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Discussion Starter #1
About three weeks ago while driving home at night out of the blue the battery light came on and check charging system warning message displayed. Looked at my radar detector which I have displaying volts and was reading 12.1. Normal voltage for the car is 13.8-14.1 at idle with no load or heavy load. Was about 15 mins from home so I turned all accessories off besides headlights. Let the vehicle sit for a few days and started it up, no problems. Drove it for two days and the same issues came back up but only stayed on for 4-5 mins then everything went back to normal. It did this several times more over the next week, then had another two day stretch with no problem.

Car has 134k miles on it so I decided to start with a few simple things first before taking it to the dealership (has basic ESP warranty), replaced the power steering and serpentine belt along with the tensioner. Made no difference as the charging at times seemed low for normal 13.4 but I know that's still in spec. New Ford battery was installed in April of this year so I knew the battery was good (I tested it anyways), load tested the alternator and it was good.

The check charging system message came on again but it was going on and off multiple times the last 30 mins of my drive. After that episode I decided to take it to the dealership. Dropped it off this morning and service writer just called me and said that there is an issue with the gauge cluster and my brake lights were acting up. I asked him "do those things have anything to do with the check charging system message and volts dropping to 12 so randomly?" He said no and then told me it would be $860.13 to replace the gauge cluster, reprogram the computer and keys. I said no, that's okay. I knew it wouldn't have an episode while it was there because it was so random when it happened while I was driving it.

95% of the time I enjoy driving this car cause it rides smooth, comfortable and nice and quiet compared to my other vehicle but I guess it knows it's paid off so it wants to act up. Battery & alternator are good, all the pullies are good, checked/cleaned every plug connector I could find as well.

Anyone else have the check charging system issue on their 2008-2009?
 

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Just an update, the problem is still going on, Check Charging System message still randomly comes up, it can stay on for less than two mins and the longest has been about 44 mins. Can come on everyday for a week or wont during several days which is frustrating! Got some info to enter the Engineering Test Mode so I can have the PCM read battery voltage (charging voltage) displayed in the message display screen. Over the past few months the voltage shown when the Check Charging System message comes up as slowly gone down, now when it happens voltage reads out around 11.5 . Last month FINALLY a DTC code of P0620 came up "Generator Control Circuit Malfunction", I plan on taking it to the dealer once I have a day off of work next month and will leave it with them. I don't care if a tech has to drive it around for a week as their personal vehicle, Ford won't do anything unless they see the message for themselves even with the DTC in the system memory.

It's either the alternator (regulator, bad brush, etc), wiring from alternator to PCM, the PCM itself or the instrument gauge cluster. If it's the alternator or part of a wiring harness that will be covered by the warranty, not sure if the PCM is covered and I know the instrument gauge cluster is not.
 

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Just an update, the problem is still going on, Check Charging System message still randomly comes up, it can stay on for less than two mins and the longest has been about 44 mins. Can come on everyday for a week or wont during several days which is frustrating! Got some info to enter the Engineering Test Mode so I can have the PCM read battery voltage (charging voltage) displayed in the message display screen. Over the past few months the voltage shown when the Check Charging System message comes up as slowly gone down, now when it happens voltage reads out around 11.5 . Last month FINALLY a DTC code of P0620 came up "Generator Control Circuit Malfunction", I plan on taking it to the dealer once I have a day off of work next month and will leave it with them. I don't care if a tech has to drive it around for a week as their personal vehicle, Ford won't do anything unless they see the message for themselves even with the DTC in the system memory.

It's either the alternator (regulator, bad brush, etc), wiring from alternator to PCM, the PCM itself or the instrument gauge cluster. If it's the alternator or part of a wiring harness that will be covered by the warranty, not sure if the PCM is covered and I know the instrument gauge cluster is not.
Should be straight forward to diagnose:

1. I would rule out the Instrument cluster since:
- you already displayed the PCM voltage and it is low. The IC gets the voltage data via CAN and displays it
- You already have a DTC in the PCM which also confirms that something within the charging system is bad

2. You can rule out the PCM easily by:
- Taking a Multimeter and measure the voltage at the battery as soon as the problem occurs
- If its matching the voltage shown in the PCM data stream on the IC it is 99% sure that you have a problem within your charging system which can be either the generator, regulator or cabling as described by you.

Hope that helps - good luck with your Dealer:fruit:
 

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Discussion Starter #4
Should be straight forward to diagnose:

1. I would rule out the Instrument cluster since:
- you already displayed the PCM voltage and it is low. The IC gets the voltage data via CAN and displays it
- You already have a DTC in the PCM which also confirms that something within the charging system is bad

2. You can rule out the PCM easily by:
- Taking a Multimeter and measure the voltage at the battery as soon as the problem occurs
- If its matching the voltage shown in the PCM data stream on the IC it is 99% sure that you have a problem within your charging system which can be either the generator, regulator or cabling as described by you.

Hope that helps - good luck with your Dealer:fruit:
I did check the voltage at the alternator and battery when the problem occurred as I was pulling into work one time, IC was showing 11.9v and that's exactly what my DMM showed as well.

