Alternator burned now problems ensue?

Battery voltage is at 11.54 engine running cold start. Purge unplugged. Just started the car. We’ll see how long it runs. Is it possible I bought a bad VVT solenoid from Napa?

Okay, it’s still running but I’m going to shut it off as it’s extremely low on fuel and I want to be able to get it on the trailer if needed.

Update: I’ve replaced the battery and alternator with all new, also replaced the VVT Solenoid as well as the jumper harness. The car stays running now but P0013 is persistent and battery light is flashing/on. I’m leaning towards a fried pcm but I can’t be positive. I did find a fusible link in the alternator wire and did a voltage test on both sides of the link, it’s registering voltage through the link. No alternator fuse in the fuse box. I think it’s a pcm issue because the CEL and persistent P0013 code as well as the battery light. The battery light indicates a fault in the charging system and the p0013 code says there’s a short or an open somewhere, I can’t find a short, bad ground or burnt/broken wire. There is continuity to the vvt on the ground and positive. I’m hoping there’s power making it to the vvt but don’t want to mess things up worse trying to check for voltage as I’d have to take the intake off again and probe for voltage on a brand new jumper harness.

I’m at a total loss here now, so my option now is to take it to the stealership for further diagnostics.

Any suggestions or ideas are very welcome and I appreciate all of it.

Hi there. I just want to make sure I am reading your update correctly. When you say you tested the voltage for the link, did you use the meter as pictured below? If so, a voltage reading would indicate an open circuit. The fuse link is likely burned out.

I did the voltage test with the car off and put the black/ground to ground and positive/red probe into the wire just before the link, it showed battery voltage of 11.5 or so, then probed again just after the link and it showed the same voltage.

I didn’t put the ground to the positive for the test, I’m using a loaner multimeter and didn’t want to end up frying it.

I meant to get a picture of the link but forgot. But this image is basically what it looked like.

Okay, thanks for the clarification. In this case the fuse link tests okay. What is the battery voltage with the engine running now?

With the engine running it first showed 12.9 V, but letting it sit and idle, it dropped charge to 10 and continued to drop.

Alright, the alternator is not charging. I found this excerpt in a service manual: Voltage is monitored at the B+ terminal stud to insure it is connected. If the B+ cable is loose, the PCM will shut down the generator field. Because of this new feature, pin-2 of the field connector is internally connected to the B+ terminal.
So, I would double check that all of the connections from the battery post to the alternator are clean and tight. Then I would carefully back probe the GY/RD wire at the alternator for voltage with the key on engine off and with engine running as long as it is safe to do. Red lead to connector, black lead to ground. You should have battery voltage.

If that is ok, I would check for a signal on the BR/PK wire at the alternator. A test light connected to battery positive and back probed to the alternator connector should flicker with the engine running. This shows that the PCM is trying to command the alternator.

Here are some links that might help with back probing:

https://youtu.be/g2ST8w_0w-Q

https://youtu.be/op6Djd9PbIc

Again, please be careful of getting your test equipment tangled up with moving parts when you test with the engine running.

I towed the Jeep to have an ASE certified diagnostic ran so they can test the PCM, alternator, as well as check pwm signals and actuate the solenoids, valves, etc. There’s no way I can afford to have them do any of the labor or buy their parts, so I figured the next best thing is to have them diagnose the expensive parts like PCM and then I’ll source the part myself and install, unless it needs programming. Then I’ve no choice but to save up. Though I did find a PCM from AutoZone at a much nicer price and they say it’s plug and play so that’s my backup plan for that part. But I digress, that’s all dependent of the results. I will be getting the car back hopefully soon and with deeper knowledge of what or where the issue is and combining that with all of everyone’s extremely appreciated time, help, and advice I’ll be able to piece this back together.

On another related note, I cannot find a name or # for the “engine harness assembly”, so I’m trying to source parts that are likely the culprit to cover my bases. This harness assembly starts from the PCM and wraps around the intake manifold but has “forks” everywhere that go to all the electrical. It includes the MDS/VVT solenoid jumper harness. The MDS/VVT jumper harness clips into the main assembly. I’m trying to find said assembly just in case it’s a short somewhere in that because I am terrified of tearing into that wiring so I’d rather just replace the whole thing if possible. This is the MDS/VVT jumper harness part # that I’ve already replaced 05148163AE. Looking for the rest of the assembly that part plugs into.

@ AL514
@MATHGEN

Thank you for your time and help with this. The problem has been fixed. A new PCM was the solution.
I took it in to the dealership on 4-28-2023, waited the UAW stike out and finally got the PCM in on 11-28-2023. They had it installed and it’s now in my driveway again. Though the TPMS light is on and shows the fr flat line and rr continuously fluctuating. The light flashes and then stays lit. Thinking it’s just the sensors but will diagnose in the daylight.

Thanks again for all your help fellas, much appreciated!

Hi,

Thanks for the update and we're glad to know it is taken care of. I read back through parts of the thread. The voltage regulator is integral to the PCM. It is a voltage-regulating circuit located within the Powertrain Control Module PCM. Based on what has happened and you not getting a charge, the PCM is certainly the likely cause.

Was anything other replaced? I'm just interested in knowing.

Joe

JACOBANDNICKOLAS,

Yes, I replaced the whole charging system before I replaced the PCM.
Battery, alternator, jumper harness, and VVT solenoid. After bashing my head against walls and getting nowhere with removing a P0013 code that seemed to be permanent, I had come to the conclusion that when the alternator fried, it also took a good bite out of the PCM, because it was showing codes that belong to Caterpillar and Prius code C1600, as well as the stuck P0013 code along with ac relay codes and a few others. Under the intake manifold is the VVT and jumper harness, the harness and top of the block has a thick foam padding that mice love to nest in. Mine was nested in and the mice had chewed some of the plastic insulation off the jumper harness and it was showing copper, not chewed through, just stripped a little bit but enough to potentially cause problems. All in all, I spent about 20-30 labor hours as well as about $2,200.00 to fully fix it.

It’s just like new now and no more x-mas tree lights in the dash.


LepriKaan

Hi,

Thanks for the update. I don't like the alternator being regulated via the PCM, but Chrysler has done it for years. The sad thing is in most cases when there is an alternator-related issue, it damages the PCM.

Regardless, I'm glad to know it has been taken care of. Please feel free to come back anytime in the future.

Take care and Happy Holidays.

Joe

Joe,

So, do you think it’s possible to put in a resistor or a voltage regulator of some kind between the PCM and alternator as a precaution?

Something like this:
https://mopar1973man.com/topic/15349-electrical-article-alternator-and-pcm-protection/

Hi,

Anything is possible, but you have to be careful. Remember, the PCM needs to see fully what the alternator is doing and adjust accordingly. If you install a register between the two, that cuts power down to the PCM which will in turn force the alternator to work harder. In my mind, that would lead to new problems.

Take care of yourself and let us know if you have other questions.

Joe