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Discussion Starter · #1 ·
2006 Ford Taurus
I get an intermittent CHECK CHARGING SYSTEM message. The message seems to be random. I can drive to the store (15 min) and get no message and then get 3 messages on the ride home. It will beep and come on for varying lenghts of time (sometimes for a few seconds and sometimes longer). I don't recall it ever staying on for more than a minute.

Here is what I've done so far:
1) Checked DTCs - none recorded.
2) Checked battery voltage with the Instrument Cluster voltage meter and the readings seemed to be acceptable (never higher than 14.6 and never lower than 13.9). The readings were taken both when the error message was on and when it was off. Checked the Instrument Cluster voltage meter against another meter and results were similar.
3) Checked output of alternator with all accessories on and battery is still charging (around 14 volts). Turning all accessories on will not cause the error message.
4) The only clue that I have found is in the Engineering Test Mode of the Instrument Cluster. In the Engineering Test Mode there is a CHARGE STATE menu item. The value for this is 20$ when the message is off and it changes to $24 when the message is on.

I have searched and haven't found any references to this CHARGE STATE menu item and what the codes mean. Does anyone have any suggestions for troubleshooting / repairing this issue?
CS24.jpg cs20.jpg
 

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How many miles on the car? If it is around 150K miles it could be the alternator brushes are worn and at high rpms they intermittently lose contact with the slip rings. Also check the small wire connector on the alternator and remove it and reseat it a few times.
 

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Discussion Starter · #3 ·
Car has 60k miles (was mother-in-laws and she rarely drove). I have the service manual and have been looking at wiring diagrams. I was planning on cleaning that connection and a couple of others. Will do tomorrow.
 

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Car has 60k miles (was mother-in-laws and she rarely drove). I have the service manual and have been looking at wiring diagrams. I was planning on cleaning that connection and a couple of others. Will do tomorrow.
I would invest few bucks on one of these, then see what is really going on. Pic is the delux with charging ports for USB. ~$12 on the internet.
Or spend a bit more on "carchip" which can record and download to a computer and show charts of volts or a list of other things. I used mine and found my '03 Sable was serious overcharging. Up to 15.8V from time to time and likely explains cluster bulbs burned out and console bulbs out. Used car and I replaced the Alt. Bad regulator.
-chart-
 

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Discussion Starter · #5 ·
I would invest few bucks on one of these, then see what is really going on. Pic is the delux with charging ports for USB. ~$12 on the internet.
I bought a OBDLink® MX+ Bluetooth and have monitored voltage through OBDLink and ForScan apps. There are no abnormal voltage readings whether the error message is on or off. At least one of this apps (maybe both, I can't remember) gives a graphical display of voltage vs. time and I tested with it multiple times.
 

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Check all grounds. They can be bad and show no signs. Ford bolts eyelets over paint. I do, key on engine off, blower max, HL on. Measure volts drop, battery negative post to the fender. Max allowed 0.1V = 100 mv.
Engine running, same blower and HL, measure volts engine block to firewall. Same limits. See pic, this was causing unstable idle. Secondary ground to fender easy fix.
-chart-
 

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I have a 2007 Taurus and I have the same issue with a P0622 - charging system fault (no check engine light). I have a OBD reader and a volt meter connected directly to the battery with a switch that can switch it over to on with accessories. I have tried all the ford manual troubleshooting testing with a multimeter and all have passed. The voltage shows around 14.0 to 14.6 depending on temperature outside,seems to be higher when its really cold out (northern MN).

I recently got a new motorcraft battery as my old one was showing its age, and still have charging issues. I purchased this car with some information on previous repairs and the alternator is listed as being replaced, which might not be a motorcraft brand and I have read these cars are picky on alternators.

When I am driving with my car recording FORSCAN OBD data I have concluded that it throws this error message when the voltage from the alternator is more than the desired voltage called for by the computer. Reviewing the data collected during my drives the charging seems to be normal with maybe a few seconds of being over the desired voltage by no more than .1 to .2, max voltage around 14.8 for just a few seconds which seems to trigger the dash warning and it stays up for a random amount of time.

