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Another fiesta speedo fault


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Hi , We have a 03 1.25 fiesta non abs run around that has just had it's head gasket done. on the day after we have lost the mile's display  and the eml is on + the speedo jumps up to and stays at 5mph when the ignition is on or running and driving .

iv'e changed the vss and also checked the vss wiring but the fault continues.  Dose anyone have any ideas which way to go next ? could it be a pcb fault inside the cluster?

Thanks in advance .:-)

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12 hours ago, Barry67 said:

and the eml is on +

You need a diagnostic scanner to find out why the eml is on.

It could be the cluster, but without the codes, it is just guessing in the dark.

A system like Forscan is best for this sort of problem, it can read codes in the cluster, and do a self test on the cluster.

Forscan is a powerful Ford specific system. Cost £15.00 for the interface. Needs a computer of some sort. (COM port, USB, bluetooth or WiFi interfaces available). Not as simple as the self contained OBD2 scanner. You will find a lot about ELM327 & Forscan on this site, which together provide a very comprehensive diagnosis & maintenance tool. Post here if you want more info. James (jeebowhite) has done a nice guide: http://www.fordownersclub.com/forums/applications/core/interface/file/attachment.php?id=21196

For an ELM327 adapter, see

The Forscan programme is free and you can get it from

Note: Simply reading the codes can do no harm, and does not change anything. Just do not reset the codes (and you would have to ask the scanner to do this) if you are going to take the car to a garage.


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2 hours ago, Barry67 said:

i have a old laptop just for this type of thing

The Windows version is free, and quite a bit more powerful then the IOS or Android versions, and is fine on XP or later.

Stick with the USB (or even serial port) ELM if possible, wireless ones vary a lot in quality.

I am not sure how the VSS is connected. I suspect it is wired in to the pcm (aka ECU or ECM), then the Cluster gets the speed data over the CAN bus. So if the DTC is in the pcm (& Forscan will tell you where the DTC is), it may still be the sensor or wiring. But if there are CAN bus errors reported, or if the DTC is in the Cluster, then the fault may be in the CAN bus wiring, or in the Cluster PCB.

These Cluster PCBs are usually repairable for a relatively modest cost, if you can afford the time without a car.

Good point from Dave, below. The importance of DIY diagnostics is even greater with older cars. Once in the garage, diagnostic charges can rack up before you even make a decision about repair or scrap, and it makes the decision harder.

I am not sure Forscan is much use on an Escort, though I could be wrong! But If you get another Ford, or repiar the Fiesta, then the system will surely come in useful in the future.

Edited by Tdci-Peter
Add Note about repair vs scrap!
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Remember its a 2003 fiesta. so weigh up potential costs of fixing (inc all parts and labour etc v the value of the car. absolutely no point throwing money fault chasing at that particular car so i'd possibly bear that in mind. Good luck with it though, hope it turns out to be an economical and low cost repair.

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Cheer's guy's. There will be no garage bills as i do all my own work.   just got to wait for the adapter to arrive so i can get stuck into it .:smile:

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Hi , just picked the adapter up from the post office and have the laptop in the car with forcom installed and all ready to go .

but all i'm getting is no elm found check connections . have done this several times but still getting the same result .


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10 hours ago, Barry67 said:

all i'm getting is no elm found check connections

That is annoying! Usually this connection to the ELM goes ok.

I am assuming you are using the USB version of the ELM.

When the ELM is plugged in to the laptop, with or without Forscan up & running, is there any reaction from the laptop - messages, sounds, windows popping up? (Try this with the ELM plugged in to the car diagnostic socket if there is no reaction with it unplugged. I am not sure whether the ELM gets its power from the car, or from the USB port.)

When Windows detects a USB device being plugged in, if it recognises the device and has used it before, it just loads the relevant driver. But with a new device, it should come up with a message box saying something like: "USB device found, searching for driver". If it can find a suitable driver then it loads it and should say something like: "USB device ready".

If it can not find a driver it will usually ask if you have a CD, or want to search the Internet for a driver. Usually no additional driver is needed, but sometimes a relevant USB device driver is needed, I think the tunnelrat ELM uses a Silicon Labs driver.

If there is no reaction, do you have some other USB device (USB flash drive, printer, camera etc.) with a USB connection, that you can plug in to the USB port on the laptop to test it? Laptop ports are a bit susceptible to damage.

The only way I know to check whether a device has been recognised, is to use the Microsoft Device Manager utility. This is rather hidden away, on my XP system it is under Control Panel, Administrative Tools, Computer Management, Device Manager. For more on Device Manager, see :http://pcsupport.about.com/od/tipstricks/f/finddevmngr.htm

Once Device Manger loads, it should have a line for Universal Serial Bus Controllers. Click on the "+" by this to show all detected devices. A line there should appear for the ELM, and diappear if the ELM is unplugged.

If your USB port is ok, and the ELM is not recognised by Windows (does not appear in Device Manager, nor ask for a driver), then you will probably need to contact the supplier.


If the ELM is being recognised by Windows, but Forscan is not finding it, check this:

Again, in Device Manager, look for a line called "Ports (COM & LPT)" or Serial Ports, or something similar.

