Vag Com shows a LOW KEY SIGNAL fault when I scan my year 2000 Oct Mk1 Tdi 110. Half the time when I put the key in the Immob Light flashes and the car will not start. The problem is the same with the sapre key which is only 1 year old. I have replace relay 109 but no improvement.

I have located a spare key barrel with transponder sensor attached but cannot figure out how to seperate the two. Also i was told that if the sensor is replaced then it has to be re-coded to the car. Has anyone come accross this and how to fix / recode etc?

Thanks

The read coil is an integral part of the ignition lock barrel and cannot be separated. What you need to do is replace the wiring loom from the read coil to the back of the dash panel. The loom is a twisted pair of a black and a green wire, with a plug on one end for the read coil and terminals on the other end that plug into one of the dash multi plugs.

The trickiest part is removing the old wires from the dash multi plug. The loom will cost around £6.

Looked at a similar age OCTY yesterday and traced the black and green twisted pair cables from the Immo transponder back to the multi pin plug on Instrument Panel. DOn't see an easy way to change this...........so I am thinking of using a twisted pair (screened belden / other) and soldering to the existing wires near each end......

DO you know if larger diameter wires will sort this problem of Low Signal?

I believe the wires are twisted to prevent interference for other circuits running parallel inside the wiring harness.

Larger wires will not solve the problem. Unless the wires are damaged, the volt drop is negligible.

You need to replace the barrel and sensor coil. Get the dealer to order a replacement which matches your existing keys.

Darn - was kinda hoping that a cable would fix the problem. Deal (in Ireland) wants 130 euro for the parts and said the new transponder would have to be coded to the car - so another 75~100 for this as I do not have the 4-digit IMMO code to get into programming mode for my car.:confused:

I've only changed one of these once. I provided the info from the key tag and asked for a new barrel to match (includes the sensor coil). No new keys and no recoding

I might call a Skoda dealer in Northern Ireland and see if they do a better deal than the local guys in Dublin. Thanks

Replace the loom first, it's a lot cheaper. The part number is Part number is 1U0971809. If you don't feel confident removing the wires from the dash multi plug, you could try soldering at that end. If it works you've saved yourself alot of money, if not you've only lost £6. I've cured a few Octavias with this problem in this way - using the official Skoda fix.

It's worth a try - I will get the part over the weekend and have a go. THANKS:)

I've often wondered what could go wrong with a simple 2 wire loom.

Anybody any ideas?

My own thoughts are perhaps maybe it's not the loom itself, but poor contacts at the key/barrel and dash ends. Maybe if the connectors are pushed on/off a few times that would restore better contacts?

I'll find out myself as my own octy is starting to exhibit this behavior...

Regards,

tbxp

Good question....I have no idea why two little wires cause this problem - however I presume they are twisted to minimise cross-talk singals / interference from adjacent parts of the wiring loom...similar to the principle used in CAT 5 Data Cables. I know in HVAC control systems they use a cable screened in aluminium foil to prevent interference with the controls.