I have cleaned up all my grounds and did the BIG 3 by adding thick wire used for welding and didn't help. I have had this issue for over a year now and starting to think its the alternator. At least my battery is being charged and the fluid is not boiling off from overcharging. I have noticed GENCOM and GENMON are doing some odd things when recording my drive with FORSCAN and OBDLINK MX+. GENCOM is almost always at 0% the entire drive. GENMON seems to flat line to 0% when the error happens and starts working again when the error goes away. Any help or ideas would be great!


ForscanCharge1.JPG
ForscanCharge2.JPG
ForscanCharge3.JPG
 

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I have a 2007 Taurus and I have the same issue with a P0622 - charging system fault (no check engine light).
...
I purchased this car with some information on previous repairs and the alternator is listed as being replaced, which might not be a motorcraft brand and I have read these cars are picky on alternators.
...
I have had this issue for over a year now and starting to think its the alternator.
It might very well be the alternator. Its connector has three pins:

Alternator-Remy.jpg

I think the middle one (called FR) is to report the status to the PCM. In my 2000 Vulcan this pin is not connected at all. In your 2007 model it probably is. And so an alternator that is guaranteed to fit my 2000 Vulcan does not need to support that middle pin because it will not be used anyway. If you have such an alternator you might have a problem. But it might be enough to change the regulator.
 

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'02 and later use this system where the middle wire is a signal 0-5V to manage output.
Before that center wire was to do the red light for charging.
'02 and later use the PCM to signal the red light.
-chart-
 

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I think that is the confusing part. In my 2000 Vulcan the middle pin is not connected, also not to the Battery light in the instrument cluster. That light is attached to the pin marked L/IG with a LightGreen/Red wire. I assume that pin carries 12 V when the alternator works, since the other side of that Battery light is attached to 12 V, so the light goes on when the alternator doesn't work.

So in later models that same pin (circuit 1181 in your picture) first goes to pin 20 of the PCM and then through the old LightGreen/Red wire to the instrument cluster. The middle pin (circuit 3990) indeed now goes to pin 45 of the PCM which is called "Sensor signal, Generator, common". Sounds like an input to me. I don't think the PCM is controlling the alternator, it is just monitoring. In the problems described in this thread the PCM seems not very happy with that signal though.
 

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For completeness: I was wondering how the regulator knows it needs to power the rotor of the alternator. After all the A+ pin is directly attached to the battery through a 30 A fuse so that line is not switched. But that is where the resister in the instrument panel gets in. The other side of the red battery light is Hot in Run or Start according to the Haynes manual. So whether there is a battery light or not, the regulator senses 12 V there and does its thing. And this also clarifies the L/IG marking: it means Light/Ignition.
 

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Here is a diagram for a 2007, its almost the same with minor differences.

218592



Operation of the charging system.
218594



PCM Pinout
218600



Symptoms and Troubleshooting
218593


---- Pinpoint Testing Procedures ---
Testing A.pdf
Testing B.pdf
Testing C.pdf
Testing D.pdf
Testing E.pdf


I have tried all the troubleshooting and everything passed. It would be nice to solve, but its very intermittent and seems random. My battery stays charged and does not seem to be getting overcharged so I might just have to live with it instead of wasting more time on this issue.

Maybe these pictures and PDF might help someone with their problem, I wish you luck!
 

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It could always be a little corrosion or less that optimum contact of the instrument cluster connector. Maybe if the light is on you can smack the dash to see if the instrument cluster needs to be pulled and reset into connector. In the troubleshooting guide it does state if the light is intermittent the cluster needs to be replaced.
 

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I have cleaned all the contacts including the grounds, checked all the pins and it didn't seem to fix it. I still think its the alternator, I have read a few times these cars are picky about the alternators and can cause this issue with off brand ones. The instrument cluster works fine for everything else, I don't think its affecting the charging system in the way its acting and also messing up the GENMON and GENCOM signal on the alternator.

Looking at the OBD data GENMON and GENCOM don't seem to be working correctly. GENMON flatlines 30 seconds before the error happens and starts working again right when the error goes away. GENCOM seems to be flat lines almost the entire time.

The alternator was replaced on my vehicle before I purchased it, its probably a off brand one and not a motorcraft.
 

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I have cleaned all the contacts including the grounds, checked all the pins and it didn't seem to fix it. I still think its the alternator, I have read a few times these cars are picky about the alternators and can cause this issue with off brand ones. The instrument cluster works fine for everything else, I don't think its affecting the charging system in the way its acting and also messing up the GENMON and GENCOM signal on the alternator.

