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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 48624
Experience:  16 years experience
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I have been fighting a speedometer issue. Truck is an 05

Customer Question

Hello, I have been fighting a speedometer issue. Truck is an 05 f250.for the last 2 years about 2 to 3 times per year speedo would bounce around or drop out for a few minutes but would clear up and have no issues for 6 months then randomly it would start up again..
well now it is consistently not working. When you first start the truck to leave it will work for the first couple of miles but as it warms up it starts bouncing a little, then as it gets worse will bounce 20-80 mph, next it will then just sit at zero,
what ever the speedometer on the dash reads my scan gauge reads the same which leads me to believe it is not a cluster issue. I have no abs light, cruise control will still turn on and work until speedo bounces around then it tries to stay caught up to what ever the speedo is reading. I went ahead and ABS in rear diff, no difference which I didn't expect to fix the issue.
Just came inside from running my AE on it. when logged into the abs system, both front and
Submitted: 1 year ago.
Category: Ford
Customer: replied 1 year ago.
Just came inside from running my AE on it. when logged into the abs system, both front and the rear speed sensors are reading in sync and correct. logged out of abs system and into trans system, pulled up vehical speed sensor, input and output speed sensors, input and output are reading what i would expect, but vehical speed sensor when logged into the trans system is reading same as speedo for most part, speedo was jumping around a little but sitting at zero most of the time and the vehical speed sensor never went over 0.2.My next question is wear is this vehical speed sensor? everything im finding says the vss is in the rear diff, which is incorrect atleast for the speedo side of things since abs module is reading correctly.ALso have found 1 or 2 acticles saying something about wiper motor? Any other info on thisThanks for any and all help
Expert:  Chris (aka- Moose) replied 1 year ago.

Welcome, I'm Chris and independent contractor that helps customers here.

The speed signal is produced by the ABS module. It monitors all the wheel speed sensors and averages them to come up with a VSS reading. It then sends that signal out to all modules and components needing this reading. If the transmission shifts poorly during this issue and there is a 0500 code stored then a replacement ABS module is the fix as long as the ABS module shows incorrect VSS. If the ABS does show correct VSS then there is a concern with pin 21 gray/black wire broken or shorted. Below is a diagram.

Thanks for letting me assist you. I hope I met all your expectations.

Please make sure to complete the required rating when ready so I am compensated by the website from the site and question fees you have already been charged. If your not able to rate my response, let me know why, so I can help more, and stay in contact with you.

Customer: replied 1 year ago.
With my autoenginuity scanner the ABS system doesn't show a VSS signal only ABS speed sensors from both front and the rear sensor. All three of those sensors are reading and in sync with one another. But if I log into the transmission system it does show me a vehicle speed sensor reading and that's the one seems to be acting up.I did have codes p0500, p0503, and u2023.With the problem having the consistency lately I'm more apt to lean towards the module than a wiring issue
Customer: replied 1 year ago.
Do you know of a test procedure to verify an abs module problem?
Expert:  Chris (aka- Moose) replied 1 year ago.

The test that is needing to be done on the ABS, your tool is not able to perform sense it is not able to look at all the PIDs for the ABS module. With the given information it is looking most like the ABS module faulty here.

Customer: replied 1 year ago.
I will be sure to rate your service as soon as I get the part replaced to verify the diagnosis. thank you for your help
Expert:  Chris (aka- Moose) replied 1 year ago.

No problem, we have till the 8th prior to the post closing.

Expert:  Chris (aka- Moose) replied 1 year ago.

I like to stay in contact with my customers that appear not pleased, still working on the concern, or have not rated yet. I assume you were not pleased with my help. I hate that you have spent money to get an answer but left not happy. Can you tell me why, or can I help more. If its more help you need just reply and we can pick up where we left off.

Thanks Chris

Customer: replied 1 year ago.
Haven't been able to perform the repair yet, have been out of the country for the past week.
Expert:  Chris (aka- Moose) replied 1 year ago.

Thanks for the update.