Excursion Trans Help.....
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Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
From: Henderson, Nv
Excursion Trans Help.....
We have a 2000 Ford Excursion V10 4x4. Came up with fault codes P0503, P0720, P0722. I went ahead and changed all sensors (TSS, OSS, and VSS). Codes still coming up after cleared. Pulled the negative battery cable off and cleaned and checked for any other corrosion. All fuses and relays are good. What steps does anybody suggest next? Any help is greatly appreciated.
More Turbo
Joined: Nov 2011
Posts: 608
Likes: 1
From: Weston Fl.
Does your dash work when it goes limp? I had a similar issue on a minivan and it ended up being a the instrument cluster. Turned out that the cluster was bad and didnt send the trans the signal to change gears. I had changed all the sensors and nothing worked. someone had a quick fix by welding some cracked connectors that weren't making contact in the cluster. I gave it a shot since i had not many choice. it worked to my surprise. I was vey exited but mad at the same time because of all the money the guys at advance made me spend with speculating. A few months later it happened again and i could never get it back to work. i figured i would just by a whole new cluster and call it a day. i had to drive on 2nd gear for a while till it just thru a rod out of the oil tank and thus making me buy this beast.
This might only apply to you if your speedometer needle won't move. keep us posted!!1
This might only apply to you if your speedometer needle won't move. keep us posted!!1
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,695
Likes: 2,616
From: SE Florida
The instrument cluster has NOTHING to do with those codes. Good diversion to get him to do useless work!!
You have a wiring problem, most likely the signal return from the speed sensors. The codes you had don't always mean the sensors are bad, it just means the PCM isn't seeing the signal. Damaged or corroded wiring is the most likely cause of these codes.
You have a wiring problem, most likely the signal return from the speed sensors. The codes you had don't always mean the sensors are bad, it just means the PCM isn't seeing the signal. Damaged or corroded wiring is the most likely cause of these codes.
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Freshman User
Joined: Aug 2010
Posts: 29
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From: Henderson, Nv
I think its in the alternator. After spending hours and finding nothing I read on another site (googled) that it could be the alt. I charged the battery and unplugged the alt. It usually goes into limp (CEL) mode within 5-10 miles. Put prob 40 with lots of citing driving as well as stopping often to turn the truck off. Keeping my fingers crossed...Thanks for the leads.
New User
Joined: Nov 2010
Posts: 17
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How does the Alternator have anything to do with the trans shifting hard and going into limp mode?
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Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,695
Likes: 2,616
From: SE Florida
I've actually seen this happen.
A diode fails in the alternator. The diodes are there to convert the AC current that an alternator produces into DC current. If one fails an AC ripple appears superimposed on the DC current. This ripple can be interpreted by the PCM as input from the speed sensors. It modifies the speed signal, causing all kinds of havoc in the calculations. When it gets bad enough there are algorithms that determine that the signal is bad because what it is seeing isn't possible. Sometimes it will change from 1500 RPM to 6000 RPM and back to 1400 RPM in less than 500 mSeconds. The PCM knows that this is impossible, so it declares the speed signals bad and goes into limp mode.
A diode fails in the alternator. The diodes are there to convert the AC current that an alternator produces into DC current. If one fails an AC ripple appears superimposed on the DC current. This ripple can be interpreted by the PCM as input from the speed sensors. It modifies the speed signal, causing all kinds of havoc in the calculations. When it gets bad enough there are algorithms that determine that the signal is bad because what it is seeing isn't possible. Sometimes it will change from 1500 RPM to 6000 RPM and back to 1400 RPM in less than 500 mSeconds. The PCM knows that this is impossible, so it declares the speed signals bad and goes into limp mode.
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More Turbo
Joined: Nov 2011
Posts: 608
Likes: 1
From: Weston Fl.
[quote=Mark Kovalsky;11091630]The instrument cluster has NOTHING to do with those codes. Good diversion to get him to do useless work!!
quote]
It just was just a suggestion. Like the ones you've made. FYI it's not a diversion to get him to do useless work. It's called trouble shooting.
If you go back and read my post you'll see that I was referring to my experience and what I did in my situation. I also added that this will only apply to his situation if his gages aren't working properly.
Moving on to the issue,
I found a post by someone with your codes and about the same issues.
Article
I also didn't wanna believe that in my case the cluster would have nothing to do with this but it did.
Here is another excursion owner who actually found the problem with those codes and fixed it replacing the output shaft sensor (OSS)
Hope it works,
Fix
If that don't work try this:
ALL DTC for ford<!-- google_ad_section_end -->
Diagnostic Trouble Code (DTC) Descriptions
DTC - Description Possible Causes Diagnostic Aides
Hope this works for you and remember that we are here to help and suggestions are just that. Goodluck and please keep us posted as the results to your problem, may help someone in the future with the same issues.
quote]
It just was just a suggestion. Like the ones you've made. FYI it's not a diversion to get him to do useless work. It's called trouble shooting.
If you go back and read my post you'll see that I was referring to my experience and what I did in my situation. I also added that this will only apply to his situation if his gages aren't working properly.
Moving on to the issue,
I found a post by someone with your codes and about the same issues.
Article
I also didn't wanna believe that in my case the cluster would have nothing to do with this but it did.
Here is another excursion owner who actually found the problem with those codes and fixed it replacing the output shaft sensor (OSS)
Hope it works,
Fix
If that don't work try this:
ALL DTC for ford<!-- google_ad_section_end -->
Diagnostic Trouble Code (DTC) Descriptions
DTC - Description Possible Causes Diagnostic Aides
Hope this works for you and remember that we are here to help and suggestions are just that. Goodluck and please keep us posted as the results to your problem, may help someone in the future with the same issues.
Post Fiend
Joined: Mar 2009
Posts: 11,798
Likes: 14
From: Mt. Shasta California
The instrument cluster has NOTHING to do with those codes. Good diversion to get him to do useless work!!
You have a wiring problem, most likely the signal return from the speed sensors. The codes you had don't always mean the sensors are bad, it just means the PCM isn't seeing the signal. Damaged or corroded wiring is the most likely cause of these codes.
You have a wiring problem, most likely the signal return from the speed sensors. The codes you had don't always mean the sensors are bad, it just means the PCM isn't seeing the signal. Damaged or corroded wiring is the most likely cause of these codes.
Senior User
Joined: Jul 2004
Posts: 158
Likes: 0
99% its the alternator. Just had an 04 mazda do the exact same thing. The alternator is putting out too much current at higher RPM (say over 1500) and so the trans is forced into a much higher gear and stays there. My mazda6 would force shift into 3rd. Replaced alternator, all is well now. Hope thats the case with yours as well.
Regards,
Josh
Regards,
Josh
Thread Starter
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Freshman User
Joined: Aug 2010
Posts: 29
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From: Henderson, Nv
Im gonna run it as long as I can today on battery only to 100% convince me but ny wife drove it again last night and its still running perfect. Charged the battery now Im gonna run it. Keep you posted...
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