[NukerST]

So the battery light has been coming on. I have read through everything i could find on this subject. The anxiety-port says I'm charging anywhere from 14.5 to 15. When i hold the OK button to get into test mode, it says battery voltage is 11.9 to 12. i did find corrosion on the battery teriminals, but changed both + and - cables to new Ford OEM cables and replaced the battery to a Duralast Platinum. Which did turn the light off for a couple days, but now it is back on! i have reset the battery sensor, which is new, with the turn on car, turn on headlights, flash brights 5 times, and 3 brake pushs.. and light comes back on. checked all fuses, they are good. but i get the code u012d. Lost Communication With Generator Control Module .. Any ideas??

 

[TurboGT]

Did you happen to remove the AGS fuse for any reason?

 

[NukerST]

Did you happen to remove the AGS fuse for any reason?

just to check it.. was good and put it back in... i removed the AGS about 4 months ago. no ags.. but fuse is still there.. when i removed the AGS, i completely removed the AGS with motor, taped off plug and zip tied out of way.. i did not remove the motor from AGS and zip tie in car. Battery light never came on since AGS removal. battery light has been on last week or so.

 

[TurboGT]

So we have to figure out why the PCM (read by the accessport) shows proper voltage bur the IPC shows low voltage. When this variance exists, what is the battery voltage at the battery terminals, checked with a voltmeter?

Do you have access to forscan, or some other scanner that can retrieve data from all modules?

 

[NukerST]

So we have to figure out why the PCM (read by the accessport) shows proper voltage bur the IPC shows low voltage. When this variance exists, what is the battery voltage at the battery terminals, checked with a voltmeter?

Do you have access to forscan, or some other scanner that can retrieve data from all modules?

Yes I have Forscan.... I will read with voltmeter in morning.

 

[SSgtjrobertson]

Key not recognized, vehicle won't start...

*Updated to add mention of the AGS causing a communications problem with the alternator and battery light. 11/28/2020 05/27/2021 - BMS manual reset procedure added courtesy of @ddfred 07/12/2021 Ford part number for fuse added 07/18/2021 Added full location, description, and Ford part...

www.focusst.org

 

[NukerST]

Key not recognized, vehicle won't start...

*Updated to add mention of the AGS causing a communications problem with the alternator and battery light. 11/28/2020 05/27/2021 - BMS manual reset procedure added courtesy of @ddfred 07/12/2021 Ford part number for fuse added 07/18/2021 Added full location, description, and Ford part...

www.focusst.org

lol.. i have went through that post with a fine tooth comb over the past 2 weeks. i have done pretty much everything except for the one with the bus scope... I dont have one. Other than that, I have tried everything else... The only thing i found was the corrosion on the + terminal, none on - terminal. And it wasnt as bad as some i have seen here. i would say moderate corrosion, not excessive or ridiculous. With that, i changed the Battery to new, replaced both + and - cables. light went off for a few days, but is now back on.. the car is obviously charging as i have driven now with the battery light on over 2 weeks. Has never went dead. I even used forscan and enabled global windows and disabled double honk with the battery light illuminated. its driving me nuts. guess I will have to run tank to almost empty (running e30 tune), put back to stock tune, put stock cat back on and take it to ford. Still have warranty. I was hoping to not have to switch CAT to take to dealer. Was hoping maybe I missed something and someone like yourself, the electrical wizard, would bless me with the magical answer.

 

[ddfred]

All these eletrical posts lately...reminded me the battery in my truck is in need of replacing. Just checked prices and they are up about 50% since I bought a battery for the focus two years ago.

 

[NukerST]

All these eletrical posts lately...reminded me the battery in my truck is in need of replacing. Just checked prices and they are up about 50% since I bought a battery for the focus two years ago.

yeah. the Duralast platinum ran me 199.99... crazy...

 

[ddfred]

yeah. the Duralast platinum ran me 199.99... crazy...

