Octavia MK1 2002 110 Tdi Estate.

 

Fuel guage started registering zero, done it a few times in the past and I have had to clean up the sender winding and remake the contact etc, this time I bought a S/H sender.

 

Before removing the old one I shorted the contacts on the connector expecting to see full guage deflection but nothing, checked the continuity to ground of the brown chassis earth wire, all OK, shorted the purple/black to chassis ground no change, checked voltage to sender on purple/black and found 0.25v where I would have expected 5v.

 

My diagnosis is a instrument panel electronic failure or a severed and barely touching wire (unlikely). The coolant temp guage works OK although sometime showing 10° less than normal but could be that I amusing faster roads during close to zero températures or the thermostat not seating.

 

Anyone had this before? Is a change of instrument panel for a second hand one straightforward? Does it need reprogramming? what about the odometer.

 

Any other possible causes of the problem?

 

Thanking you in advance

You could do a continuity check on the signal wire from the sender to pin 5 of the Blue plug on the speedo.

 

A replacement speedo will involve getting it recoded to your ignition key for the immobiliser, the mileage can be increased with VCDS but not reduced, you need Vagcommander or Vag Tacho to get the PIN number to recode the immobiliser and possibly completely reset the mileage?

Thanks Nigel.

 

I have the speedo out at the moment, found another topic showing how to repair the PCB but mine is a later issue with tiny surface mount components so I wont be resoldering any dry joints.

 

Will do as you say, pin 5 being on which connector, there is one on the left and one on the right.

 

You have confirmed my fears re recoding, immobiliser etc, I think that I even  might cobble up an analogue fuel guage somewhere!!!!!

 

I always knew that when the end came for this vehicle it would be through something electronic requiring me shelling out money to someone with a computer   soon to be 15 years old, I have had it for 11 of them and its now done 310k miles.

 

Someone on the forum with VAGsomething software on their computer read the fault codes for me some years back when I had to replace the airbag module, is this VAGcommander the same thing or main dealer only?

 

I can get a S/H speedo cheaply but its the recoding that would be the problem.

 

Editted, "blue plug" maybe they are different colours, will look in daylight tomorrow.

Edited 14 November, 20169 yr by J.R.

You could also do this test.

 

Measure resistance between pins 5 & 7 of the Blue wiring plug with the sender connected you should see: Full tank Approx 270 ohms, Half full 170 ohms, on reserve level 96 ohms 

Reflowing the solder joints of the connector pins is where I'd start.

Checked the sender before refitting the console, had filled the tank yesterday because I knew I would lose the odometer reading and the resistance was 270k ohms.

 

Refitted the instrument console then crapped myself, no instrument lights no nothing, car immobilised, it would turn and kick on the key but die as soon as it was released, dire straits, I am 50 miles from a Skoda garage here and all garages will shaft you dearly, for a moment I thought the time had come when what I have always known to be inevitable had arrived, I must scrap a perfectly good vehicle for a tiny electrical/electronic fault and through living in a country where there is not a community of owners like the UK

 

Then I realised that I had the key in the ignition but not switched on, I removed the console once again, removed all 3 fuses, then refitted it and the fuses then put the key in the ignition and it started thank the lord!

 

I think the coolant temp guage is now Under-reading, its been idling now for 30 minutes and only just off the stop but I was not sure what position to refit the needle, will go for a drive and decide what to do about that.

 

Not going to remove it and start resoldering, its all tiny surface mount components and my eyes are not what they once were although I did have a lot of electronics experience, I dont want to risk a repeat performance of my angst this morning.

 

I'm happy to buy a second hand instrument console but what will be involved in recoding it, the mileage and the keys? Can this be done by someone on this forum or is it a main dealer job?

 

Would it be possible to fit a KM/H version?

 

Thanks for the support, you guys are a lifeline to me!

The connector isn't a tiny little surface mount component though, is it?  It'll be proper pins through holes if it's anything like a Fabia one of similar era, easily reflowed in the Fabia (See this thread for example).

A secondhand one might be no better than the one you have?

Thanks for the continued support!

 

Yes I can see what you mean re the connector, it does seem plausible, wish I had found that thread when I searched before giving myself angst and grief, the one I found was talking about reflowing résistors.

 

Console refitted, still no fuel guage and the temp guage now has had to have the needle reset to sit at 75° with the ignition off to read half scale (90°) at running temp, another niggle that I can live with but the real biggy is that now I have the airbag warning light remaining illuminated

 

I have replaced the module before, with S/H and luckily nothing needed recoding.

 

So when I get my confidence back I will reflow the connector on all the pins, I am worried though after having the dead display and engine immobilised last time, I have limited Tools and no support here in France, I would be more confident doing it on my next return to the UK.

