2015 Mustang gt limp mode

[Brandongt]

I have had my car for 9months had the Intake manifold sensors break, the throttle body sensor go out and the gas pedal sensor went out, replaced all of it and now I’ve got the same gas pedal position sensor code, I was wonder if anyone has any ideas on what could be the problem,
Thank you

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[Rapid Red]

Don't quote me on this, but I believe there is a recalibration proceedure for the pedal sensor.

It might be just simple remove the battery power and reconnect, or hold the pedal on the floor, turn on the ignition, not starting the car to be clear.
I'm sure someone will have a more defined answer for ya...

Stay tuned, BTW that seems like a lot of part failures, all at once. What's the real story behind that?

 

[Brandongt]

bought the car used, started putting aftermarket parts on, cold air Intake, exhaust, had it tuned, so on maybe 3 months after all that the car threw a throttle body position sensor code had replaced it and went back to driving it then a week later it through the intake manifold code for the 2nd bank sensor went bad the metal pole has broke off replaced it with a 2017 mustang gt pp intake, then a day or two went by and the gas pedal position sensor went out replaced it and then it started throwing it again so I sent it to ford to see what they could find they said that it was failing on my gas pedal end but that couldn’t be the problem since it was just replaced, they said the tune could have messed up the pcm but they aren’t 100% on anything other then there computer say it’s fail on the gas pedal end.

 

[Brandongt]

Now the car will through the gas pedal position code, hit limp mode but the check engine light won’t come on, that’s the one part that truly stumps me

 

[ugstang17]

There is no recal for changing our the pedal sensor in the tech manual for the 11-14 GT. That said much has changed on the S550 in regard to the electronics. So I will not speculate further on that matter.

Several things here to consider given you have not provided details...

Q: Limp (wrench light) mode each time? Or CEL (engine) light code? Or simply a stored code?

Q: Have you taken the time to pull the intake tube off, put the car in KOEO (press/release the start button without brake pedal depressed) and have someone slowly press the pedal down as you observe the TB blade movement? THe TB should move between about 2% to 85% closed to open on full stroke.

Q: Have you taken the time to chase the cable back to the PCM (ECU, ECM, brain) and inspect for damage and/or loose connection at the PCM?

Q: Have you checked integrity of the cable with a multimeter to verify continuity?

Q: Are you using new parts and if so are they quality parts? Could be a bad part out of the box. Happens in all trades of electro-mechanical work. Trust me I know.

Observation - The replacement procedure for the 11-14 GT pedal does not speak of a calibration process in the Ford Tech Manual I have. It only warns of not doing the replacement with power on the car to avoid codes. So if you performed this with the battery connected you may need to do the "power-down-pat" process of disconnecting the battery and resetting OR performing a KAM reset and PCM code reset through a device if you have one. Keep in mind CEL and LIMP mode codes will not reset themselves in some cases.

Good luck.

 

[Brandongt]

The parts that I have replaced are with brand new parts, I have checked wiring on the ecm and tbs/pedal sensor, I haven’t taken the intake tube off I’ll give that a shot and see what I can, and I haven’t check with a multimeter, but it throws the wrench light every time, I did the pedal sensor relearn it drove fine for a bit but then went right back in to limp home mode after maybe 15mins of driving

 

[Brandongt]

Took the intake tube off had someone press the pedal and the tb open and closed fine, no issues with it, now all that’s left is to check the cables

 

[ugstang17]

Limp mode is being caused by the Throttle positioning system correct? Many other things on these S550+ cars can create that limp mode state and the newer the model the more limp mode issues can arise. In the days of simplicity not too many moons ago, limp mode was only caused by throttle position system (TB and Pedal signals) MAF IIRC and one other I cannot think of off hand. That was about it.

Keep in mind that there is redundancy built into this system. There are two signals at minimum talking to the PCM. The pedal has two and the TB has two. If the PCM fails to see both of these signals on either device you will have a failure. The fact that you have movement throughout indicates to me that the PCM is responding to the input from the pedal and the TB is responding to the PCM correctly. (They are not directly linked in newer cars since Torque based Throttle Positioning was conceived adn now used virtually industry wide). What is likely missing is the redundant signals would be my conclusion. I cannot recall if the signals are designed to cancel each other or compliment each other directly. But there will be two on each device minimum. Unfortunately this is ALL theory based on 05-14GT manuals and my own research on tuning theory I have done through reading. I do nto have access to S550 manauls. So with all the addition of body modules, and a newer PCM than the 11-14 and different strategies at work there may still be a need to access the PCM to accept the pedal signals at idle and throughout the span of the output (shoudl be a 1-5vdc range output based on common analog output signal ranges) and store those. Once you've rung out your cables should you find nothing and you have verified your pins in your conectors have not gotten pushed out or are failing to make connection (it happens) that would be the only thing left to consider which may mean a trip to Ford or someone with a device adn the procedure to resolve the recognition of the new device and its outputs should that be the case.