Duralast Gold for my 2003 Ranger= 179.95
Duralast= 159.95

It wasn't that long ago premium batteries were right at 100.00

 

[Mzdrati]

So the battery light has been coming on. I have read through everything i could find on this subject. The anxiety-port says I'm charging anywhere from 14.5 to 15. When i hold the OK button to get into test mode, it says battery voltage is 11.9 to 12. i did find corrosion on the battery teriminals, but changed both + and - cables to new Ford OEM cables and replaced the battery to a Duralast Platinum. Which did turn the light off for a couple days, but now it is back on! i have reset the battery sensor, which is new, with the turn on car, turn on headlights, flash brights 5 times, and 3 brake pushs.. and light comes back on. checked all fuses, they are good. but i get the code u012d. Lost Communication With Generator Control Module .. Any ideas??

Did you ever come to a resolution with this problem? My Battery light came on on my 20 minute drive home from my night job for the first time ever (or at least that I ever noticed). What i noticed it, I pulled into a gas station, shut the car off, restarted and it was not on, but then came on a few minutes later. The car runs fine, with no noticeable effects. I parked the car for the night (inside my garage) but when I look up what the battery light means in the manual- it's called an Ignition Fault indicator or something like that. The manual states that if this light comes on while driving to have the car evaluated promptly.

The car is mostly stock- but I did just hardwire a dashcam and used F85 for switched ignition, and F88 for constant power. F85 powers several functions according to the manual, including "voltage quality monitoring". Could the fact that I'm using a fuse tap on this fuse cause this problem? I did also recently replace my battery (with the appropriate Interstate battery for this car... Group 94 or 95 IIRC). I reset the BMS as well at that time (last week). I mean- I think it's reset- the battery light flashed a few times confirming. Is there another way to know?

If I look at my Battery Voltage using my AP3- it says 10.60V (when the car is off). Checking with a voltmeter- the battery reads 12.71V

I don't think I pulled the AGS fuse (I'm not sure which one it is) but I may have. I might have to look at the open AGS connector to see if water got in there when I washed the car.

Any suggestions?

 

[SSgtjrobertson]

Did you ever come to a resolution with this problem? My Battery light came on on my 20 minute drive home from my night job for the first time ever (or at least that I ever noticed). What i noticed it, I pulled into a gas station, shut the car off, restarted and it was not on, but then came on a few minutes later. The car runs fine, with no noticeable effects. I parked the car for the night (inside my garage) but when I look up what the battery light means in the manual- it's called an Ignition Fault indicator or something like that. The manual states that if this light comes on while driving to have the car evaluated promptly.

The car is mostly stock- but I did just hardwire a dashcam and used F85 for switched ignition, and F88 for constant power. F85 powers several functions according to the manual, including "voltage quality monitoring". Could the fact that I'm using a fuse tap on this fuse cause this problem? I did also recently replace my battery (with the appropriate Interstate battery for this car... Group 94 or 95 IIRC). I reset the BMS as well at that time (last week). I mean- I think it's reset- the battery light flashed a few times confirming. Is there another way to know?

If I look at my Battery Voltage using my AP3- it says 10.60V (when the car is off). Checking with a voltmeter- the battery reads 12.71V

I don't think I pulled the AGS fuse (I'm not sure which one it is) but I may have. I might have to look at the open AGS connector to see if water got in there when I washed the car.

Any suggestions?

Check the BMS sensor for corrosion. (Connector & sensor body) Also check that the white wire leading from the red battery terminal doesn't have any corrosion as thus powers the BMS sensor.

With the vehicle at Idle measure voltage at the battery. Should be around 14 VDC.

Yes if the AGS (or alternator) connectors have moisture trapped this can also cause a battery light to trigger.

The components you added did not cause this to happen.

I believe that a 96R is the correct size battery. If you switch size or styles the PCM must be updated to reflect this change

 

[Mzdrati]

Check the BMS sensor for corrosion. (Connector & sensor body) Also check that the white wire leading from the red battery terminal doesn't have any corrosion as thus powers the BMS sensor.

With the vehicle at Idle measure voltage at the battery. Should be around 14 VDC.

Yes if the AGS (or alternator) connectors have moisture trapped this can also cause a battery light to trigger.

The components you added did not cause this to happen.

I believe that a 96R is the correct size battery. If you switch size or styles the PCM must be updated to reflect this change

Thanks so much for your response, SSgt. The car has ~15kmi on it, and the battery terminals, the BMS sensor- the whole area looked new when I changed the battery. Zero corrosion, and I took particular care to be as gentle as possible when lostening the front of the battery box and sliding the battery out of and into the battery box. I put a new Interstate: MTP-96R-1 (590 CCA) battery (Costco PN 852197) in the car maybe 10 days ago:

The only thing that I changed during the installation is that I added oil-impregnated felt washers and terminal spray as was recommended by the experienced folks here.

