Check Charging System

rainjacks

rainjacks

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I'd like some quick verification of my thoughts. Yes, I've searched and found a few possibilities. I thought the details of my problem might help narrow it down.

A few months ago in the dead of winter I replaced the original battery.

Today while idling at a stop light the "Check Charging System" message showed up. As soon as I get on the gas and the RPMs climb even slightly the message goes away.

I can replicate the problem by sitting with the car in park, stereo on, foot on the brake so the brake lights are on. With the car idling the warning light will turn on after a short amount of time. Rev the engine slightly and it goes away. Wait a little bit and it comes back.

I am going to check all of the cables including the one in the wheel well. But, I am guessing that I will soon be purchasing a new alternator.

Any thoughts?
 
Yup, definitely looking like a weak battery. If you have a DMM why not check the voltage of the battery while its resting.

Also if the battery looks like its sitting good in the 12 volt + range - I would take a look @ the alternator, turn the car on and see what voltages your getting while the alternator is charging. if its not doing a good 14 volts or close to, you have a dying alternator.


But I would check the battery first, as it is more logical to replace - and running a dying batt will definitely strain your alt.
 
It'll be the alternator, not the battery. With the engine running, all of the electrical load should be supplied by the alternator, not the battery. In particular, it sounds like the brushes/slip ring in the alternator are worn out.
 
A weak battery can still run a car poorly (as hes describing).


But yes it looks to be a problem with the alternator, but no sense in just replacing parts without checking the battery first.
 
Andrizzle said:
A weak battery can still run a car poorly (as hes describing).


But yes it looks to be a problem with the alternator, but no sense in just replacing parts without checking the battery first.
Click to expand...

Any battery with a fault severe enough to cause an operational problem (internal short, or completely open cell) would be unable to start the car in the first place. Listen to the electrical engineer. It's not the battery.
I should add that the LS's "Check Charging System" message specifically is only triggered by a fault detected in the alternator, or the wiring to it. Other cars you may have had experiences with, may operated differently.
 
The specific troubleshooting steps for an intermittent "check charging system" indication is:

PINPOINT TEST F: THE CHARGING SYSTEM WARNING INDICATOR FLICKERS OR IS INTERMITTENT
Test Step Result / Action to Take
F1 CHECK FOR LOOSE CONNECTIONS

* Key in OFF position.
* NOTE: If the I circuit 10-BA25 (GY/RD) is open or short to ground, the generator does not function. If the engine speed exceeds 3,000 rpm, the generator self-excites, and begins to function normally (the battery light turns off and the generator operates normally) until the engine is turned off. This is a limp-home mode for customer safety.
* Check all generator, battery, rear BJB connections for looseness, corrosion, loose or bent terminals, or loose eyelets.
* Are all connections clean and tight?

Yes
If the charging system warning indicator flickers, INSTALL a new instrument cluster. REFER to Section 413-01 . If the charging system warning indicator is intermittent, GO to F2 .

No
REPAIR as necessary. TEST the system for normal operation.
F2 CHECK FOR LOOSE FUSE CONNECTIONS

* Key in START position.
* Check the rear BJB fuse 15 (5A) in A circuit 30-BA25 (RD) for looseness by wiggling the fuse and noting the charging system warning indicator operation.
* Does the charging system warning indicator flicker?

Yes
REPAIR the loose fuse connection(s) as necessary. TEST the system for normal operation.

No
GO to F3 .
F3 CHECK A CIRCUIT 30-BA25 (RD) FOR LOOSE CONNECTIONS

* Key in OFF position.
* Connect a fused (15A) jumper wire between the generator C102a-3, A circuit 30-BA25 (RD) (backprobed) and the positive battery terminal.

* Key in START position.
* Note the charging system warning indicator operation.
* Does the charging system warning indicator illuminate?

Yes
GO to F4 .

No
REPAIR the loose connections in A circuit 30-BA25 (RD). TEST the system for normal operation.
F4 CHECK I CIRCUIT 10-BA25 (GY/RD) FOR AN OPEN OR SHORT TO GROUND

* Key in OFF position.
* Disconnect: PCM C175c.
* Disconnect: Generator C102a.
* Measure the resistance between the PCM C175c-19, circuit 10-BA25 (GY/RD), harness side and the generator C102a-2, circuit 10-BA25 (GY/RD), harness side; and between the PCM C175c-19, circuit 10-BA25 (GY/RD), harness side and ground.

* Is the resistance less than 5 ohms between the PCM and the generator, and greater than 10,000 ohms between the PCM and ground?

Yes
INSTALL a new generator. REFER to Section 414-02 . TEST the system for normal operation.

No
REPAIR the circuit. TEST the system for normal operation.
 
Yup, I saw this in a previous post about electrical issues. Thanks for the input. It is just one of those things where I know what the answer is, but I am hoping that someone will give me a different (less expensive) answer. Checking the battery is easy enough so I'll do that before I purchase the new alternator just for grins.

Anybody know of a good place to get an alternator? Is there a better/higher output one that I should consider?
 
I don't see how checking the battery's voltage is a big task, this will even tell you if your alternator is charging right...

I don't see how anyone with 5 minutes wouldnt take the time to look @ a reading from placing two prongs onto the battery terminals - and instead they go out and just buy a new alternator.


