My Mustang is Borderline Undriveable. MAJOR problems.

[15wile]

Major problem with my Mustang. It's basically undrivable at the moment. Wonder if y'all might have some insight to help me diagnose (because don't want to get bent over by a dealer if I can avoid it). 2015 Mustang GT, Manual transmission, 300A package, ~65k miles.

Problem started last Friday. Got an "Advancetrac Service" warning, then the ABS light came on, traction control was shutoff, and hill start assist shutoff. Then, over the weekend, the problem went away on its own.

Tuesday morning, the car lurches badly in first gear when I leave for work. Advancetrac warning comes again. Same thing, ABS light on, hill start assist off. No traction control.

Yesterday evening, when I hit the cruise control button - it fails, the car goes absolutely bonkers. Motor starts dogging and sputtering, then suddenly shifts to a high pitch tone that is really weird, whenever I'm north of 2500RPM. Service light turns on. Every single shift is HARD. The whole car lurches no matter how easy I am on the clutch. Just letting off the gas causes the transmission to bounce and clunk like crazy. Hitting higher than 3000RPM causes unpredictable engine behavior so bad it almost took me off the road. Steering suddenly feels like driving a brick, it barely works. Bluetooth in the radio goes out (I don't know how or why this would be related to anything, but it happened at the same time so I am reporting). I was able to limp home barely, but the drive was nuts. Very unsafe to drive in this state.

I thought maybe I had a bad wheel hub or something at first, when the Advancetrac service came on, because I looked that up here in the forums when the initial problem started. But now, I have no effing clue where to start. Everything has gone insane in the car. Any ideas?

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[db252]

First thing I'd look at is your grounds. Check the ones by the lower right side of the radiator and then then the ones on the drivers fender wall hidden by the air filter box (stock or aftermarket either way will have to come out to get a look).

 

[Schwerin]

I agree with above. Sounds like a grounding or ECU issue.

 

[15wile]

Checking... will report back this evening.

 

[Roger Blose]

Could be a battery going bad giving the electronics a tough time. At the four year mark, your battery needs to be replaced for sure.

 

[GT Pony]

Could be a battery going bad giving the electronics a tough time. At the four year mark, your battery needs to be replaced for sure.

I agree with this ... put a new battery in it (it's about time for that anyway) and see if that helps.

 

[15wile]

Update. Replaced battery. Looked for ground shorts - could not discover anything. No engine error codes after reset - but ABS and Advancetrac service light still on. Traction control, hill start, etc... all off. But car is drivable now.

Apparently my SCT device does not give me ABS error codes, so I don't know where I can obtain that info. Drove around for a while and started up/shutoff a few times to see if error would clear on its own. It did not.

 

[GT Pony]

Update. Replaced battery. Looked for ground shorts - could not discover anything. No engine error codes after reset - but ABS and Advancetrac service light still on. Traction control, hill start, etc... all off. But car is drivable now.

Apparently my SCT device does not give me ABS error codes, so I don't know where I can obtain that info. Drove around for a while and started up/shutoff a few times to see if error would clear on its own. It did not.

Go into "Engineering Test Mode" and see if there are any DTCs showing. If so, you should be able to clear them there. The DTC screen is shown at time 0:32 in the video below.

 

[15wile]

It shows the code. DTC code c41500.

It does not allow me to reset. Driving the car around a bit in engineering mode does mark the "x" for "current" DTC and not just historical.

 

[GT Pony]

It shows the code. DTC code c41500.

It does not allow me to reset. Driving the car around a bit in engineering mode does mark the "x" for "current" DTC and not just historical.

I think you can only delete history codes. Maybe try getting into Engineering Mode with the engine off and see if it will clear. But if it's a problem fault going on in real time with the engine running it will probably just set the DTC again.

 

[15wile]

The problem isn't with the engine now, near as I can tell. My SCT reader doesn't even see the code in question - and I've run clear all dtc codes anyway. I think this is ABS related. Googling the code *seems* to point that way too, but there's almost no documentation on what this code means.

 

[ForYourOwnGood]

Did you lose a reluctor wheel on one of the hubs? I've seen those come loose and spin causing all sorts of havoc. Or an abs sensor? Check the cables for damage too.

Have you tried just unplugging the potato by the air box to see if killing advancetrac helps?

 

[erikkire18]

you probably blew a fuse, thats what happened to me. the power steering didn't work nor hill assist. it the power steering rack I think? but i blew a fuse and ford fixed it for i think $85 can't rememeber

 

[Nos-pete]

Am having same issue with 2020 gt500 did you get the repair to this problem ??

 

[15wile]

Am having same issue with 2020 gt500 did you get the repair to this problem ??

Problem turned out to be the wheel hub after all. One of the sensors got loose, and the wheel partially destroyed it. The hub itself took some damage in the affair. The sensor was sending out bizarre, nonsensical data, causing the car's ECU to go haywire, shut off the ABS system, and put the engine into some kind of limp mode.

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