I continue to get this message on my car. The dealership said it is not stored in teh computer. They indicated that they can not help me. Have you ever seen this. I replaced the alternator and the battery. Any ideas?

 

I replaced the alternator and the battery. Any ideas?... you did this before the problem or after the problem...
Meaning:
You had a constant charging system fault, so you replaced the alternator and battery to fix it.. or

after you replaced the alternator and battery you started to get Charging system fault.

 

I have seen this message occasionally with no ill effect to the vehicle. When it was new I had the alternator replaced as I had indication of a discharging battery. Since then I see the charging system fault maybe once a month without any ability to reproduce it, but it only happens immediately upon starting. When do you see it?

 

The following is a quote from my service manual....

Volume 3 Page 6-393 Engine Electrical

You may have replaced the battery - but is the battery good? Have you had the battery load tested? There are two pages of diagnostics to perform that I cannot replicate here. You might check the battery and if you know someone with a service manual - check pages 6-393 through the top of page 3-396 in volume 3.

Hope this helps....

 

This may not be your issue,but it was mine

Loose starter cable..........

The voltmeter continually dropped,to the point of the dic completely blacking out( I was on my way home at the time),then it started missing,,,,,,,

I really thought it was at least a battery but probably an alternator


To my surprise it was just this loose connection

I hope yours is this easy

 

I've been getting this message now and then at startup but haven't had any electrical problems until yesterday. The battery is dead and I tried to jump it but was unsuccessful. It's going to the shop today.

 

I have this every time I drive the car now for the past 9 months or so. I've replaced the alternator twice, battery 3 times, changed out the starter etc. I've been reassured there is no issue w/ mine and it comes down to just replacing parts to see what helps which is very $$. They said next on the list is my instrument cluster, so I decided to give up. It all began when my starter went and later the alternator was replaced which was overcharging my system. I think it fried something.

Good luck.

 

You have the wrong alternator in your car....If you had a credible dealer, they would have told you this.... Problem is they dont realize that your new alternator is not communicating with your old PCM... I'm guessing that you now have an alternator that puts out more than 110 amps.. You PCM is expecting to see a full duty charge of 110 amps>

The alternator is very specific to the PCM...
GM's upgraded alternator is a poor fix... while it is functioning fine... the PCM thinks it isnt...

The only way to Fix this problem for sure is to have the original alternator rebuilt..But it just cant be a 110 amp GM alternator it has to have the specific part number GM 10246634 because of the specific switching found in this alternator, that talks with the PCM
Good Luck and I apologize for the poor service found at your dealership.
Bill aka ET

I've posted this many times, and you may find it of some insight.

The PCM monitors the alternator through the red and grey wires The L-terminal circuit from the generator is a discrete circuit (a discrete circuit has no splices and only one source and destination) into the PCM. The PCM applies ignition voltage to the generator L-terminal circuit. A small amount of current flows from this circuit through the generator windings to ground to create a magnetic field which starts the generator process. When the generator is at operating speed and producing voltage, a solid state switch for the L-terminal circuit in the generator opens and the PCM detects that the initial startup current flow has stopped.

The PCM expects to detect low voltage on the L-terminal circuit prior to the generator rotating at operating speed and conversely expects the circuit to be at ignition voltage potential when the generator is operational. When the PCM detects a fault (circuit shorted to ground, or circuit shorted to voltage), the Driver Information Center will display Charging System Fault.

The generator has an input to the PCM called the F Terminal to indicate the percentage of total capacity that the generator is producing. This signal is detected by the PCM as a duty cycle from the generator and displayed on the scan tool as a percentage. The PCM can monitor the generators output under all conditions to determine if it is functioning normally.

When there is low demand from the electrical system on the generator, a low duty cycle percentage will be displayed. As more accessory load is placed on the generator, the duty cycle output detected by the PCM will approach 100 percent. A normally functioning generating system will never reach 100 percent as indicated on the scan tool.

The L and F terminals are the red and grey

I hope this helps...

 

What an excellent and informative post by E-T. Thank you Bill! I now know that if I experience an alternator failure in my car - I will be sure to either have my alternator rebuilt to the same standards or make sure that I get the exact replacement - part number GM 10246634.

Thanks Bill, I learn something from you every time I cross your path.

Randy

 

I just got the "Charge System Fault" message last month and was unsure as to what it meant. Thanks to ET, I know exactly what to do. The man never ceases to amaze me

 

Bill is the BEST!!!

 

I had and still have an intermittent Charge Fault message since the car was new (MY 04). My car has had no problems with charging and I can actually generate the message. If I release the key as soon as the engine starts the message appears, real quick release. Apparently there is a race to the PCM, if the key is released quickly the starting voltage drop and subsequent recovery sends the wrong message to the PCM. I had 3 dealers ring the system out and all found no problem. Hope this helps.

 

Thanks Bill (ET)
I just printed this off and will keep it with my service manuals as a ref. in the future.
Thanks again,