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Check Charging System Message

Ok, I was getting the Check System Charging warning last weekend at MPH. The message appears in the message center and the red battery light comes on in the dash. It would come and go and was intermittent. When it was in the shop for the new slave cylinder all systems tested out fine. The alternator was putting out the correct voltage and the belt was in good condition. I was out driving around tonight and it came on every time I got in the car. It wouldn't come on at key on but would come on after a few minutes of driving. I'm getting 14.1 to 14.4 volts from the battery while driving and it doesn't go outside those values so it's obviously charging fine. What the heck could be causing it ???

It's really annoying since it's a red light and even if you clear the message, it just keeps coming back. I'm heading to Road America next Sunday and it's a 9 hour pull so will not be the least bit amused if my alternator craps out and I'm out of commission again. Any ideas out there? I'm planning to run it into the dealer on Monday as soon as the light comes on so they can see it in action this time. It didn't do it while they had it in for the clutch.
 
713
70
Do you have a dc ammeter and will it read pos and neg? When an alternator is charging the battery the flow of current will be going into the battery. When it is going it will be flowing out of it. Sometimes as they are going it can happen intermittently.
 
Jza1736 said:
Do you have a dc ammeter and will it read pos and neg? When an alternator is charging the battery the flow of current will be going into the battery. When it is going it will be flowing out of it. Sometimes as they are going it can happen intermittently.
I don't have one. I'm picking up voltage from OBDII on my Aeroforce gauge. I would think it it's failing, even intermittently, I would see a drop in voltage as I continue to drive wouldn't I? I am concerned it's failing though, but if I can get the message to kick in and drive it into the dealership while it's doing it, they may be able to detect what you're describing.
 
713
70
I would think if it says it has 14~ volts the alternatir is ok. Although I wouldn't trust the computer I would verify with an outside tester. I'm sure the dealer will do that. Good luck Gary. Let us know what happens
 
Thanks for all the suggestions guys.

Blazn - I tried the wire testing but wasn't able to get it to do it that way. I'm sure there are some wires I missed but I tried the wires and grounds to the battery and alternator amongst many others.

Jason - That's my thought too. If it was an issue I should see a drop in voltage. The dealer did use their tester on the battery and alternator last week when it was in for the clutch and it all tested out OK.

06mach1 - I inspected the belt and so did the dealer and nothing seemed out of the ordinary. I'll have them double check that again too though.

I tried to see if anything was up with TK (wishful thinking). I went through 3 drive cycles today on the regular key and never popped the warning. Each cycle was about 15-20 minutes and included some WOT (with my wife in my ear a couple times :eek:) Upon leaving the gas station I tried TK and popped the warning within a minute. It went off after about 5-10 more minutes. I thought maybe I was on to something so I stopped at the end of an interstate ramp, turned off the car and restarted with the regular key. The warning came on after a minute or two, then turned off after a few more minutes. It just seems totally intermittent. Voltage the whole time ranged from low-to-mid 13s to 14s. ???
 
superhero said:
Gary, could the altenator be getting hot and affect the voltage out put on it?
Possible I guess but it's happening just cruising like a Prius on the street too. I would think if it's dropping output, the voltage from the battery would drop as I'm driving. I'll try and get it to happen today and whip into the dealership.
 
I got it to come on this morning and saw the voltage drop from 14.1-14.5 down to 13.0-13.4. I wheeled into the dealer and left it running while we pulled a voltage test off their handheld and it was 13.6 so the battery's fine. I left it with them to run a diagnostic on the alternator output. My bet's on a failing alternator. We should know this afternoon.
 

ArizonaBOSS

Because racecar.
Moderator
8,624
2,553
Arizona, USA
Dunno how it applies to the 5.0 variants, but a faulty alternator was one of the most common failures on the 4.6L S197s, even showed up as "cam position errors" etc trouble codes.

Good luck man.
 
ArizonaGT said:
Dunno how it applies to the 5.0 variants, but a faulty alternator was one of the most common failures on the 4.6L S197s, even showed up as "cam position errors" etc trouble codes.

Good luck man.
I had two go bad on my GT500 so a logical conclusion ;)
 
Well that really chaps my.....or is it chaffed? Actually I'm glad that our upgraded alternator didn't fail.

CHECK CHARGING SYSTEM ERROR MESSAGE STILL COMING UP OFTEN |
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| 2. CAUSE : ROAD TESTED. OCNFIRMED. CHECKED CHARGING SYSTEM-14.35 VOLTS. |
| CHECKED WIRING FOR ALTERNATOR-FOUND TWO WIRES CHAFFED. |
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| 3. CORRECTION: REPAIRED WIRES CDC10-DV-DG & CDC15 VT AT CONNECTOR C102A. |
| RECHECKED. ROAD TESTED OK.
 

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