Looking at the OBD data GENMON and GENCOM don't seem to be working correctly. GENMON flatlines 30 seconds before the error happens and starts working again right when the error goes away. GENCOM seems to be flat lines almost the entire time.

The alternator was replaced on my vehicle before I purchased it, its probably a off brand one and not a motorcraft.
So you are not the original poster! You high jacked the post. You have the same issue? I wouldn't trust an remanufactured alternator. Brushes and slip-
IMG_9570.JPG
ring could be bad. IMG_9570.JPG IMG_9654.JPG IMG_9570.JPG
 

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Looking at the OBD data GENMON and GENCOM don't seem to be working correctly. GENMON flatlines 30 seconds before the error happens and starts working again right when the error goes away. GENCOM seems to be flat lines almost the entire time.
Of course the PCM reacts to a flatfined GENMON by raising the Generator Fault Indicator Lamp and visa versa.
But it seems the GENMON signal is wrong because the module voltages stay around 14.5 V. Where is that supposed to come from when the alternator doesn't produce output?
Might indeed be a bad a contact. Did you already try to take the regulator out and put it back in?
I find it hard to believe the regulator works properly (see the module voltages) but doesn't raise the L/I signal (analog or PWM) accordingly to turn off the Battery light (directly or indirectly through the PCM).
 

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I guess you could say I hijacked the thread, but I tried posting information and troubleshooting in here so he and others could take advantage of it. And yes I do have a very similar issue as OP but in a 2007.

So you were right. The terminals of the 2007 models are
and make clearer that the middle pin really is communication with the PCM, though not in which direction.
From the above Operation page i posted, it says the communication is a 2 way signal.

But it seems the GENMON signal is wrong because the module voltages stay around 14.5 V. Where is that supposed to come from when the alternator doesn't produce output?
When the GENMON signal goes to zero, it usually happens after the voltage goes above the desired amount, even when it was just for a second or 2. The alternator never stop putting out voltage, its almost always 14-14.5 when I am driving.

From what I have read it seems the alternator has a built in regulator and you have to replace the entire unit
 

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I guess you could say I hijacked the thread, but I tried posting information and troubleshooting in here so he and others could take advantage of it. And yes I do have a very similar issue as OP but in a 2007.



From the above Operation page i posted, it says the communication is a 2 way signal.



When the GENMON signal goes to zero, it usually happens after the voltage goes above the desired amount, even when it was just for a second or 2. The alternator never stop putting out voltage, its almost always 14-14.5 when I am driving.

From what I have read it seems the alternator has a built in regulator and you have to replace the entire unit
Pic of internal regs from DOHC engines, left one rebuilt and the brush leads are too short but it would work for a while. Other two OE brushes and easy to see they have full length leads.
Right one V-8 use with two wire and some are to never be reused as they fail. Had that on Lin. Twice. Good ones have a ground on one screw, bad ones do not have a ground.
Left two, one for PCM control (gray) as in '01 and earlier, Middle one for '02 and later (white) for PCM managed cars. All 3 from the JY. Easy to remove.
As a sidebar: my Buick Lucerne ('11) they put the regulator on the firewall. Electronics do not like hear and vibration. Years ago many if not most makers put the reg inside the Alt. Nothing wrong with having it in a cooler and less harsh envournment. My op.
-chart-
 

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Pic of internal regs from DOHC engines, left one rebuilt and the brush leads are too short but it would work for a while. Other two OE brushes and easy to see they have full length leads.
Right one V-8 use with two wire and some are to never be reused as they fail. Had that on Lin. Twice. Good ones have a ground on one screw, bad ones do not have a ground.
Left two, one for PCM control (gray) as in '01 and earlier, Middle one for '02 and later (white) for PCM managed cars. All 3 from the JY. Easy to remove.
As a sidebar: my Buick Lucerne ('11) they put the regulator on the firewall. Electronics do not like hear and vibration. Years ago many if not most makers put the reg inside the Alt. Nothing wrong with having it in a cooler and less harsh envournment. My op.
-chart-
Mix up on text. Gray is NON PCM '01 and earlier.
-chart-
 
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