With it being PCM voltage regulated made me think it could possibly be the PCM as well but the more I think it about things are pointing back at the alternator or at least the regulator being at fault.

Just hate to waste another $80-100 on diagnostic charge just to be told nothing is wrong when clearly there is.

I'll report back after I go to the dealer that I use to work for, bought the car from and know the owner & family well still, maybe that will help grease the squeaky wheel of something being done this time. Previous dealer I had check it out was 15 mins from my house compared to 90 mins away from my old dealership.
 

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Electronics such as the pcm very rarely fault, but when they do, they DO. I'd suggest alternator is the issue. Is the serpentine belt possibly slipping?
 

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I checked the workshop manual for the mentioned DTC. This is for 2010+ Taurus but its likely that the strategy is the same:

The PCM monitors the generator output via the generator monitor (GENMON) circuit. The PCM uses the generator command (GENCOM) circuit to command the generator to either increase or decrease output. If the GENCOM circuit (generator control circuit) or the "A" sense circuit are open or shorted to ground, the PCM will not be able to control the generator output. When the engine speed is greater than 2,000 rpm, the generator defaults to a steady voltage output of 13.5 volts and the PCM sends a request to the IPC to illuminate the charging system warning indicator. A GENCOM circuit fault can be confirmed by viewing the PCM PID generator command line fault (GENCMD_LF) (YES status indicator fault).

So if the error is present, you should increase the engine speed to 2000+ RPM and measure the output voltage. If its around 13.5V you have afault in the generator control circuit or PCM, if it is lower you have a faulty Generator.

Hope that helps!
 

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^ This car needs some FORScan love to pull that PID from the PCM.
True, I used IDS to check it on mine and its pretty straight forward. However, if the strategy is the same on the 2008, the RPM voltage test should be enough to verify if the generator or cabling/PCM is bad.
 

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Discussion Starter #10 (Edited)
Went to the dealer yesterday, alternator was replaced. At first they only checked it out for 30 mins or so and said they couldn't do anything without the issue present. I pushed the fact I could wait all day and I didn't care if they left it running the whole time or whatever. So the mechanic had his helper run it around the lot and road test it, eventually the check charging system message came up so they could do their pinpoint testing. Mechanic said it was either going to be the alternator or the wire between the alternator and pcm but needed the issue present to nail it down. I'm really glad I went back to my old place of employment and dealt with people who I've known for years. Got lucky that the mechanic who was doing the repair was someone I knew back when I worked there and he remembered me after speaking with him for about 10 mins about the car.

 

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Discussion Starter #12
How much are Alternators going for these days? Glad they did the secondary testing of the battery......Even better at no charge.
I would guess if it's Motorcraft one probably $250-350 ballpark range, depending on if you buy it online or get it from the dealer. I wasn't told whether the one installed on my car was New or Reman. The part number is 8G1Z10346A which when searched didn't really tell me anything about item condition.

I'm really surprised for as long as it did all the times it was charging 11.x volts I never needed to get a jump start. I did at one point recharge the battery because I was going to test the cells.

So far I've made 7 trips ranging from 10 mins to 50 mins, no check charging system message. :)
 

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About three weeks ago while driving home at night out of the blue the battery light came on and check charging system warning message displayed. Looked at my radar detector which I have displaying volts and was reading 12.1. Normal voltage for the car is 13.8-14.1 at idle with no load or heavy load. Was about 15 mins from home so I turned all accessories off besides headlights. Let the vehicle sit for a few days and started it up, no problems. Drove it for two days and the same issues came back up but only stayed on for 4-5 mins then everything went back to normal. It did this several times more over the next week, then had another two day stretch with no problem.

Car has 134k miles on it so I decided to start with a few simple things first before taking it to the dealership (has basic ESP warranty), replaced the power steering and serpentine belt along with the tensioner. Made no difference as the charging at times seemed low for normal 13.4 but I know that's still in spec. New Ford battery was installed in April of this year so I knew the battery was good (I tested it anyways), load tested the alternator and it was good.

The check charging system message came on again but it was going on and off multiple times the last 30 mins of my drive. After that episode I decided to take it to the dealership. Dropped it off this morning and service writer just called me and said that there is an issue with the gauge cluster and my brake lights were acting up. I asked him "do those things have anything to do with the check charging system message and volts dropping to 12 so randomly?" He said no and then told me it would be $860.13 to replace the gauge cluster, reprogram the computer and keys. I said no, that's okay. I knew it wouldn't have an episode while it was there because it was so random when it happened while I was driving it.

95% of the time I enjoy driving this car cause it rides smooth, comfortable and nice and quiet compared to my other vehicle but I guess it knows it's paid off so it wants to act up. Battery & alternator are good, all the pullies are good, checked/cleaned every plug connector I could find as well.

Anyone else have the check charging system issue on their 2008-2009?

If your battery light is on, and it's not the alternator or the battery, And you have also checked the alternator fuse under the hood,
215685
Then you will have to go through these steps. It's either a break in an orange/blue wire coming from the connector that connects to the alternator regulator, which runs to the ECM, or you need a new ECM. Mine was the ECM. Good Luck!
 
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