Open this line, see if there is an entry that appears when the ELM is connected to the laptop, and vanishes when unplugged. It may be COM17, or something like that.

Run Forscan, use the Settings menu (the gear wheel symbol). Enter the COM port number from Device Manger in the COM Port box, and re-try a connection. Though the Auto setting usually works ok.





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Cheers Peter,

Yes usb adapter .  the laptops ok have tested it and have spent 4 hr's trying to get it to work downloading drivers ect  for it and still no joy . just keep getting code 10. even had my computer wiz mate hear and came to the conclusion it must be the lead at fault :unsure:

going to have another go tomorrow with fresh eyes .:smile:

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5 hours ago, Barry67 said:

just keep getting code 10.

I am not sure where code 10 comes from.

If I connect to my ELM (with Ignition Off), I get:

[22:38:12.546] Connection to adapter has been established on COM1
[22:38:12.546] Adapter:  ELM327 v1.5
[22:39:15.984] Unable to connect to vehicle. Please make sure the ignition key is ON and try again

If I try with no ELM, or with no power to ELM (not plugged in to car socket), I get:

 [22:39:16.000] No ELM found. Please check connection and try again.


Do any LEDs light on the ELM? When I power up my ELM (plug in to car), Yellow LEDs sequence along, and the red LED lights. (Regardless of whether connected to computer, or not). If this does not happen there may be a fuse in the car that powers the diagnostic connector, that has gone.

Have you managed to load the Microsoft Device Manager?

If on plugging the ELM into the laptop USB socket, there is no request for a device driver, and no change in the devices listed under Device Manager, and the ELM power LED is on, then, as you say, the ELM must be faulty.

This sort of major fault is quite rare, normally they work, but some poor quality Chinese clones work badly.



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Yes. we're in :biggrin: Cheer's again Peter.

Now iv'e a list of fault code's.

pcm  p0693-60

pcm  p0646-60

pcm  p0036-fo

pcm  p1000-70

obd11  p0036-c

ic  u2200-63

ic  u2197-63

 ic  u2510-63

ic  u1262-63




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50 minutes ago, Barry67 said:

Yes. we're in

Do you know what the problem was? Might help me to assist others.

I will try to have a closer look at those codes later, but at a glance, from the number of modules involved, it certainly looks like a fairly classic CAN bus communications problem, most likely in or near the IC.


There is a simple test that can be done on the HS-CAN bus:

There is no need to disconnect the battery. At least on my car the CAN bus went off about 30 sec after turning the ignition off. The PCM stays active for a while, I can hear it testing the EGR valve, and maybe doing other things, then it powers down and the bus goes dead. You can check with a voltmeter, CAN lines (6-14 in diagnostic connector) will be 1v to 3v when active, 0v when off.

Stick a couple of suitable probes (un-bent paper clips can work quite well) in the diagnostic connector pins 6-14, put a DMM across the pair on voltage range, turn ignition on, note reading, turn ignition off, wait till voltage drops to zero (+/- 1 or 2 mV), switch to resistance range to check for 60 ohms.

If 60 ohms, try tapping and moving various suspects, eg the fascia around the IC, the connector by the front door sill, the connector in the engine bay fuse box, and maybe the PCM. Look for any deviations. (IC = Instrument Cluster)

If not 60 ohms, disconnect the engine bay fuse box big connector, see if reading goes up. If it does, then IC is the fault, if not then PCM may be the fault.


The HS-CAN bus goes from PCM to IC via the underbonnet modules like ABS & TCM.

As both the PCM and the IC (Cluster) contain 120 ohm resistors between the two CAN lines, it is quite easy to detect whether all joints are intact at least up to these resistors. If the bus is intact, the two 120 ohm resistors in parallel make 60 ohms. There are several connectors in this chain. And both resistors are vital to proper data transfer, so problems in the IC could cause those comms failures.

This will not test other modules on the bus, nor internal faults in IC or PCM (apart from the 120 ohm resistors)

As whatever fault you have seems to be intermittent, it is worth often repeating this 60ohm test.

(Also the MS-CAN bus goes from IC to BCM (aka GEM), via body related modules, and can be tested the same way, but on pins 3 & 11 on the diagnostic connector.)


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Hi, every thing working as normal when ign switched off egr ect.       put the meter on 6-14 pins and i'm getting 1.5v with the ign off and 12.5 on .

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1 hour ago, Barry67 said:

put the meter on 6-14 pins and i'm getting 1.5v with the ign off and 12.5 on .

I just looked back to the 1st post, I was forgetting this is an 03 Fiesta. Some of what I said about the CAN bus may not be right, for this car.

When Forscan connects to the car, does it come up with a protocol message, like "Protcol: SAE J1850", or "ISO15765 CAN"?

Those voltages on the diagnostic connector don't look much like CAN bus voltage levels to me.



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51 minutes ago, Tdci-Peter said:


When Forscan connects to the car, does it come up with a protocol message, like "Protcol: SAE J1850", or "ISO157



just popped out and plugged it back in to check and couldn't see any of those ^^ .