And that troubleshooter you just posted lists all those tests to do... and you are saying it is 100% alternator. What gives?
 
rainjacks said:
Yup, I saw this in a previous post about electrical issues. Thanks for the input. It is just one of those things where I know what the answer is, but I am hoping that someone will give me a different (less expensive) answer. Checking the battery is easy enough so I'll do that before I purchase the new alternator just for grins.

Anybody know of a good place to get an alternator? Is there a better/higher output one that I should consider?
Click to expand...

Check out Mechman alts

I have a 250 amp alt from them and it works great, also dyno sheet shows over 280 amps peak output.
 
Testing battery voltage when the engine is running determines one thing, and one thing only, and that is if the alternator is producing the proper voltage to charge the battery. You can have a completely shot battery and still see 14v at the posts, because the battery essentially does nothing once the engine is running.

When the engine is running the alternator supplies current to the car. So if you test the battery while the car is running and you get 14V, it's because the alternator is producing 14 volts. Disconnect the positive cable from the battery, and you'll still get 14V on the cable, even though it's not connected.
 
The battery is the stableizer in the system... If the alt was directly supplying current to the cars accessories, things would be haywire. You need a healthy battery to be charged by the alternator or things are going to be screwy like the OP is saying...

Alternator ---> Battery ---> Car components
 
That's true, but all it does is make up for the small drops and fluctuations in the current that occur as the alternator spins.
 
Well, the symptoms have disappeared for now. I got the car out this morning and I couldn't get it to give me the message no matter how hard I tried.

I'll keep you all posted . . .
 
I never said not to check the voltage. The OP should do that. I said, and I stand by it, that a bad battery won't turn on the "check electrical system" message or light. That's just the way it is.
Doing a voltage test on the battery determines almost nothing about the battery. The correct way to test a battery is to (1) charge it up completely, and (2) connect it to a proper load test outside of the car. There are less exact tests that will give you some idea of the battery condition. One of those is just to see if it can start the car. It does, so it's not the battery. It's going to be the alternator, the wiring to the alternator, or the engine computer. The alternator is the wear item, so it is the most likely suspect.
It's stupid for us to even be debating this back and forth. We're at the point where we should just wait for rainjacks to tell us what the repair ended up being.
 
rainjacks said:
Well, the symptoms have disappeared for now. I got the car out this morning and I couldn't get it to give me the message no matter how hard I tried.

I'll keep you all posted . . .
Click to expand...

Don't worry, it'll be back. However, you probably would be wise to wait for it to act up again before trying to get it fixed. Intermittent problems are the hardest to troubleshoot. It's much easier to diagnose a problem while the failure is happening. Good luck. BTW, the stock gen II alternator is good for 70 amps at idle, and 134 amps when the engine is at or above 2000 RPM. Unless you have a big sound system, you shouldn't need more than that.
 
I'm sure it will come back. I've got a Gen1 and my ford buddy says the shop manual calls for 1 hour, so I'm not thinking the change will be too difficult. I can get a Ford replacement one from him for right around $200. I've got a stock sound system at this point and don't see anything else on the horizon.

thanks for the help guys.
 
Yea id check ur alternator, i just had tht exact problem yesturday and my alternator died on me!
 
I'm going to my Ford buddy's house this weekend. He's going to bring home the diagnostic computer. We'll flash the car up to the latest version of the software, check out the ABS so I can figure out what is causing the advancetrac warning, and test out the alternator all at the same time. Of course, if the alternator issue is intermittent that might not help.
 
PCM flashes are usually done with the engine off so you only have to worry about your battery going dead. :p

Alternators produce less when they get hot, so unless you drove the car for a half hour first, it would stand to reason that the light didn't come back if the alt is right on the fringe of going kaput.
 
Alternators produce less when they get hot? That's a new one on me. If anything they'd produce more assuming the regulator is out to lunch. As heat increases, the copper's resistivity goes down so more current would flow. I can't honestly see how this could be a true statement unless the regulator is bad. Not trying to be ignorant, but this simply isn't true.
 
It's a true statement, the rule of thumb is about a 10% decrease in output. If you don't believe it, you'll have to test it for yourself, as I am not certain of all the physical reasons behind it. I do know that the efficiency of the diodes drops as temperature increases. (In fact, diodes are often used as temperature sensors because their properties vary predictably with temperature.)
If memory serves, GM has had more problems with alternators overheating than Ford. Some of theirs are even water cooled.
 
OK, got the PCM flashed and we looked at all of my codes. The alternator was working fine while I was there but my friend agreed it is going to die. So, I will look for another one. At the same time we looked at the advancetrac message and found that it wasn't a speed sensor at all. It is a problem in the Advancetrac module. Essentially the computer that controls it.

On a happy note the car seems to be shifting a little more firmly with the flash. But it could just be the placebo effect.

On a sad note I will be in the market for a few parts.
 
I could be wrong, so please double check this...
I think that replacement of the advancetrac motion sensor module requires a calibration procedure that requires dealer equipment to trigger.
 
joegr said:
I could be wrong, so please double check this...
I think that replacement of the advancetrac motion sensor module requires a calibration procedure that requires dealer equipment to trigger.
Click to expand...

Yes it does. You have to use the dealer computer to pull data from the original module and put it on the replacement. That is why it is great to have a friend like mine who has the computer to do the work. :D
 
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