Don't forget your motor side on the TB as well. If the throttle motor or flap is catching or hanging up through the motion this will be enough to flag a Limp mode as well because the PCM will see that the TB position is not keeping within the following tolerance of the command value. Won't take much. The same can occur if the motor begins to move and the flap has not yet begun to move due to lost motion i the gear drive or again binding in the motor gear drive.

Gotta run. Celebrating 25 years of marriage today.......yes to the same woman.

 

[Brandongt]

The wiring is fine no issues that I can see looks perfect so it looks like I’m gonna have to take a trip to ford again and see what they say I guess, thank you for the advice and help this has been killing my brain not being able to figure this out

 

[Rapid Red]

bought the car used, started putting aftermarket parts on, cold air Intake, exhaust, had it tuned, so on maybe 3 months after all that the car threw a throttle body position sensor code had replaced it and went back to driving it then a week later it through the intake manifold code for the 2nd bank sensor went bad the metal pole has broke off replaced it with a 2017 mustang gt pp intake, then a day or two went by and the gas pedal position sensor went out replaced it and then it started throwing it again so I sent it to ford to see what they could find they said that it was failing on my gas pedal end but that couldn’t be the problem since it was just replaced, they said the tune could have messed up the pcm but they aren’t 100% on anything other then there computer say it’s fail on the gas pedal end.

The only thing that has not changed as of now, is the "tune". I would go back to the factory tune and see what happens. All those parts going south like that does not make sense .

The 2 upgrades "cold air Intake, exhaust" should run just fine with the factory tune. Not knowing what cold air intake is used.

Something I can pass a long regarding the cold air intakes. The type that allow for a soft tune to be added. Will generally come with an insert that is to be removed before the tune, inserted if no tune is to be added.

It is easy for Ford to say oh well it has a tune, we cannot figure it out. To be fair, if the car had say the Roush, CAI & tune. they would be hard pressed not to look at it closer. No name tunes or tuners, that response would be a reason and legit .

 

[Brandongt]

I have the roush cai, with the stock flash on it now, after all the parts went bad I had it reverted and put the stock air box on it and tried driving the car a few weeks ago and it still did the same thing, had a few people tell me my pcm is messed up now or my gas pedal is just bad since it’s only reverting back to the gas pedal code.

 

[Rapid Red]

Interesting, well we know its not the tune, and I know removing and reinstalling the the CIA there was plenty of time for the PCM to reset, and clear codes.

Are you doing your own flash, asking cause the Roush down load does look for problems before it will run. I remember seeing a menu that looked like it would also run some diagnostics.

One more question what dongle are you using if doing the flash yourself? The soft tune suggest 2 specific brands. When the application launches they are seen and can be selected, yes other hardware can be used .............. But, me thinks if Roush makes a suggestion and we are using a product that is engineered by same...... A wise choice or best practice is to follow the lead.

Has anyone mentioned what would be the problem with the gas peddle, is it drive by wire? I would think that would be suspect and not the PCM.

An after thought, now with the car returned to stock, the code is returning. Why not take it back to Ford, have em run factory diags. It will be a lot cheeper than guessing, and less frustration in the long run.

Then you can choose to make the repair yourself, or they could offer a package deal, diags and part replacement ?

What year is the car how many miles, just for grins ?

BTW the Roush CIA & Soft tune IS kick ass, you will love it when you get this sorted out.

 

[Brandongt]

2015 with about 74k, even at stock I took it to ford they had it for 2weeks checked it over with it being the stock set up checked the wiring, all they said is the computer they are using is showing that the gas pedal is failing on it end, and reflashed it and sent it home and said I may still have problems, Ford hasn’t really helped in this situation hence why I’m trying to figure out other possibilities that may cause this problem, I had bama write most of the tunes after data logging the car.

 

[ugstang17]

Without being able to monitor both signals (helps to have a wiring diagram as well as a multimeter (two work better in this case so you can see both signals at once) you are unable to discriminate further. If the voltage from the PCM are good and the signals sweep smoothly from both devices at the PCM then that ultimately points at the PCM using simple process of elimination.

From an opinion of seeing more and more posts like this it appears that the automotive industry is suffering from a lack of good troubleshooters AND good management that will allow them to do so or try to do so. There are just some jobs that can't be done by a flat rate labor manual. In some instances a problem has to be addressed based on time and material. Sorry for you misfortune.

 

[Brandongt]

its alright, I see it like this if I have to replace a pcm, then I’ll do so, but if the problem still persists after that I’m truly gonna be at a loss as far as what could truly be causing the problem, just gotta take one step at a time.

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