08 GT DTC code P0622
09-02-2012, 08:04 PM
#1
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08 GT DTC code P0622
OK so I have fault code 0622, Generator field circuit fault. I have a new battery and tried replacing the alternator with one from Oreilly's and Advanced Auto. Both of the alternators I have bought have failed when tested. When I put the alternator in it will run for a little bit and then I get a "Check charging system" message. A guy from a local performance shop said to order a PA from AM, which I did today. He also said it is not unusual for the Major chains to stock faulty rebuilt alternators.
I have checked all the wiring, replaced all grounds, and check the alternator cable. They are all good. I'm just wondering if anybody else has ever had this problem so I can feel a little better about all this BS I've been through. ANy advice would be greatly appreciated. Also, do I need to replace wires going to the PCM. I can not locate one of the Yellow wires at the PCM. Please help
I have checked all the wiring, replaced all grounds, and check the alternator cable. They are all good. I'm just wondering if anybody else has ever had this problem so I can feel a little better about all this BS I've been through. ANy advice would be greatly appreciated. Also, do I need to replace wires going to the PCM. I can not locate one of the Yellow wires at the PCM. Please help
09-02-2012, 09:35 PM
#2
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Wait for Wayne613 on this one. PA is the way to go and I would suggested going to heavier alt cables if you haven't already. You can also make a ground kit or buy the Steeda ground kit for extra grounding.
09-02-2012, 11:43 PM
#3
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My ears are ringing for some reason...
I've never actually had this happen. Mine straight up died without any DTCs as the rectifier board still had like 1 diode working when I yanked it, so it didn't re-charge jack, just left me stranded, just good enough to keep things going after a jump then leave me to start it again flintstones style later.
I am using a PA performance 200A, but the rebuilt ones should have worked fine. Unless they're just receiving them, not checking squat and just slapping a new regulator in. Which is extremely doubtful. If you get a replacement that is greater than the 130A max, then you'll need to upgrade the wiring as JCON already stated.
Not to insult the speedshop guy, but he likely simply didn't want to walk you through something he wasn't going to be paid for anyhow. Most of the time the rebuilt ones are fine. Getting a single bad one, ok, getting another one that still doesn't work? Yeah, no... I won't even ask why you didn't just exchange to the first shop.
You don't mention what you did to test exactly, nor any specific symptoms:
Voltage go up at all when the engine is on?
If there is no change, did you check continuity on alternator hot line since it has a fusible link?
Higher when you gun it?
steady 13.5v after 4 seconds at WOT?
http://iihs.net/fsm/?dir=361&viewfil...g%20System.pdf (see below, and go to page 4 "symptom chart" for your specific issue to troubleshoot properly):
Absolute first thing, verify (BEC) fuse 43 (10A), then check the wiring harness for corrosion (not the B+ line) and/or cancel your order, as I doubt the replacement is the issue, even if it is, exchange it, and use the saved money for a decent mod. Or hell, give it to me, I wish I had that much money to spend on something.
Then check the PCM pins/harness (bent, corrosion on pin or harness adapter, check continuity from each harness pin to connector).
PA performance is a good one to get, but just to be clear, you can buy rebuilt ones off ebay that are just as good if you look hard enough (Search on "FORD 6G alternator"). I got a second alternator (240A this time) for near half the price there recently, and I yanked it apart and used it briefly to verify. Not to mention, if you're slightly handy, and can solder ok, you can rebuild it yourself quite easily for <$40.
http://iihs.net/fsm/?dir=39&viewfile...%20Mustang.pdf (E5, Engine/wiring harness pin 5 is what you're after I believe, "GENMN", generator monitor line).
E-5 = pin 1 on harness (Yellow)
E-13 = pin 2 on harness (Yellow with light blue stripe)
pin 3 on harness (Orange with light blue stripe) should read as the same voltage as the battery. Sensor is internal to PCM, but uses pin B-36(Body pin 36) for it I think. Easy enough to find with continuity test (assuming no break/corrosion issue), either pin 35, 36, or 45 all on body harness. I mention this as if the test fails, and doesn't read near the battery's voltage, then either the line has an issue or the PCM does, to find out you'll have to trace that wire back and test it (goes through BEC fuse 43, so replace this first even if you don't think it's broken).
.
http://www.ebay.com/itm/Ford-6G-Seri...-/330787255111 (in case you find the harness at the alt is bad)
From http://www.fordtechservice.dealercon...torcatalog.pdf (part WPT-118), in case you can find it elsewhere cheaper...
I've never actually had this happen. Mine straight up died without any DTCs as the rectifier board still had like 1 diode working when I yanked it, so it didn't re-charge jack, just left me stranded, just good enough to keep things going after a jump then leave me to start it again flintstones style later.
I am using a PA performance 200A, but the rebuilt ones should have worked fine. Unless they're just receiving them, not checking squat and just slapping a new regulator in. Which is extremely doubtful. If you get a replacement that is greater than the 130A max, then you'll need to upgrade the wiring as JCON already stated.
Not to insult the speedshop guy, but he likely simply didn't want to walk you through something he wasn't going to be paid for anyhow. Most of the time the rebuilt ones are fine. Getting a single bad one, ok, getting another one that still doesn't work? Yeah, no... I won't even ask why you didn't just exchange to the first shop.
You don't mention what you did to test exactly, nor any specific symptoms:
Voltage go up at all when the engine is on?
If there is no change, did you check continuity on alternator hot line since it has a fusible link?
