Hi all, Newbie here.

i've got a Focus 1.6 Zetec, 51 plate.

Ok, I'll start by mentioning that ever since i have owned the car (2 years now) i have had an issue with the speedo. on occasion it would stop working for a few seconds, then in winter it would do it more frequently and for longer periods. although it is a fault it has never really been a problem and has never turned the engine warning light on.

However, this morning i looked down to see that my speedo was up to it's old tricks again, only this time i had the engine warning light on as well.

So after reading this forum i found that i could do a self diagnostic by holding down the reset button on the speedo and turning the engine on.

I cycled through the tests and have got these DTC codes from it:

D123 Invalid or Missing Data for Odometer

D041 Invalid or Missing Data for Vehicle Speed

9318 Battery Voltage Low

I have also been told by a friend that it is possible that an issue with the alternator/low battery voltage could cause my speedo to do this.

so all in all these errors seem to hit the nail on the head, but as my speedo is now working again should the engine warning light have turned off or do i have to reset it. or possibly a new battery might help?

any help appreciated, thanks

Doug

Oh, i forgot to mention that when the speedo stops working the cars tends to kangaroo a bit in low gears, and the power drops (electric), I only noticed this because the volume of my stereo drops whenever the speedo fails, so that could explain the low battery voltage error.

It sounds like the speed sensor (located on gearbox) is at fault. The cylinder head temp sensor can cause this too. It's located between the spark plugs, and the cable causes interference when it comes in contact with the spark plug ht cables.

i would say speed sensor happens a lot :)

Thanks for the replies guy's,

would you say that the engine warning light should have gone out though? now that the speedo is working again (until next time )

is replacing the speed sensor an easy job?

Engine How-to - Replace a VSS (Un-common type).pdf This should give you an idea of what is involved, see attached.

Engine How-to - Replace a VSS (Un-common type).pdf This should give you an idea of what is involved, see attached.

have to disagree on this one the stereo volume drops and you have a battery dtcv code ide be having the battery checked to see if it has a faulty cell therefore not charging correctly also check its a silver calcium or double calcium lead battery the ford smart charge has a sensor in it that can tell if a battery has double calcium or silver in the electrodes if it hasnt you can have all sorts of issues forget the vss and have the battery checked and tested for free in most garages if the battery is ok then go for the vss

i would say vss

The reason the radio decreases is because the VSS sends a signal to the ECU which in turn sends a control signal to the radio's volume control circuit, the idea being the faster the car goes the more road noise etc; is generated so the radios volume is turned up to compensate, and vise-versa.

i would say vss

The reason the radio decreases is because the VSS sends a signal to the ECU which in turn sends a control signal to the radio's volume control circuit, the idea being the faster the car goes the more road noise etc; is generated so the radios volume is turned up to compensate, and vise-versa.

But if it was the ECU controlling the volume then I wouldn't have got the low battery voltage error code would I?

I think i will probably check the battery first anyway, as that is definitely going to be the easier/cheaper option for me to sort.

but saying that i have always suspected the VSS anyway, so wouldn't be surprised if it is that.

thanks for the help everyone.

if anyone has any more suggestions they are more than welcome.

Hi doug , I have exactly the same issues . The car hunts at 2200rpm hence kangaroo in low gears . As regards the alternator , I tested the charge with and without the smart charge connected ..... With it connected the voltage would fluctuate 14.7 v no load , 14.3 v under load and disconnected maintains 13.8v .

I plugged in a alternator tester into the cigarette lighter , ikangerooing seems to reduce but for some reason after a period of time the alt voltage rises and the problems occur .... Did you have the same issue? .

Also is anybody aware of the earth/ neutral connection for the sensor and smart charge circuit in case it is an earthing issue ?

Cheers

The earth I believe is connected directly to the gearbox?

I say it might just be a faulty cluster. It's a issue that effects everything on the car. Engine going limp, cluster displaying nothing.

I changed the cluster today with a refurbished unit (The unit obliviously wasn't programmed with correct mileage etc..,). Symptoms were exactly the same.

Had an auto electrician look at it, as he had an IDS system, he assures me it is more than likely the target the sensor picks up in the gearbox..... umm as far as i'm aware there is no target as such, but what exactly does it pick up ??. I don't want to put in a refurbished box if we are barking up the wrong tree.

Also this does not explain the rise of mph when the car is revved stationary.

Any ideas ??

Faulty sensor if it not the cluster then.

Things checked/changed so far:

-VSS sensor, changed with brand new ford genuine part.

-Cleaned existing cluster with contact cleaner

-Swapped cluster

-Parted every electrical plug/connector and cleaned, proven for continuity, S/C, E/F and high resistance.

-Tested alternator, found 13.8v with smart charge disconnected, with smart charge connected between 14.02-14.7V.

-Changed battery with approved CA type .

-Re-routed head temp sensor cabling away from HT leads and coil pack.

Can anyone tell me , what is else is part of the smart charge/VSS circuit? . Is there a earth point ? .Also what does the sensor pickup in the gearbox?. Does the late 2004 Mk2 Focuses have Wheel speed sensors aswell as part of the ABS .

Cheers

Mk2 use abs to read speed. Have you checked if it might be a faulty abs system. Is the problem you having the speed turn off. Check the abs

ABS wasnt used for the speed monitoring until MK2, it works on the premise of the car taking the reading of all 4 wheels and ensuring they all report the same speed. Any wheel that indicates less or more than the noted speed from the other 3 wheels would report an ABS error.