2020 Mustang GT ABS Problems

BLG20GT

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Jul 31, 2020
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Hey guys, I'm new to this site. I own a 2020 Mustang GT and I have been through the ringer with this car. I bought the car brand new and have had some bad luck with this car. After 2 days of owning it, my transmission goes out. I have warranty on the car so they paid for a new one. I send it to the dealership to get fixed and my car sits there a week. The day I go to pick up my car I hear that one of the new guys broke one of the bell housing bolt holes on the block of the car. So they have to replace my engine. After 2 weeks of getting my engine replaced they finally finish and I get my car back. After a little over 1,000 miles all my lights turn on. ABS, Steering assist failure, Traction control, E-brake light, Heel assist start, passenger airbag off, Turn signals don't work, bright lights don't work, windshield wipers don't work and all of the controls on my steering wheel don't work. I have no clue of the problem and I will be taking the car to the dealership Monday to take a look at it. If anyone could help me on how to get all this to go away or may know of where the problem might be i would appreciate it. I have removed the negative battery post and it still shows all these lights. I had the dealership reset all of it with a computer and it goes away for about a day. This is my only car to drive so i'm not sure what to do. If any of you could help thank you. It's supposed to rain tomorrow and it's hard to drive in the rain when the wipers don't work.Below are the pictures of the lights and a picture of the broken piece off the block.
 

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90sickfox

Wasn't a pretty sight...and I've got big hands
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Sounds like they screwed up a ground somewhere...or that new guy screwed something else up too. With the dealership scanner it shouldn't be hard to find. Your issue seems to be a couple different modules so I doubt it's a module issue...or sensor issue. More than likely a ground issue or short causing the modules to shut down
 
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MustangIIMatt

Easy there, this ain't a dating site.
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Sounds like they screwed up a ground somewhere...or that new guy screwed something else up too. With the dealership scanner it shouldn't be hard to find. Your issue seems to be a couple different modules so I doubt it's a module issue...or sensor issue. More than likely a ground issue or short causing the modules to shut down
This or they pinched a CAN-BUS line somewhere.

I've seen these symptoms caused by a bent pin on the bulkhead connector of an F150's transmission causing a short on the CAN-BUS that registered as everything BUT an issue at the transmission. (THAT was fun to track down...) Raise hell and have them give it to the shop foreman or their best electrical guy, a short in CAN-BUS is not something you want in the hands of your average parts-swapper.
 
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MustangIIMatt

Easy there, this ain't a dating site.
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Sometimes I read the S550 forums. New cars have some crazy problems. Dealers must have ten cars at a time under warranty.
Fixt it for you.

It's every brand. The Asian makes (other than Nissan/Mitsubishi) have the least problems, but they all have weird issues that leave industry veterans like me scratching our heads.

My favorite recent one was a towed in car with 131 fault codes... It needed a software update for the BCM to fix it. 200 miles on the car. That was fun to figure out.

Also fun is BMW 7-series that come in with a parasitic draw that's impossible to pinpoint the old fashioned way because it only draws enough to keep the modules from going to sleep (we're talking milliamps here), not enough to register on the scope when pulling fuses. Most of the time it ends up being a bad door handle. No, I'm not kidding.

I've run into similar issues on newer Fords. I had a Fusion that the rear window on the passenger side wouldn't work because the passenger side front door module was bad. I had an S197 Mustang with a short at the fuel pump harness under the seat. Then there was the Explorer airbag systems I was always diagnosing and repairing.

Don't get me started on GM and Stellantis.
 
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