 

However if anyone can say with confidence the problem I had was the keys being in the ignition or the fuse powering the dash or quite possibly another connector pin issue then I will bite the bullet and tackle it here as it may fail soon.

 

Your views?

 

I am using this community not just for the immense depth of knowledge and experience but also to bolster my confidence (I am usually very confident, sometimes too much) to tackle this and also to prevent me doing something risky.

There was another post recently that their car had suddenly become "immobilised" after disconnecting the speedo, and that turned out to be poor seating of one of the connectors, removed the connectors and refitted it and all came good.

 

I've just got a copy of Vag-Commander and connected it to my car, it read the PIN code and I could alter the mileage if I wanted

I am going to bite the bullet tomorrow and resolder the 2 connectors, if its going to fail I would rather it happen now and through my own efforts than later on a journey.

 

If no improvement then I need to look at coding another instrument cluster, is VAG-commander the same as Vagcom or VCDS? The last time anyone looked at fault codes it was vagcom, I have looked at the forum section on diagnostics which is where the new acronyms came up, so what software will be needed to code another instrument cluster to my existing key, adjust mileage, perhaps get it talking to the airbag module again?

 

I am hoping that the latter is just another contact soldering problem, it would be nice to cure all ills but I will be happy with any improvement or just that it restarts!

You need Vag-Commander to get the PIN access code for your original & replacement speedo unit and adjust the mileage, then with the PIN you can set the replacement speedo to work with your ignition key and the engine ECU using VCDS/Vagcom there is a good guide on the Ross-Tech site http://wiki.ross-tech.com/wiki/index.php/Immobilizer_III_Immobilizer_Swapping_(Instrument_Cluster)

Is Vag-commander the same as Vagcom?

 

What is different about VCDS?

 

Does one do all the the others do or are there 2 or 3 different programs needed for different things?

 

Resoldered the connectors, no improvment, still no temp guage, am thinking that I might get the instrument repaired by Cartronix when I am next in the UK to avoid the recoding etc.

 

That leaves the other problem of the airbag warning light, it happened before and I needed to change the airbag module, I used a second hand one and my gut feeling is that it has failed either due to the repeated instrument console removals or removal of a fuse/disconnecting the battery, or is it possible that it is another instrument console problem?

 

I will get the fault codes read at some time to see if the module is communicating with the ECU which should tell me definitively.

 

When I swopped it out last time for a second hand one it just worked and the light went out, is there any more to it than that? Anything that should be coded or reset?

 

Finally its time for me to at the very least invest in a means of reading the fault codes or if its not too expensive maybe one of the diagnostic programs referred to, how much do they cost and what would you recommend? Not looking to reprogram parameters just to be more self sufficient here in deepest rural France.

 

Thanks again

I don't know what vag commander is but I suspect it isn't the same as vagcom, which is simply the old name for VCDS (Ross-Tech had to change the name to not include v a g , I think at VW group's request).

 

Sorry to hear the re-soldering was fruitless. (:

I don't know what vag commander is but I suspect it isn't the same as vagcom, which is simply the old name for VCDS (Ross-Tech had to change the name to not include v a g , I think at VW group's request).

 

Sorry to hear the re-soldering was fruitless. (:

 

Vag-Commander is totally different to VCDS/Vagcom, with VCDS/Vagcom you can't get the PIN code from the speedo, which you need if your going to swap the speedo units, then when you have the PIN codes you then need VCDS/Vagcom to adapt the replacement speedo to your ignition key & engine ECU

Thankyou for the replys, that all makes sense now!

 

How much is VCDS?

Thankyou for the replys, that all makes sense now!

 

How much is VCDS?

 

You can download the "Lite" version for free from the Ross-Tech site and get a Hex-Can lead from ebay for around £15 but with the lite version, you are limited on what functions you can use, I can't recall if it will allow you to re-code things like the speedo, but it will allow you to clear the airbag light, to get the full functions you need to, either pay Ross-Tech $99 for a licence key or you can buy on ebay a Chinese full working copy for £45 but you can't update it when a new version of VCDS is released

Clear the air bag light or clear the fault code?

 

If its the former then I will use the services of a local Briskoda member offering VAGcom on my next UK visit, there only appears to be one in the whole of France!

Clear the code and so clear the light   With the full version you can also drive the fuel & temp gauges to full scale back to zero and then half way, just to prove the drive motors

Thanks, I am going to visit a garagiste that I know this afternoon, hopefully he will have a fault code reader and maybe the means to clear the code.

 

Having read other threads I think that I created the fault condition by removing fuses or turning on the ignition when the instrument cluster was not working, either a low/no volt code for the airbag control module or no comms between the ECU and cluster, so hopefully the module is OK and it just needs the fault code clearing, I'll report back.