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Discussion Starter · #1 ·
I started a thread about two weeks ago regarding my cars voltage problem, my car (Ford Focus ST 2015) had battery light on, and voltage was low as well, check engine lit up, battery light was turning on and off occasionally, then it stuck there for few days, and then completely disappeared for another 4 days, and voltage was around 15v so too high. I really wasn’t testing my luck, since my thread did not get a lot of response, I contacted my brothers shop, where they said that the alternator went bad 99%. I took it there and they have replaced the alternator, I picked it up, voltage still 15v even after some time driving, occasionally dropping to 14.9v and raising to 15.1v. No more battery light but check is on again. Codes P0054 and U042E.
This is very frustrating and I have 230 mile trip in a week. So to sum everything up, if alternator is not an issue, what can cause it then?
 

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I believe I remember reading AGS delete can cause weird electrical issues because canbus communication?
But I think that was often the voltage light on even tho no issue. Not voltage high.

Did you go through all this already?
Key not recognized, vehicle won't start...
 

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You Could have simply replied to your other thread from 9 days ago instead of making another one.

Did you ever check the AGS fuse? In your other thread, you said the connector was hanging. Well thats really bad if you live in an area with inclimate weather. Corrosion buildup in the electrical connector could short circuit and cause the fuse to pop.
 

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If the alternator loses LIN BUS communication is doesn't know what to do. It will default to 15 VDC output. You need to really inspect all wiring and connectors, especially the AGS connector (regardless if you have them installed) for damage / water intrusion.
 

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Discussion Starter · #5 ·
If the alternator loses LIN BUS communication is doesn't know what to do. It will default to 15 VDC output. You need to really inspect all wiring and connectors, especially the AGS connector (regardless if you have them installed) for damage / water intrusion.
I see, I will surely recheck the wiring, shortly before the issue occurred, there was a slight snow storm in Chicago, right when I was driving home from work, I was on summer semislicks (i got caught off guard with that snow), that AGS is literally hanging down into hole in undertray, and I did have and odd hole in my fender liner (which I've replaced since), AGS might've caused it, but now I track my battery with COBB, and it gives me different voltage, on very startup its around 15.2, then drops to 14,9-15v, I'm not sure if you mean that it should be 15v at all times or you mean that it would show around 15v. Also I've read that my old CEL's might just come back, it makes sense since yesterday it threw a P0141 code (O2 sensor) and I had that issue back in the day, when my AFR wasn't reading, now my AFR is fine and reading but the code still came up.
 

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Read through the provided link on post #2. It covers a lot of this.

Over voltage conditions can be difficult on certain components. I see from your mod list your running a catless DP. The P0141 is for the Bank 1 Sensor 2 (rear narrow band O2). The heating element is possibly shot in that sensor. It shouldn't effect the Wideband sensors output. Double check the wiring for damage or abrasion.

J
 

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Discussion Starter · #7 ·
You Could have simply replied to your other thread from 9 days ago instead of making another one.

Did you ever check the AGS fuse? In your other thread, you said the connector was hanging. Well thats really bad if you live in an area with inclimate weather. Corrosion buildup in the electrical connector could short circuit and cause the fuse to pop.
Read through the provided link on post #2. It covers a lot of this.

Over voltage conditions can be difficult on certain components. I see from your mod list your running a catless DP. The P0141 is for the Bank 1 Sensor 2 (rear narrow band O2). The heating element is possibly shot in that sensor. It shouldn't effect the Wideband sensors output. Double check the wiring for damage or abrasion.

J
I did check the fuse when it happened originally, it was fine, I will recheck it once again. I had a concern about it being the AGS wire hanging down during snow, but I got told that it wouldn't affect my car in such way. I will make sure to check both the wiring and fuse, and I will get back you.
Thanks a lot for help!
 

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Discussion Starter · #8 ·
Hi guys, so AGS cord is all messed up, coroted and green, how do I approach it to fix it? Battery voltage seems to be 13.9v when checked directly from alternator and battery, but cobb shows around 15v, check engines keep coming up after deleting them.
 

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You can either replace the pigtail for the AGS or delete it entirely and have a tuner turn off the DTC for it. Your will need to cut off the damaged connector regardless. If the LIN BUS wire is shorted to power or ground it will prevent the other things from communicating on that wire.

You could always try this.
How to clean heavily corroded electrical connectors.

Following the directions in the post disconnect the battery and soak the connector in the vinegar & salt solution for about 10 minutes. Clean with a plastic brush and dip in the Water & Baking Soda solution to neutralise any remaining vinegar.

But again if it's to bad it may need replaced or cut and capped off.
 

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Discussion Starter · #10 ·
You can either replace the pigtail for the AGS or delete it entirely and have a tuner turn off the DTC for it. Your will need to cut off the damaged connector regardless. If the LIN BUS wire is shorted to power or ground it will prevent the other things from communicating on that wire.

You could always try this.
How to clean heavily corroded electrical connectors.

Following the directions in the post disconnect the battery and soak the connector in the vinegar & salt solution for about 10 minutes. Clean with a plastic brush and dip in the Water & Baking Soda solution to neutralise any remaining vinegar.

But again if it's to bad it may need replaced or cut and capped off.
I've cut the wire, and capped it off, after that procedure we did "Battery optimization" after what my car was at 13.6V for the day, car sat outside for the night and it was cold (13*), after I've started the car I saw that it started at 15.3V after what dropped to 15V all the way to my work (15 min drive). Is the voltage normal now? Because there's a lot of opinions on this, and I keep hearing different things from each side, so I'd be most confident if you could tell me.
Thank you.
 
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