Speedo not working, why?
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Speedo not working, why?
my speedo does nto work and my abs light is on and the o/d off light flashes i replaced the senser in the rear end and that has not fixed the problem anymore idea out there to help me it would be greatly appreciated!
Senior User
Joined: Dec 2004
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From: York, PA
interesting...my wife keeps telling me that when she is pulling her horse trailer that several times the speedo does not work until a couple of miles down the road. I have not witnessed this problem yet though.
Could there be common speedo related issues with SD's?
Could there be common speedo related issues with SD's?
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my truck is a 1999 and the speedo does not work the abs light is on and the od light flashes the ford dealer said it was a fuse but everyone is telling me that it is the vss so i replaced that and it still has not solved the problem i was recently in an accident on the front drivers side and thats when it all happed so if any one has more suggestions other than the vss let me know it would be greatly appreciated
Elder User
Joined: Jan 2003
Posts: 828
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From: Baltimore
Does it sound anything like this?:
https://www.ford-trucks.com/forums/7...n-4x4-low.html
- Ron
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my truck is a 1999 and the speedo does not work the abs light is on and the od light flashes the ford dealer said it was a fuse but everyone is telling me that it is the vss so i replaced that and it still has not solved the problem i was recently in an accident on the front drivers side and thats when it all happed so if any one has more suggestions other than the vss let me know it would be greatly appreciated
check your abs module connection. it's in the front drivers side of the truck and if it comes unplugged or is damaged it will do what you described
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Senior User
Joined: Dec 2004
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From: York, PA
///M Puller - Does your wife have this problem when starting out in 4x4? Does the speedo start out ok showing a slow speed and then go to 0 for a few miles?
Does it sound anything like this?:
https://www.ford-trucks.com/forums/7...n-4x4-low.html
- Ron
Does it sound anything like this?:
https://www.ford-trucks.com/forums/7...n-4x4-low.html
- Ron
Elder User
Joined: Jan 2003
Posts: 828
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From: Baltimore
///M Puller - I recently had a Ford Field Engineer look at my truck and gather data on this problem. After looking at information about the logic in the PCM, he was able to predict exactly when this problem would occur. We took my truck to a test site, set up his scenario and reproduced the problem.
The gist of it is that medium engine load combined with very slow speed and relatively high RPMs will temporarily kill the speedometer in these trucks. The PCM decides that the speed does not jive with the engine parameters and the PCM then kills the speed signal. I was told that Ford will not fix this problem because it has not been seen in a large enough number of trucks. I guess the real problem is that very few people use their trucks like trucks anymore.
The gist of it is that medium engine load combined with very slow speed and relatively high RPMs will temporarily kill the speedometer in these trucks. The PCM decides that the speed does not jive with the engine parameters and the PCM then kills the speed signal. I was told that Ford will not fix this problem because it has not been seen in a large enough number of trucks. I guess the real problem is that very few people use their trucks like trucks anymore.
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The gist of it is that medium engine load combined with very slow speed and relatively high RPMs will temporarily kill the speedometer in these trucks. The PCM decides that the speed does not jive with the engine parameters and the PCM then kills the speed signal. I was told that Ford will not fix this problem because it has not been seen in a large enough number of trucks. I guess the real problem is that very few people use their trucks like trucks anymore.
Definitely check on the ABS module's connections.
Elder User
Joined: Jan 2003
Posts: 828
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From: Baltimore
To reproduce it:
1) Put the truck on a steep hill on a loose surface ( grass, gravel, dirt ). Or, put a lot of weight in the truck bed and do this on a level surface. The hill has the same effect as putting alot of weight in the bed. The idea is to force the engine to generate more torque and RPMs to move.
2) Put the truck in 4x4 low.
3) From a dead stop, accelerate fairly quickly to about 2.5 mph and hold this speed.
If the engine load is about 40% and the RPMs are around 1300 and the speed is about 2.5 mph ( it needs to be like this for maybe 5 seconds or so ), the speedometer will drop to zero and stop working. A few people have now seen this in their trucks. There is an issue in the decision logic in the computer software and this scenario causes it to decide that the speed input is bad.
If you don't use 4x4 in a low-speed high torque situation, you will never see this problem.
Apparently Ford corrected this with the new software delivered with the 6.4L motors.