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3 hours ago, Barry67 said:

put the meter on 6-14 pins and i'm getting 1.5v with the ign off and 12.5 on

Those are very odd voltages for a CAN bus. If pins 6 & 14 are fitted (and used) in the diagnostic connector, then they will be a CAN bus, it is part of the OBD2 international standard.

(I asked the question about protocols to try to confirm if this vehicle uses CAN bus, I do not have any wiring info for it, unfortunately. From the DTC list, it does have a CAN bus, but it is just possible that it is not used for the diagnostic connection, there are other methods allowed)

I would expect 1 or 2 volts with ignition on, falling to 0v when the pcm powers down, which is usually up to a minute after ignition off. Check you are reading the pin numbering the right way round, perhaps?

If there is a CAN bus on pins 6 & 14, then the 60 ohm resistance test is still valid (above), but it will only work if the bus powers down to 0v.

The list of errors you got from the car was:

P0693 Cooling Fan 2 Relay Control Circuit Low

P0646 A/C Clutch Relay Control Circuit Low

P0036 - HO2S Heater Control Circuit Bank 1 Sensor 2

P1000 FORD - On Board Diagnostic System Readiness Test Not Complete

U2200 - Invalid data for Odometer

U2197 - Invalid ‘Vehicle Speed’ data

U2510 - CAN invalid data for security maturity

U1262 - Data Circuit Message: PCM Received Signal for Fault on Bus Circuit

B1881 - Safetybelt Passenger Retractor Circuit Failure

B1316 - battery saver relay coil circuit short to ground

Either there is an impressive number of unrelated faults on the car (very unlikely!), or there is a communications problem between modules. It is a fairly typical example of comms error codes.

Next problem is finding the fault. IC is a likely culprit. These can be sent away for repair for under £100 (search eBay or Google for cluster repairs). That is a better option than a very expensive new one, or a possibly dodgy used one that will have to be coded to match the car.

(I did repair my Focus IC for £0.00, but I have decent soldering equipment, and electronics experience!)

But there are other possibilities: There will be one or more connectors in the CAN bus lines from pcm to IC, one near the kick panel in the passenger footwell, I hear, & maybe one in or near the engine bay fuse or relay box.

Does tapping the fascia around the IC make the fault list any different? That would indicate the IC.

The 60 ohm resistance test remains the simplest way to test for certain, common faults on the CAN bus.

The green pins in the pic below are the CAN bus pins (6 & 14).


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Will check plugs today  , yes i'm checking the correct pins but the plugs upside down in the car.:smile:


My mate installed the driver's on my laptop in the end at his computer shop as i went round in circles and blue screened it some how.:blush:

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Tested the pin outs this evening and couldn't get a  ohm reading from them . went though the plugs around the car this afternoon and found a few green pins in a couple of them.

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3 hours ago, Barry67 said:

found a few green pins in a couple of them

I guess your green pins are corrosion, not related to the green pins on the connector in my drawing abovebiggrin.png

Meths or Iso-propyl alchohol can be used to clean connectors, though both are flammable of course!

Contact cleaner might help a bit, but it only makes a small difference, and often not for very long. But at least if it changes anything (keep running the diagnostic checks), it give a clue as to the location of the fault. Just plugging out & in will clear light corrosion.

The lack of CAN bus voltages & resistance is a bit odd. Usually if the pins are present, they should be CAN. Perhaps they are present but not connected to anything. Do the measured voltages drift around, with a high ohms reading?

It may be that if all obvious possibilities (like connectors & fuses) are eliminated, you will have to assume it is IC, and replace it, or send it away for repair. I hate doing things like that without some more direct evidence, but it is the way most garages work, though.


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Didn't get chance as planned to have a look at the car today as going away for a week in the morning ,so had the shopping and packing thing to do so car's on hold till i'm back.

will update when i return .:smile:

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  • 2 weeks later...

Well i'm back from my little break away. and had a few hr's on it this morning,  a friend of mine had one they were gong to scrap when i was away so they kindly saved the ecu. alarm module . dash and key with the reader . fitted all this to the car and turned the ignition on and i now have my mileage counter back  but now the car now cuts out and wont idle . i can keep it running by tickling the throttle  but that's it .  but one thing i have eliminated it is not a wiring fault. .:smile: going to have another play with it later.

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2 hours ago, Barry67 said:

i now have my mileage counter back  but now the car now cuts out and wont idle . i can keep it running by tickling the throttle

There is a procedure to reset the throttle setting on some engines.



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1 hour ago, Barry67 said:

replaced the old ecu and accompanying bits and pieces and it runs fine and idles

Does the "bits & pieces" include the IC?

Or have you managed to get it working with the replacement IC & original ECU?

If the original speedo & odometer faults have gone away with all the original parts back, it looks like an intermittent fault has been cured, for now at least, by all the disturbance.

If the IC is a replacement, it would be possibly useful to know, for someone, that this unit can be replaced on a 03 Fiesta. There is always a lot of uncertainty about which parts can be replaced without re-programming.

Glad to hear it is working!

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