Hello I hope someone might be able to help me with a fuel gauge and speedo drive problem I have. I only recently bought the skoda but the two gauges don't work the speedo doesn't measure distance or speed and the fuel gauge moves up and down when I drive. I have changed the speedo binnacle but still no good.

Cheers Sam

Does your reversing light work?

It may seem an odd question, but the road speed sensor and reversing light switch are next to each other and share a fuse/feed.

Thanks rwbaldwin I will check this out in the morning and report back

When we did richs install a fuse went and the speedo and fuel gauge stopped working, iirc

The fuel beep kept going off tho to i think

Worth a peek tho

I had this problem and it turned out to be the switch in the gearbox

Hi thanks for the quick responses the reversing lights all work. anyone know where this fuse maybe as I have checked all the fuses in the fuse box on the right of the dash.

I still have a problem here I have checked all the fuses the reversing switch. PLEASE HELP !!!

I had same problem in my octavia my 2003. There was no fault codes, and tried to fix problem by changing speedo sensor. Checked also that wiring and fuses were ok.

At last i had to change whole instrument cluster, that fixed the problem..

i had intermittent speedo' problems and it turned out to be the famous "****ty joint soldering" problem.

fixed it myself link

OP has already changed the cluster.

My guess is that there are two faults...

Fuel gauge:

One wire (lilac/black) runs directly from the gauge connector to pin 5 on the blue cluster plug. The other wire runs to the loom behind the cluster. Unless the temperature gauge is also fluctuating, then it is not a problem with the earth point. It could be the wiring or the sender. Check the 2-pin plug that connects to the sender.

Road speed:

The white/blue wire from the roadspeed sensor runs to the black 14-pin connector (pin 9) in the plenum chamber connection box. Check that you have power to the other 2 pins on the sensor connector when the engine is running. It's worth looking in the connection box to check for water ingress/corrosion. On the other side of the connector, the green wire runs to pin 28 on the blue cluster plug. You could have a faulty roadspeed sensor. The worst case is that roadspeed gear in the gearbox has cracked and is spinning on the shaft.

If you post the engine code, I may be able to help further

thankyou Rwbaldwin

I have checked the road speed transducer in the gearbox and it is working. How can I find out my engine code please.

Cheers Sam

Your engine code should be on the options sticker with all the little 3 letter codes, there is one of these stickers in the boot near the spare wheel well and there should be another in your owners manual or service booklet. I think it is the top left code on the sticker and should start with an A.

If you have a 1.8T engine the code is stamped on a lug on the front drivers side corner of the engine block.

Hi Again !!!

I took a picture of a label on the timing belt cover as there wasn't a label in the boot I was sure I had seen one but I think it may of been on one I was going to buy. Hope this will help you rwbaldwin to help me !!!!

Cheers Sam

You have the ALH engine (90hp TDI).

How did you check the roadspeed sensor?

I was able to fit a pulse counter which i use to calibrate taximeters the pulse wire I replaced which runs from the drive up to the speedo head

Are you saying that you popped the pin out of the cluster plug and connected your pulse counter to that pin?

Did you do the test with sensor in place and turning the wheels?

I connected a wire to the white/blue wire on the pulse connector in the gearbox. I have also since testing it ran a wire from the gearbox direct to the speedo white/blue

I connected a wire to the white/blue wire on the pulse connector in the gearbox. I have also since testing it ran a wire from the gearbox direct to the speedo white/blue

That's the wrong connection on the cluster. The roadspeed signal is a green wire at the cluster (pin 28, blue plug). The colour changes in the connection box in the plenum chamber.

Thanks I will check that out

Thank you It worked I connected it to the green wire and I got a speedo

Thank you It worked I connected it to the green wire and I got a speedo

That's good news. I was beginning to think the replacement cluster was duff.

It's worth checking the connection box under the wiper motor for water ingress.

You can do the same trick for the fuel sender. The lilac/black wire runs directly from the gauge connector to pin 5 on the blue cluster plug. The most likely cause is the sender itself. IIRC, the gauge is about £50.

It is accessed by removing the cover under the rear seat. If you have to change it, then open the filler cap and mark the positions of all components before unscrewing the ring that holds the gauge assembly.

Since connecting a new pulse wire to the green on the dash plug the fuel gauge is working fine. Cheers again rwbaldwin

Edited 31 March, 201214 yr by airwaveskoda

Hello

 

I have the same problem, But when i check the connection box in the plenum chamber i can't fins any black connector. But there is a orange connector with a blue and white cable in it. Haven't been able to remove the contact to the speed sensor so i can resistance messure the cable between these two points. But there is no connection between the blue and white cable in the connection box and pin 28 of the instrument cluster blue connector. So i guess this might be the problem.

 

Any one knows where i can find a wiring diagram for a 1998 skoda octavia? I have tha haynes manualk but the wiring diagram in it is a joke.

What is the 3 character engine code from the options label (under the carpet in the boot or in the service log book)?

Sorry i found the black connector now and resistance meassured the green cable from pin 28 of blue contact. That part of the cable is no problem with. Tomorrow i will disasamble the speed sensor contact ans meassure that part of the cable to see if i get any fault there. If i meassure voltage over pin 28 against b- i get 0 V is it possible to meassure anything here or do i need to use a ossiloscope to see the pulses?

 

I do not really want to analyse the signal i just want an indication that the sensor is there. I think i have read somewhere that i should meassure 10 v on the sensor signal ?