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Discussion Starter #1
I have read and read about this issue trying to figure it out. My 94 bronco has had some shifting concerns now for about a month....it started with harsh 1st to 2nd and 2nd to 3rd. It would only do this every now and then pulled the codes and got 452 cleared the code and continued to drive to see if it came back. Over the next week or so it drove great then all of a sudden it started shifting hard again only this time it would go into a neutral state when it shifted into 3rd gear. Here is what I have done.....drain fluid and change filter, new vss (it is aftermarket and reads 1800 ohms bought one from the dealer it also read in the 1800 ohms), mlp sensor, psom, checked every fuse. Did a ac voltage test at the pcm pin 3 and 6 just the other day. From 0 to 50mph the highest reading was 12 and from what the book says it should be no more or less than 4 anything over 4 volts replace pcm. So my question is has anyone else made this 250-400 dollar decision and it fixed the problem. Also while hooked to the scanner ran data and whached the vehicle speed as soon as it jumped to neutral I lost all speed data on the scanner. But if I am driving down a hill and it jumps to neutral as I cost faster my speedometer reads faster. Any help would be nice THANKS!!!!
 

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aka: kemicalburns
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7,830 Posts
is your ABS light also on by chance? if so you may have a faulty ABS module.
 

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2006 Lincoln Navigator
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I pulled out my Ford service manual to find the same troubleshooting procedure. I read the step that asks if the voltage is greater than 4 volts at 50MPH to mean the signal to the PCM should be greater than 4.0 volts. The VSS signal does feed into the RABS module as noted before. The RABS module should have an impedance of 1300-1550 ohms. I would suspect more of a wiring issue, intermittent connection somewhere more than a bad PCM.
 

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Discussion Starter #4
no ABS light and no codes on the ABS, I have checked all the points for breaks and shorts provided in the service manual already with no luck. Electrical is the worse problem to have!!!!!!
 

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2006 Lincoln Navigator
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1,488 Posts
It gets really bad when the electrical problem was caused by squirrels chewing on the wires. Ask me how I know....
 
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