Higher when you gun it?
steady 13.5v after 4 seconds at WOT?
http://iihs.net/fsm/?dir=361&viewfil...g%20System.pdf (see below, and go to page 4 "symptom chart" for your specific issue to troubleshoot properly):
NOTE: DTC P0622 can be set by the loss of the
communication lines between the generator and the
PCM. The charging system warning indicator then
illuminates until the engine is operated at greater
than 4,500 rpm (approximately wide open throttle
[WOT]) for a minimum of 3 seconds. At this time,
the generator self-excites. The charging system
warning indicator remains illuminated, and the
generator operates in a default mode (approximately
13.5 volts) until the engine is turned off.
communication lines between the generator and the
PCM. The charging system warning indicator then
illuminates until the engine is operated at greater
than 4,500 rpm (approximately wide open throttle
[WOT]) for a minimum of 3 seconds. At this time,
the generator self-excites. The charging system
warning indicator remains illuminated, and the
generator operates in a default mode (approximately
13.5 volts) until the engine is turned off.
Then check the PCM pins/harness (bent, corrosion on pin or harness adapter, check continuity from each harness pin to connector).
PA performance is a good one to get, but just to be clear, you can buy rebuilt ones off ebay that are just as good if you look hard enough (Search on "FORD 6G alternator"). I got a second alternator (240A this time) for near half the price there recently, and I yanked it apart and used it briefly to verify. Not to mention, if you're slightly handy, and can solder ok, you can rebuild it yourself quite easily for <$40.
http://iihs.net/fsm/?dir=39&viewfile...%20Mustang.pdf (E5, Engine/wiring harness pin 5 is what you're after I believe, "GENMN", generator monitor line).
E-5 = pin 1 on harness (Yellow)
E-13 = pin 2 on harness (Yellow with light blue stripe)
pin 3 on harness (Orange with light blue stripe) should read as the same voltage as the battery. Sensor is internal to PCM, but uses pin B-36(Body pin 36) for it I think. Easy enough to find with continuity test (assuming no break/corrosion issue), either pin 35, 36, or 45 all on body harness. I mention this as if the test fails, and doesn't read near the battery's voltage, then either the line has an issue or the PCM does, to find out you'll have to trace that wire back and test it (goes through BEC fuse 43, so replace this first even if you don't think it's broken).
.
http://www.ebay.com/itm/Ford-6G-Seri...-/330787255111 (in case you find the harness at the alt is bad)
From http://www.fordtechservice.dealercon...torcatalog.pdf (part WPT-118), in case you can find it elsewhere cheaper...
Last edited by wayne613; 09-03-2012 at 02:08 AM.
09-03-2012, 08:22 AM
#4
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Join Date: Jun 2012
Location: IN
Posts: 69
Thanks Wayne613 for the help. So far what I've done is
-Checked alternator cable continuity and fusible link
-Rang out B+ wire on alternator wiring (OK)
-Checked the two yellow wires for short / grounds
Here is the problem. I can't locate one of the yellow wires on alternator plug.
-I've changed the battery cables. They were old and needed it.
-Checked alternator cable continuity and fusible link
-Rang out B+ wire on alternator wiring (OK)
-Checked the two yellow wires for short / grounds
Here is the problem. I can't locate one of the yellow wires on alternator plug.
-I've changed the battery cables. They were old and needed it.
09-03-2012, 08:38 AM
#5
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Join Date: Dec 2010
Location: Gallifrey
Posts: 1,596
So gist being, main wiring is the only thing really verifiable at present, no other troubleshooting aside from making sure the 2 alternator communication specific lines weren't grounded or shorted together. Same gauge wiring as before..
Second half of my quite long first reply has what you're looking for, and what you should check.
Second half of my quite long first reply has what you're looking for, and what you should check.
Last edited by wayne613; 09-03-2012 at 08:40 AM.
09-03-2012, 09:26 AM
#6
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Ok. I checked continuity from alternator plug to PCM plug and here is what I have :
-OR/LB : +11.8 VDC WRT grnd
-YW : .4 ohm
-YW/LB : There is no pin in position according to diagram. I have the plug print and where it says to check continuity to PCM there is NO female receptacle on the PCM plug. I think maybe it got pulled out. Checked WRT ground and it is OPEN so I know its not grounded. Is it possible the pin got pulled out on the PCM plug ?
Thanks for the help.
-OR/LB : +11.8 VDC WRT grnd
-YW : .4 ohm
-YW/LB : There is no pin in position according to diagram. I have the plug print and where it says to check continuity to PCM there is NO female receptacle on the PCM plug. I think maybe it got pulled out. Checked WRT ground and it is OPEN so I know its not grounded. Is it possible the pin got pulled out on the PCM plug ?
Thanks for the help.
09-03-2012, 10:02 AM
#7
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Join Date: Dec 2010
Location: Gallifrey
Posts: 1,596
The diagram could be wrong, wouldn't be the first time. You're talking about pinpoint test B4, yes?
Can you not wipe-down the wires and verify the color matches? If it does, use a pin(or super-small screwdriver) to tap into there if the pin is missing, then check for continuity again.
If it got bent, broken, or actually rusted into the harness and yanked out, that would explain it, but it's not that likely unless someone's been fiddling with it as they're fairly air-tight.
Can you not wipe-down the wires and verify the color matches? If it does, use a pin(or super-small screwdriver) to tap into there if the pin is missing, then check for continuity again.
If it got bent, broken, or actually rusted into the harness and yanked out, that would explain it, but it's not that likely unless someone's been fiddling with it as they're fairly air-tight.
Last edited by wayne613; 09-03-2012 at 10:15 AM.
09-03-2012, 10:09 AM
#8
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Join Date: Jun 2012
Location: IN
Posts: 69
I have the PCM plug flex stripped back and I am trying to locate the YW/LB wire. I can not locate it by ringing it out, so I will manually pull the wire from the harness to see if I can locate it. Every diagram I have puts the YW/LB in the same pin position as the diagrams you posted. Thats why Im a little confused, wires don't just disappear.