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Discussion Starter #1
Howdy,


2007 ST, my speedometer has been intermittent for about six months. Upon initial start up and movement there is no speed registered but the odometer still works. Sometimes it will start to register above (estimated) 30mph but is not accurate.

The first few times it happened I was able to get it working by turning the car off for >10seconds then moving the key to "on" and letting the car go through it's entire power up light/chime dance.

Not sure if temp is a factor, it is hot here from May onwards, little to no moisture either.


Also looking for a trusted source for a factory service/repair manual (not Chilton's or aftermarket)



Thanks


Chris
 

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Moved to "General Technical Chat". Have you taken the speedometer out for any reason in the past? I know sometimes it will act like this when the connection is not secure in the back.
 

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Discussion Starter #3
Never touched the dash. Never been any reason to get back there.

Cheers


Chris
 

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"""Also looking for a trusted source for a factory service/repair manual """

Ebay my friend is YOUR friend

I only found a printed wiring diagram manual and a DVD

type this into Ebay search

2007 Ford Focus Workshop manual


Then you can get what you want from Helm but at full retain cost
 

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+1 on using eBay for the factory service books, plenty of dealerships that closed over the last few years, plus the fact our cars are getting older and out of warranty so they are starting to liquidate the older books. I've gotten books for my 95 Caprice, 93 and 98 Escorts, 06 Focus, and my old 93 Cavalier off of eBay, most of the sets I was able to get for under $50. Be sure you get both books as one covers mechanical and body and the 2nd covers electrical wiring issues.

One thing however is the vehicle specific books do not cover emissions related issues, so if you want to be able to have a factory insight in diagnosing those you will have to get the Powertrain Control / Emissions Diagnosis book for the model year of your car, as Ford has one PCED book for many models of vehicles, though they seem to have separate ones for hybrid and diesels vehicles so watch out for that.
 

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If it is being intermittent, I would look at a possibility of a ground wire being loose/broken. Not exactly sure which one would be loose, but that's the adventure in working on vehicles lol.
 

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Vehicle speed is sent over the data bus wires. There is no 'ground' in the normal sense.

Ignition interference is the most common cause of a sporadic speedo. This can be a damaged Ignition Resistor, damaged spark plug / ignition coil.
The other option is a damaged/dirty Vehicle Speed Sensor. Sometimes the collected metals on the sensor can inhibit it from generating a reliable voltage.
 

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Discussion Starter #8
Ok fleabay it is for the FSM, thanks.


I just had the sparkplugs replaced by the local dealer (I didn't want to deal with the possibility of siezed/stripped threads) and they didn't mention any coil problems.

She runs like a top, mpg never varies much and I've never noticed a misfire.

I'm guessing the VSS is on the transmission? Is it an obvious plug? Should I go from up top through the engine bay or from underneath?

Thanks much for the replies!

Cheers


Chris
 

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Ok fleabay it is for the FSM, thanks.


I just had the sparkplugs replaced by the local dealer (I didn't want to deal with the possibility of siezed/stripped threads) and they didn't mention any coil problems.

She runs like a top, mpg never varies much and I've never noticed a misfire.

I'm guessing the VSS is on the transmission? Is it an obvious plug? Should I go from up top through the engine bay or from underneath?

Thanks much for the replies!

Cheers


Chris
Should've done those plugs yourself, they're wicked easy. Only takes about 15 minutes to do ?
 

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Discussion Starter #10
Well if I wasn't down to my last working vehicle (two down for repairs) and Ford didn't have a rep for seized sparkplugs in their aluminum heads, I would have. They are RIGHT there when the hood is open.

This way if the dealer did it and they stripped out, its all their dime and I get a loaner.

Worth it for the peace of mind of being able to get to work on Monday.

Normally do all my own stuff, the other two are eating up funds available for big repairs.


Cheers

Chris
 
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