Post Flash Tone
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Post Fiend
Joined: Apr 2004
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From: North of Salt Lake City
Post Flash Tone
Ok folks. I recorded the sound while I was changing the oil today. Listen closely to this video and tell me if you're hearing this tone also. Wondering what the heck it is.
YouTube - 2011 Super Duty Post 10B17 Tone
YouTube - 2011 Super Duty Post 10B17 Tone
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Post Fiend
Joined: Apr 2004
Posts: 5,158
Likes: 35
From: North of Salt Lake City
I get the sound with the hood closed so it can't be that. It also happens when any door is opened, not just the drivers door.
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Post Fiend
Joined: Apr 2004
Posts: 5,158
Likes: 35
From: North of Salt Lake City
Hey, I just want to add one more piece to the puzzle. You can hear the tone right before the EGR valve actuates 30 seconds after shutdown. Listen to this video closely right before the valve moves and you can hear the tone. It's more clear in the engine compartment so I'm starting to wonder if it's some kind of relay or something.
It would be easy for someone else to check. Just shut down your truck with the hood open and run around to the passenger side and watch for the EGR valve actuation. If you hear this tone right before, then I'm not crazy.
http://www.youtube.com/watch?v=ycp7WYPpJAo
It would be easy for someone else to check. Just shut down your truck with the hood open and run around to the passenger side and watch for the EGR valve actuation. If you hear this tone right before, then I'm not crazy.
http://www.youtube.com/watch?v=ycp7WYPpJAo
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Also, I don't have the new flash yet, but I don't have that tone when I open the door. I messed with a few things in the truck, changing some settings and couldn't duplicate it. I plan to get the new flash this week, so I'm interested to see if I get the tone after.
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Hey, I just want to add one more piece to the puzzle. You can hear the tone right before the EGR valve actuates 30 seconds after shutdown. Listen to this video closely right before the valve moves and you can hear the tone. It's more clear in the engine compartment so I'm starting to wonder if it's some kind of relay or something.
It would be easy for someone else to check. Just shut down your truck with the hood open and run around to the passenger side and watch for the EGR valve actuation. If you hear this tone right before, then I'm not crazy.
YouTube - 2011 Ford Super Duty EGR Valve Actuating
It would be easy for someone else to check. Just shut down your truck with the hood open and run around to the passenger side and watch for the EGR valve actuation. If you hear this tone right before, then I'm not crazy.
YouTube - 2011 Ford Super Duty EGR Valve Actuating
It sounds like that valve actuator returns to it's "at rest" position after the truck is off and loses vacuum. You can kind of hear a sucking sound when it releases.
I don't have the flash yet as I had the dealer hold off when I bought the truck so I could feel the difference. Maybe at the first oil change I'll have them do the flash.
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Post Fiend
Joined: Apr 2004
Posts: 5,158
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From: North of Salt Lake City
I just learned another thing, I can hear the sound when I press the unlock on the remote key. And the sound is definitely coming from the engine compartment. A good way to hear it is to stand at the passenger front fender and press the door unlock on the key. The truck has to have been sitting for 10 minutes or so and you only get one chance to hear it. Then it has to sit idle for several minutes again before I can duplicate the sound. Now I'm thinking it's some kind of relay that loads a capacitor in the PCM.
Tuned
Joined: Jul 2010
Posts: 408
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From: Canada
The only other thing I can think of is the actual EGR valve is a DC motor - it almost sounds like a DC motor so maybe the PCM sends signal for the valve to reset its limit travels as part of a shutdown routine.
Those are my two guesses based on what I just heard from my motor - but I have not tried to induce the same tone via just a keypress - only after shutting the motor down.
More exploration necessary - I'll be back...
Those are my two guesses based on what I just heard from my motor - but I have not tried to induce the same tone via just a keypress - only after shutting the motor down.
More exploration necessary - I'll be back...
Tuned
Joined: Jul 2010
Posts: 408
Likes: 2
From: Canada
Okay did the keypress only - it definitely sounds like a servo motor which would make sense re: EGR valve. It only lasted a couple of seconds - much less duration than the shutdown.
I'm leaning towards the EGR valve -I am betting the PCM sends a signal when the key unlock routine is initiated to move the EGR valve in anticipation of engine start. That likely starts a timeout countdown that if the engine does not start within a certain period the EGR valve is returned to the original position - which could explain Epic's experience of hearing the noise when he seemingly did nothing at the time.
Further, upon shutdown, the PCM sends a signal to the motor to reset the servo limits and/or set the initial starting position which is why you hear it for quite a bit longer after shutdown.
Next steps to support my theory:
1) Listen for tone/noise on remote start sequence - if my theory is correct, this should happen as part of the delay process prior to engine ignition.
2) Door unlock - Determine timeout period and listen for valve returning to original position when engine not started.
I'm leaning towards the EGR valve -I am betting the PCM sends a signal when the key unlock routine is initiated to move the EGR valve in anticipation of engine start. That likely starts a timeout countdown that if the engine does not start within a certain period the EGR valve is returned to the original position - which could explain Epic's experience of hearing the noise when he seemingly did nothing at the time.
Further, upon shutdown, the PCM sends a signal to the motor to reset the servo limits and/or set the initial starting position which is why you hear it for quite a bit longer after shutdown.
Next steps to support my theory:
1) Listen for tone/noise on remote start sequence - if my theory is correct, this should happen as part of the delay process prior to engine ignition.
2) Door unlock - Determine timeout period and listen for valve returning to original position when engine not started.
Tuned
Joined: Jul 2010
Posts: 408
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From: Canada
Okay more testing - there are actually two different sounds - its definitely the EGR valve and/or the DEF reductant pump. It seems that on keypress (lock or unlock) the EGR valve does a self check (probably a position check).
On shutdown, the DEF pump is sucking DEF out of the lines - this is louder than the EGR valve motor and accounts for most of the tone. The DEF pump is controlled by a pressure sensor which the PCM continuously monitors. It is not clear if the PCM monitors this sensor after ignition shutdown but it seems to be an active sensor so it may be able to send a wake signal to the PCM which could then activate the pump - but that is pure speculation on my part.
Anyways, I'll do some more testing tomorrow, but I am pretty sure its all good!
On shutdown, the DEF pump is sucking DEF out of the lines - this is louder than the EGR valve motor and accounts for most of the tone. The DEF pump is controlled by a pressure sensor which the PCM continuously monitors. It is not clear if the PCM monitors this sensor after ignition shutdown but it seems to be an active sensor so it may be able to send a wake signal to the PCM which could then activate the pump - but that is pure speculation on my part.
Anyways, I'll do some more testing tomorrow, but I am pretty sure its all good!