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        General >> Problems >> o/d light comes on
        
(Message started by: lleewar on Jul 17^th, 2009, 8:28pm)

Title: o/d light comes on
Post by lleewar on Jul 17^th, 2009, 8:28pm

Hi All need advice. While driving on the a12, the overdrive light comes flashing on on the dashboard and top gear is lost. Stopped car to reset and carried on but that only is a temporary fix. What is happening and what is the fix..Hope it's not bad and not expensive :'(

Title: Re: o/d light comes on
Post by Highlander on Jul 17^th, 2009, 8:33pm

Hello and welcome to the site :)

Have a read at the following

http://www.fordscorpio.co.uk/odlight.htm

Which engine is it you have?

Does your speedometer work properly?

Check the gearbox oil level and condition using the correct procedure :

http://www.fordscorpio.co.uk/autogearbox.htm

A gearbox oil and filter change has been known to solve this ;)

Clean the MAF

http://www.fordscorpio.co.uk/cleanmaf.htm

On OBD scan would be very helpful, where are you located? someone may be able to do one for you.

Possibly a wiring loom issue but check the above first before we look at that.

Of course it may just be that your gearbox has had enough, it will be at least 11 years old after all ;)

Worst scenario = another gearbox/loom

A new gearbox is probably not viable now but second hand ones can still be picked up fairly cheaply if you can get someone to fit it ;)

Title: Re: o/d light comes on
Post by wojtekor on Jul 17^th, 2009, 8:39pm

95% chance that it's the gearbox wiring loom...

Title: Re: o/d light comes on
Post by Highlander on Jul 17^th, 2009, 8:41pm

on 07/17/09 at 20:39:02, wojtekor wrote:

95% chance that it's the gearbox wiring loom...

100% chance thats a guess! ;D

Not the fuseboxes this time?? ;)

Title: Re: o/d light comes on
Post by lleewar on Jul 17^th, 2009, 9:00pm

Hi Should have given you more info before starting. It.s a 1995 2.0 Ultima, has new and clean MAF, speedo sometimes erratic and not showing correct speed, oil level OK but not bright red, more a murky light brown with no rancid smell.

Title: Re: o/d light comes on
Post by lleewar on Jul 17^th, 2009, 9:01pm

I am in not so sunny at the moment Clacton

Title: Re: o/d light comes on
Post by tlundkvi on Jul 17^th, 2009, 9:21pm

on 07/17/09 at 21:00:17, lleewar wrote:

If there is a problem with the speedo showing erratic readings, it's likely it's only the VSS that is broken or it's drive pinion is worn (separate finis). I have a bad VSS, and o/d flashes every now and then, and gearbox smoothness is lost. I have a 24V & A4LDE though which is more dependent on the VSS, but anyway I'd check that out. It's one of the easiest things you can fix & replace on a scorpio. Is the VSS problem you have simultaneous with loss of 4th?

Title: Re: o/d light comes on
Post by wojtekor on Jul 17^th, 2009, 9:38pm

on 07/17/09 at 20:41:34, Highlander wrote:

100% chance thats a guess! ;D

Not the fuseboxes this time?? ;)

not a guess, statistically supported theory :)

i'm keeping the fuseboxes for later. ;)

although if you're saying that the speedo missreads then tlundkvi's theory is most likely right...

Title: Re: o/d light comes on
Post by Highlander on Jul 17^th, 2009, 10:09pm

Yep, sounds like it may be the VSS

lleewar the speed sensor not only provides the speedo reading but is used to control the auto gearbox such as gearchanges etc.

Its a simple replacement, one bolt and a multiplug connector.

you can reach it from under the car
http://i41.tinypic.com/qxksc3.jpg

or if it raining you can get to it from above ;)

This is the view with the gear selector removed, VSS is directly below.
http://i31.tinypic.com/23k507.jpg

Title: Re: o/d light comes on
Post by lleewar on Jul 17^th, 2009, 10:13pm

Have lost 4th a few times while on motorways and revs have leapt. Have to let foot off the pedal for it to engage( possibly third) and when it does and u put the foot down again, it races up the revs again begging to change.

Title: Re: o/d light comes on
Post by tlundkvi on Jul 18^th, 2009, 5:48am

on 07/17/09 at 22:13:26, lleewar wrote:

Is the speedo erratic only in high speed?

Title: Re: o/d light comes on
Post by lleewar on Jul 18^th, 2009, 3:29pm

Sorry for late reply. It is errastic mostly in the higher speeds.When slowing down to say a roundabout and pulling away again the speedo continues not to register the right speed. Also noticed that the cruise control does not work properly. Sometimes it will set ok and cruise ok but while in cruise the speed gets erratic and the revs move up and down, feels like its misfiring or missing.

