of showing it. This will sadly clear his tune also I assume. So then we are left with can the Voltage Regulator be repaired inside the PCM? Maybe the place that did the Factory Tune can reload the tune on the PCM if we send it too them. Otherwise I guess it's buy Diablosport PCM, and then find a local Tuner.
 

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Thanks for starting this thread for me Ons71.

All mods were done by the factory in 2017 in Peoria Arizona and the car was running fine when I bought it 3 weeks ago.

The voltage did jump around a bit, about 13 to 14. 2 volts when I gassed it or let off. Also the car would idle a little ruff after blipping the throttle (almost seems like a vacuum leak) when just sitting in neutral. Didn't seem like a huge issue.

Then a few days later I got a "battery saver on" message and check engine light. I was pulling into a parking spot when it happened and a lost power steering, that sucked!

The code is P2174-something about air flow/calibration: seems unrelated??

I also got an amber light that looks like a lighting bolt with these () around it, only faceing out.

I'm at a dealer now and they are diagnosing it. I'll update with more info when I get it.

Thanks for any help!
 

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FYI - there was a TSB regarding the radio where it would draw current with the battery off causing a low battery condition.


Sounds like P2174-LOW AIRFLOW/RESTRICTION DETECTED (INSTANTANEOUS ACCUMULATION) might be MAP or PCM related.
 

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I think the voltage reported on the instrument panel on my 2018 is usually around 14.0 -> 14.3 if I remember correct. 11.x is way too low. Mine is a V6 GT, but still - the voltage should be similar.

Also that )/( light is telling you there is an issue with the electroic throttle control, I believe.
 

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Discussion Starter #12
The dealer says it is the Alternator. 16k miles seems odd. But that beats buying a PCM and tune. So we will try that and see how it goes. Btw the stupid dealer also says that the power steering pump is out. They based that on no power steering moving it onto the lift. Never occurred to them that it is not working cause the car is not getting electrical power to the electric steering. I hate dealers so much. But lets hope they are right about the Alternator.
 

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Some HCat's have damaged their ground straps preventing load shed/causing other charging system issues, the fit is pretty tight on the cable...might wanna check the ground cable near the RR corner of the engine. Broken/damaged cable will make it look like the alternator is bad.

(Hopefully I resized this correctly):
 

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Some HCat's have damaged their ground straps preventing load shed/causing other charging system issues, the fit is pretty tight on the cable...might wanna check the ground cable near the RR corner of the engine. Broken/damaged cable will make it look like the alternator is bad.

(Hopefully I resized this correctly):

Thank you for this. I suspected a lose wire but could not find this ground. Man I hope this is it.
 

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Thank you for this. I suspected a lose wire but could not find this ground. Man I hope this is it.
Me too(!)

Fwiw- While PCMs can fail (although it's rare), 99.999% of the time this kind of thing is wiring related...which may look mimic controller failure, diagnostically speaking, leading you to think the PCM is bad.

G'luck, let us know
 

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Curiously question:

If I installed a high wattage aftermarket audio amp to the system, and it was causing the alternator to be at capacity, would this be able to explain why I was experiencing noticeable difference in performance?


Sent from my iPhone using Tapatalk
 

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What does at capacity mean? How do you know it’s at capacity? Anything you add to the cars electrical system will put a load on the alternator. If your amp is drawing down your voltage to less than 13 volts, then yes, I think it could definitely affect performance. You should buy a high capacity alternator if that is the case. You need a constant 13-14 volts for everything to operate properly and still charge your battery.
 

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Discussion Starter #19
Well the car has been at the dealer since the 1st. We asked them to check the ground strap. They say it is fine. I really wish we had the car so we could check it, or like I told my buddy just add a new ground to it just to be sure. But at this point we have to take the dealers word for it. I assume today is the first time they have even looked at it, after nearly a week of being there. So they are going to trouble shoot a bit more on it. But it looks like they are going to replace the PCM. If that does fix it then we have a whole other headache of getting it retuned, or buy a diablo. The only good thing about replacing the PCM is that it will take care of the PU60 recall. I hope for my friends sake that this will fix it. But my heart tells me its still a wiring problem.
 

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With the low voltages you stated I am surprised the IBS (intelligent battery sensor - located on the negative battery terminal) did not trigger the PCM to go into a battery saver mode. Hopefully the dealership actually diagnoses the problem instead of throwing more parts at it.
 

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