erratic speedo / fuel gauge and low fuel beep on every corner

[dannyboy201062]

The speedo on my 03`passat sport TDI, 6 speed 130bhp, AVF engine, started to misbehave , then stopped working altogether. Had a look on the forum, scanned for fault codes....none.., Had a look at the vehicle speed sensor above the driveshaft r/h/s , looked fine, connections were oily from a previous leak / weep so cleaned them up...no joy. Bought a new sensor on the internet "Topran" brand, made in Germany, fitted it , no joy. The speedo does not move at all and the fuel gauge moves up and down giving " Please refuel " warnings on every corner with the audio warning beep.......very annoying. I thought I could shut it up by pulling the instrument cluster fuse......didn`t make any difference. Tried fuse F15 ( instrument cluster ) then tried all the other fuses one by one ... no joy..........I`ll try filling the tank, might shut it up for a while. The NCT ( Irish MOT ) is due soon and it will have to be fixed before that.

Any ideas on a next step ?.......I searched the forum but there doesn`t seem to be any other info apart from change the vehicle speed sensor.

Thanks in advance....................Dannyboy

[dannyboy201062]

Some more trawling through the forum seems to suggest I have an instrument cluster problem. Loads for sale on e-bay so it must be a common problem. A little more research ( and the Hyanes Manual ) suggests there is an immobiliser involved, code insertion and it looks like a dealer only can match the replacement cluster to the car..........recode, correct mileage ect.......it`s getting complicated .
What about removing the cluster, looking for a dry solder joint / redo the soldered joints if any ? and refit..........will I need to recode for that ? If I just fit a replacement cluster with the same part no. is the car driveable to the dealer for recode or will the immobiliser prevent start / driving ?

Any ideas ?

[martin1810]

You are spot on about the problems ahead. The immobiliser is in the dash so if you change the dash you need a good locksmith handy at the same time. Looking for bad connections/faulty solder joints is always worth a try if you are up for it.

[dannyboy201062]

Hi Martin, tks for the advice. I had a go at removing the instrument cluster, wasn`t too difficult. Took apart the cluster ( carefully , front and back off ) to look for damage with a magnifying glass on the circuit board , dry joints, bad connections, all looked fine. All connections are so tiny I don`t think I would dare putting a soldering iron near it anyway. Took down all the numbers I could find on it , reassembled everything and all was as before as expected. Headlight flashers don`t work, I must have disturbed something although was careful reconnecting the stalk connectors. I think I might be in there again anyway. Spoke to a local trusted independent who has a good range of diagonistics..........he didn`t have the capability. Spoke to the service manager of the local dealer, just told told him I has replaced the vehicle speed sensor and the snag details. He didn`t seem to think there was a general problem with instrument clusters. New ones are about 350 Euro he said. As expected, he said he needed to read the codes and to book it in.
I`m toying with the idea of buying a secondhand cluster with a code ( 50 Euro / Pounds on e-bay ? ) and having it in the boot. When he calls me to say I need a new cluster , i`ll ask him to fit it . Don`t know if the dealer will fit a second hand part. If not required I can always sell again on e-bay.

I have a handbrake snag too, you might have some info on that..........I`ll start a new tread on that.

Regards................Dannyboy

[martin1810]

These sort of faults are a pain. I usually resolder every joint and keep my fingers crossed. Sometimes it works, sometimes it don't. Some dealers will fit secondhand parts and some won't. You'll have to ask. You should be abke to find a locksmith that can do it. He will need to read both dashboards and then program the new one. There are other ways but it gets complicated and varies with model etc so having a locksmith handy is probably the best way to go.

[VAGMAN2]

I had a problem identical to this on my previous car (Audi A3 1.9TDI/2000). The problem was that the plastic gearwheel, which drives the speed sender, has disintegrated inside the gearbox. Not what I wanted to find and not what I expected. I was convinced, like you, that it had to be an issue with the instrument cluster. It appeared that the absence of speed input signal in to the cluster also confused the fuel gauge.

The test you can do is to remove the speed sender from the drive pinion (on the gear box). First off try and turn the pinion - you should not be able to turn it (mine span freely). Secondly (with the ignition on) spin the small driver shaft inside the speed sender - you should see the speedo dial move up/down as you spin it (and hence rule out a problem with the cluster/electrical issues).

If the drive pinion spins freely, the drive wheel has gone and the gear box will have to come apart.

Interestingly, my A3 never showed any fault codes either, when it had this issue.

[dannyboy201062]

Tks Martin and Vagman..........gulp !........don`t like the sound of the gearbox problem ! I think I saw something similar when trawling the forum. . Thinking out loud....before the speedo stopped working it was erratic. Sometimes when you were stopped it bounced up and down giving me the "handbrake left on" warning, thinking the car was moving when it wasn`t............would I be right in thinking that would rule out the gearbox pinion and rule in an electrical problem ? Back to the Instrument cluster ......do you need a code with the new cluster or does the Diagonistics software just read the code from the old cluster and then apply it to the replacement cluster ? I still have the option of buying the same part number cluster from e-bay......45 + 23 STG posting to Ireland from the U.K. I`ll see can I source one locally. I`ll try the spin the pinion trick in the meantime before I buy anything.
Tks for the info gents................Dannyboy.

[martin1810]

I suggest you look at the gearbox as per vagman2 suggestion. It is a possibility. You can't replace dash with diagnostic tools. You need dealer tools or specialist tools that some locksmiths have. Google dash replacement, you'll find more info.

[dannyboy201062]

Thanks for info gents.........Took out the sensor and could look in the hole with a torch and mirror.......could see clearly but no obvious toothed wheel. .... Got a long thin bladed screwdriver and poked it in all the way and tried to spin a cog wheel. Couldn`t feel any movement. Tried the same with a long thin scriber......no movement felt either.........sounds promising ( not a gearbox snag ? ) Jacked one wheel off the wheel ramp so I could turn it.......bit of a contortionist.....tying on my back under the car on ramps ( safe) mirror in one hand , other hand turning the wheel while looking into the mirror with a head band torch trained on the mirror.....could see clearly into the sensor hole but could see nothing moving...........perhaps both wheels need to be turned at the same time in the same direction to eliminate the differential. ..........I`ve sourced an instrument cluster locally for 50 STG. I think I`ll go for it and book a slot with the dealer and hope for the best. ..........keep you posted. Let me know if you can think of any better options. Can`t find anybody around who has the re-code capability. ...............Regards .........Dannyboy.

[dannyboy201062]

Booked it into the dealer 9am today....sussed him out previously re me possibly supplying the instrument cluster.... said we don`t really fit secondhand parts but let`s see what wrong with it first. He called me about 11.00a.m. He advised they have checked all the usual suspects......speed sensor ( I had replaced that already ) sensor toothed ring was rotating o.k. They checked this by disconnecting the driveshaft, removing the flange and sideplate from the gearbox, all looked good. there was an open circuit on one of the sender wires to instrument cluster. Found broken at the bulkhead.......repaired , speedo and ferratic fuel
guage fixed, new o-ring on gearbox side plate and a litre of gear oil. Car ready @ 4pm. .........380 Euro ! Pricy but I suppose it could have been worse .......to pass the NCT ( Irish MOT ) I need now to replace the l/h driveshaft boot and improve the handbrake. I got good info on the forum re handbrake fix and the drive shaft boot job appears to be straightforward.
Tks for all the help............Dannyboy.