Title: Re: o/d light comes on
Post by Highlander on Jul 18^th, 2009, 6:42pm

VSS definitely then ;)

Title: Re: o/d light comes on
Post by lleewar on Jul 19^th, 2009, 12:46am

Thanks everyone for the advice. Will purchase a new vss and will post the results. This site and forum is a great source of info and I will definitely call on the experts again if i get any more problems :)

Title: Re: o/d light comes on
Post by tlundkvi on Jul 19^th, 2009, 7:20am

on 07/19/09 at 00:46:34, lleewar wrote:

It's quite expensive though around £100 for all three parts (VSS+Pininon+clip), so it may be worth looking for a 2nd hand part. And the pinion should be from the same model, but that one is much less if you need to get a new one.

Title: Re: o/d light comes on
Post by lleewar on Jul 25^th, 2009, 2:56pm

Have purchased a secondhand vss and put it in. Checked with ford that it was the right one and they told me it was used in a number of fords, seirra, transit etc. Body of it is different to my one . Does this make any difference?????????? Thanks for the pics Highlander. Now the cruise control seems to work but the speedo seems to show about 10 miles over actual speed and unusually gear changes and kickdown are much better.

Title: Re: o/d light comes on
Post by tlundkvi on Jul 25^th, 2009, 4:26pm

on 07/25/09 at 14:56:33, lleewar wrote:

Appearance doesn't make any difference. The first scorpios used a metallic housing type, and the newer ones use one with a plastic housing. Both are interchangable.

You have got the wrong number of teeth in the driver pinion of your VSS (detachable separately). You need to get the pinion from the exact same model. Yours has too few teeth (resulting in too many revolutions per distance driven => higher speed than actual), which indicates you got the replacement from a 24V, if the donor was a scorpio.

If the other problems went away, your VSS was definitely broken somehow.

Title: Re: o/d light comes on
Post by Highlander on Jul 26^th, 2009, 9:29pm

Hmmm I think he has the correct one.

Is your actual speed from the sat nav?

The Scorpio speedo should show roughly 10% over actual speed (Ford designed them that way)

on 07/25/09 at 14:56:33, lleewar wrote:

and unusually gear changes and kickdown are much better.

Thats not a bad thing :)

So after worrying about it being a new gearbox you fixed it yourself for a few quid ;D

Title: Re: o/d light comes on
Post by lleewar on Jul 27^th, 2009, 4:55pm

Hi There . Have removed the secondhand vss to check the number of teeth. The pinion supplied had 19 teeth and my original, yes original after 145000 miles, has 21 teeth so I swapped them over. Will relay the results back to you after a couple of long runs.

Title: Re: o/d light comes on
Post by Highlander on Jul 27^th, 2009, 6:54pm

The 21 teeth is correct for the 2.0 16v

your 19 teeth one is for a 2.3

was your "actual speed" reading from the satnav??

Title: Re: o/d light comes on
Post by tlundkvi on Jul 27^th, 2009, 8:05pm

Did a test for fun. Here are the results (km/h):

Car needle = N, Dash diagnistic mode = D, GPS = G

C 80 105 120 140
G 76 100 115 134
D 76 99 115 133/134

Some small jumping on the diagnostic mode, Car is a 24V with original VSS pinion. My conclusion: The dash diagnostics is pretty accurate, it showed although sometimes jumping exactly the same speed as my GPS (Garmin nüvi 200).

Second conclusion: The scorp knows it's speed accurately, it just shows the +5% value for the driver while basing decisions on accurate values.

But this was on my car. Drove a 15km spin on a nearby almost empty motorway with varying speed.

A speed mod would be to put a small resistor regulating (lowering) the voltage to the needle, someone with a loose dash might be able to do this.

Title: Re: o/d light comes on
Post by lleewar on Aug 2^nd, 2009, 12:55pm

Hi guys Just to let you know that all is well with the vss. :) :) Since changing the pinions over, the car now shows the correct speed coupled with the rev counter changes. I now actually know what speed I am doing without the need to look at the satnav. Thanks very much for your invaluable help.

Title: Re: o/d light comes on
Post by lleewar on Aug 6^th, 2009, 11:00am

Highlander, this one is for you. Just to let you know that the speedo shows around 6 to 7 miles above what the satnav(TomTom) shows, so your 10% theory matches up.

Title: Re: o/d light comes on
Post by Highlander on Aug 6^th, 2009, 11:02am

Thats the correct 2 litre VSS?

So your 2.3 one was showing a good bit more then?

Title: Re: o/d light comes on
Post by lleewar on Aug 6^th, 2009, 11:29am

Yes up to 20 miles an hour over. The pinion makes a massive difference to speedo readings. Thanks for all of your input, it is very much appreciated.

Title: Re: o/d light comes on
Post by Highlander on Aug 6^th, 2009, 11:41am

I ran around in my 24v for a while with the 2 litre diff fitted and the 24v VSS,

kids thought i was driving everywhere at 120! ;)