Well the scan tool is called a "Scan Tool" versus just a "Code Reader".

A code reader is limited in what it can do, mainly just read the computers set, or pending trouble codes & erase them.

A scan tool can do that & much more, like read the output of various sensors in real time, so you can see what the various sensors are telling the computer.

A scan tool can save a lot of test time, by being able to sort of get inside of the compuers mind, via the diagnostic port, to see what the various sensors are telling it & how it's responding!!!!

There are many brands of scan tools.
I happen to have a Actron CP9150 kit, with many hook up cables, which with the kits CP9145 scan tool, allows me to access the computers diagnostic port, on all my old & new rides.

So when I have problems I can hook it up to the computers diagnostic port & see what hurts. It saves having to try & test the various sensors individually, which can be a pain to get to & many times you can't test them while driving!!!!

So do a internet search for "scan tool" & read up on whats available now, if your thinking of buying one.

There are some like the Actron, that are portable & hand held & show maybe 5 lines of information, there are others that will use a laptop to display more information on it's screen, so you don't have to scroll through a list to monitor what you want, but it's more bulky & less portable & maybe you don't want to get your laptop greasy & dirty, while messing with the vehicle.

Or maybe one of your local autoparts stores will have a scan tool available on their "Loan-A-Tool" program, that would do, if you don't want to invest in a scan tool, or program for a laptop. They can get pricey!!!!

On the wiring, most of that would likely be labor charges, in checking it & the electrical connectors out.

On the ABS touble codes, if your ABS light is on & you said in your first post that it was, then there are likely ABS trouble codes set, that could offer clues on where to look for this problem, that may save some time. So pulling the ABS codes may be worth while.

Yah I don't think it's likely that the differential is causing your trouble, unless your having some awful problems with it making all kinds of loud strange noises & you've said the truck runs ok.

Typically & as Rockledge has said, with a erratic speed-o & a ABS trouble light, it's the speed sensors fault, but in your case it's not real clear to me just what has been done, nor how the system has been tested.

 

No, no probelms yet..I will inquire about the scan tool at the auto stores and hope they have one in a "loan a tool" program..

 

<TABLE cellSpacing=4 cellPadding=0 width="100%" border=0><TBODY><TR><TD noWrap>RTREV64

I am having the same problems. My ABS light came on and then my speed-o started to act up. The speed-o does not work untill the truck gets above about 35 and then it works like normal. Did you find a soultion to your problem? What did you do?

2000 Ranger (Trailhead)
104K miles
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RTREV64

 

Extremejv, it sounds like your speed sensor, located atop the rear differential, is acting out, as the speed-o uses it's output to register speed.

If you have a ABS light on, or if you have cruise control & it's acting up by dropping out, or won't set or hold set speed, those are additional clues something is amiss with that pesky speed sensor, which is a common problem on Rangers.

You might also check it's wiring & electrical connector for looseness, damage, or corrosion in the connectors contacts.

If you don't find anything, have the computer scanned for trouble codes & see if any point to the speed sensor, or just suspect the speed sensor is defective internally & replace it.

They don't cost much & are easy to replace, just one electrical connector & a 10mm fastner & "O" ring seal, holding it in. Torque on the fastner is 25-29 ft/lbs.

Let us know what you find.

 

I replaced it today and I am back to normal.

Thank you very much for the info guys!

JAV

 

OK extremejv, good feed back, good to hear your on the road again!!!!