Should this battery work with the factory settings, or is there a change needed in Forscan?

With respect to the white BMS wire- is there a way to test it for a clean connection? I see no corrosion whatsoever.

When the engine is running, the battery shows 14.50V (when monitoring Battery V on the AP3).

For completeness- I removed the AGS system completely (per the instructions that Ford provides with their Ford Performance / mountune FMIC) and the open connector was put into a balloon and zip tied. That was a going on 2 years ago, and i have not had any problems and have not thought about it since, as there has never been a problem with it.

I did find this interesting video that might not be relevant to my issue, but may be of interest to others:

 

[SSgtjrobertson]

Thanks so much for your response, SSgt. The car has ~15kmi on it, and the battery terminals, the BMS sensor- the whole area looked new when I changed the battery. Zero corrosion, and I took particular care to be as gentle as possible when lostening the front of the battery box and sliding the battery out of and into the battery box. I put a new Interstate: MTP-96R-1 (590 CCA) battery (Costco PN 852197) in the car maybe 10 days ago:

View attachment 403825


The only thing that I changed during the installation is that I added oil-impregnated felt washers and terminal spray as was recommended by the experienced folks here.

Should this battery work with the factory settings, or is there a change needed in Forscan?

With respect to the white BMS wire- is there a way to test it for a clean connection? I see no corrosion whatsoever.

When the engine is running, the battery shows 14.50V (when monitoring Battery V on the AP3).

For completeness- I removed the AGS system completely (per the instructions that Ford provides with their Ford Performance / mountune FMIC) and the open connector was put into a balloon and zip tied. That was a going on 2 years ago, and i have not had any problems and have not thought about it since, as there has never been a problem with it.

I did find this interesting video that might not be relevant to my issue, but may be of interest to others:

Same battery I have and voltage looks good. Double check that balloon covering as that is not a long term solution. I removed the actual motor from the AGS assembly and secured it out of the way.

Felt washers will be fine. Battery terminal connections should be dry & clean. Only then after those connections are made should spray or protectant be used.

 

[Mzdrati]

I have to find that plug... Hopefully I can do it without removing the bumper. To your knowledge- is there any danger in driving the car with the battery light on (or on intermittently)? I may not be able to get to this project until next week.

The spray was applied to the terminals while everything was very clean and dry and the battery was new.

Ford Performance instructs to simply unplugging the AGS (as opposed to removing the motor and keeping it on the car) which is why I went that route. It's been that way for almost 2 years, and this is the first I've noticed the battery light on (although I have to admit- it's hidden behind the speedo needle and wasn't that obvious to me...)

Thank you again for offering your extremely valuable input.

 

[NukerST]

Check the BMS sensor for corrosion. (Connector & sensor body) Also check that the white wire leading from the red battery terminal doesn't have any corrosion as thus powers the BMS sensor.

With the vehicle at Idle measure voltage at the battery. Should be around 14 VDC.

Yes if the AGS (or alternator) connectors have moisture trapped this can also cause a battery light to trigger.

The components you added did not cause this to happen.

I believe that a 96R is the correct size battery. If you switch size or styles the PCM must be updated to reflect this change

it was the BMS sensor and corroded terminal..

 

[SSgtjrobertson]

Why so negative? (BMS corrosion related)

As I have discussed in the past (and ad nauseam) a properly functioning electrical system is extremely important to the long-term operation & performance of your ST. Traditional wear, environmental exposure or improper modifications can and will effect your ride. In the past automotive...

www.focusst.org

 

[Mzdrati]

My BMS Sensor is in what looks like new condition. Zero corrosion, no other damage. Can these just fail without any obvious reason?

 

[SSgtjrobertson]

My BMS Sensor is in what looks like new condition. Zero corrosion, no other damage. Can these just fail without any obvious reason?

You could be dealing with the early stages of a failing alternator.

 

[TurboGT]

New doesn't mean good. That's why cars carry a warranty. Ever hear of the bathtub curve?