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Part throttle limp mode and wrench light

I posted about this issue last fall, but can't find the thread. I just had this part throttle, car falls on its face and throws a wrench light issue again getting onto the interstate. It seems to happen when holding part throttle at a steady state around 4k rpm. I was waiting for an opening to get into traffic when it happened and I had to pull onto the shoulder, shut the car off and restart. It is like it's going into the Electronic Throttle Control Fail Safe Operation Mode as described about halfway down this page: http://www.aa1car.com/library/throttle-by-wire.htm

The problem is it doesn't leave a DTC. The code I was getting last year (if I checked before shutting off the engine) was related to a diesel engine, but I can't find it now. However, as soon as you restarted the car it would clear itself. It also doesn't throw a CEL, just the wrench light. I had a data recorder hooked up to it for about 10 days late last summer, but of course it would never do it. It's really a dangerous situation especially when on a busy interstate. The only other place it has happened was during the caution lap at time trials last year, which really sucks because you have to pull off go through the hot pits and restart.

It's strange that no one else is having this issue. I'm really getting tired of electrical issues on this car.......
 
It does sound like the PCM lost the signal from the throttle. This is somewhat common with GM cars when the throttle body gets dirty and the butterfly valve sticks in reference to the TPS signal.
 

steveespo

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Beat me to it Mike. Gary pull off the air inlet tube and check the TB blade for carbon build up or excess oil. Push it open by hand and check the backside with a flashlight. Use a paint brush and paper towels sprayed with TB cleaner to clean as much as you can. Don't spray the cleaner directly in there, I don't like risking getting it inside the gears through the shaft seal.
It may be a bad connection at the throttle body or gas pedal too, have you mechanic run the Throttle position sensor diagnostic flowchart, damn electrical gremlins are hard to find.
Steve
 
About a month or two after I got my car it did that to me when I was making a left turn at an intersection, scared the crap out of me because cars were coming. Hasn't happened since and I've had it close to 3 years 17k miles. Hope you get it worked out. It seems like a intermittent connector problem, one minute all is well the next a key signal is gone for a millisecond.
 
steveespo said:
Beat me to it Mike. Gary pull off the air inlet tube and check the TB blade for carbon build up or excess oil. Push it open by hand and check the backside with a flashlight. Use a paint brush and paper towels sprayed with TB cleaner to clean as much as you can. Don't spray the cleaner directly in there, I don't like risking getting it inside the gears through the shaft seal.
It may be a bad connection at the throttle body or gas pedal too, have you mechanic run the Throttle position sensor diagnostic flowchart, damn electrical gremlins are hard to find.
Steve
I did check the TB last time it happened and it was clean as a whistle and operated smoothly with no sticking. Guess I could look again. Might need to have him run the diagnostic. Like racered said it is VERY intermittent. ......
 
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It's very strange that you're not throwing any codes. I've had my car go into limp mode plenty of times but I always ended up with a code of some sort. Keep us posted...
 

steveespo

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cloud9 said:
I did check the TB last time it happened and it was clean as a whistle and operated smoothly with no sticking. Guess I could look again. Might need to have him run the diagnostic. Like racered said it is VERY intermittent. ......
Sound like connector or broken wire that loses contact.
 
steveespo said:
Sound like connector or broken wire that loses contact.
I think you're right. Unfortunately since it's not leaving a code and I can't replicate it the diagnostic probably won't uncover the source?

By the way just had the door harness on the passenger side replaced due to the speaker cutting out routinely. The tech told me it's a chronic issue on the F150s and heard at his last in-service that they were going to even lighter gauge wire on the new platform.......
 
Ok, I've had this issue pop up twice now this spring. Tech called the Ford Hotline and they went straight to:

"Replace Engine Fuel Control Module". It's part # AU5Z9D370K It took about 10 seconds to replace. It's located in the spare tire well. Cost was about $25.00

I'm hoping this solves the problem. Sounds like it's happened before since they didn't even have him run through any other diagnostics but pointed straight to the control module.
 
Tucson302 said:
I had this happen to me during three seperate sessions last time out at INDE so I sure hope this works.
Did it happen under WOT or part throttle? It was the wrench light and not the flashing check engine light correct?
 

Tucson 302

2013 Black LS #439
cloud9 said:
Did it happen under WOT or part throttle? It was the wrench light and not the flashing check engine light correct?

It was only at WOT and yes just the wrench no CEL. As you stated turning the car off clears it but that's a huge pain while on track I had to pull into the dirt
 
Tucson302 said:
It was only at WOT and yes just the wrench no CEL. As you stated turning the car off clears it but that's a huge pain while on track I had to pull into the dirt
Well I'll let you know if it fixes it, but it's so intermittent that I'm not sure at what point I'd be confident saying it's gone.......

That said for $25, I'd just buy one or get your dealer to replace it if still under warranty. Mine was past the 3 year mark so I had to buy it.
 

Tucson 302

2013 Black LS #439
cloud9 said:
Well I'll let you know if it fixes it, but it's so intermittent that I'm not sure at what point I'd be confident saying it's gone.......

That said for $25, I'd just buy one or get your dealer to replace it if still under warranty. Mine was past the 3 year mark so I had to buy it.

Since the part was only $18 at Levittown I already ordered it
 
That's not considered drivetrain?
 

steveespo

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But maybe emissions warranty? fuel system device, that module is what regulates the pump output I believe. Our pressure and volume is regulated by the amount of voltage sent to the pump, there is no return line so duty cycle is what regulates how much fuel is sent o the injectors.
Steve
 
steveespo said:
But maybe emissions warranty? fuel system device, that module is what regulates the pump output I believe. Our pressure and volume is regulated by the amount of voltage sent to the pump, there is no return line so duty cycle is what regulates how much fuel is sent o the injectors.
Steve
I dunno. He just puts the VIN in the system along with mileage and it tells him if it's covered and I guess this one wasn't. On the other hand my son's keyless entry pad on his Focus bit the dust last Saturday, literally 2 days before the bumper-to-bumper warranty expired so I caught a break there :)
 

Tucson 302

2013 Black LS #439
Gary quick question so I don't break anything trying to get that plug off the control module, where do you press on it to release?

EDIT: Figured it out, lets hope this works!
 

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