As I have had a fair few PMs on this issue and seen a little traffic on the forum I though I'd make up a little guide on what is a fairly old concern.

The symptoms would be a non start, possibly intermittent and the immobilizer light flashing on the dash. This can be for many reasons but this is quite a good cheap first port of call. The immobilizer system has a few components and it's quite simple in operation. The components are as follows

Immobilizer control unit (integral part of the dash cluster)
Reader coil (part of the ignition barrel)
Wiring
Key

A simple wiring diagram of the circuit -



If you are presented with a non start and an immobilizer light flashing (poss fault code of key signal to low) try first moving the steering column up and down and back and forwards, you would be surprised how many times this works, it's also a pretty good bet that there is a connection issue at this point. If this doesn't work and you are able to try the spare key. If it starts on the spare key for have a transponder issue with that key. If the car still won't start I'd advise based on my experience carry out the following repair. If this repair is unsuccessful it's probably a new barrel reader coil, but for the cost it's worth doing the wiring first I'd say.

As you can see from the wiring diagram it's a very simple circuit, the control unit is looped around the reader coil. When the transponder is placed next to the reader a signal is picked up and the immobilizer is deactivated and the engine will start.

The actual issue is normally the connector that goes onto the reader coil, a poor connection here means the signal drops out and the car won't start. I have had issues with the wiring too, that's why I'd advise making what we call an overlay. This means you disconnect the existing wiring and run the new one over the top and connect at both ends.

Making a loom

You need

Plug -



X2 repair wires



Take a connector end of each repair wire and slot into the connector piece.



Then slide the top of the connector in from the side.



Make a note that wire in slot 1 goes to terminal 1 on the dash plug, number 2 goes to 17. Twist the wires together as per standard loom (this helps with signal noise from adjacent wiring) and tape at the end.



There you have a repair loom. At this stage I'm not going into the fitting of it, I may do at a later date but basically it plugs into terminals 1 and 17 of the green connector on the back of the dash cluster.

Hope this helps, feel free to question/comment. If anyone needs this doing of course I'd be more than glad to carry out the repair for them.

I have made two of these looms now for sale, pm me for details.

cheers for the info--how does the coil come off the lock barrel once it's out       don't want to force it but it's not clear what's holding it on??

The coil doesn't come off the lock barrel.

only with a hacksaw!!!!!!     just for info------to who ever is interested, the coils are available on fleabay @£23  there are two different styles of socket I think "key" and square     I'm assuming once off, you can gut the lock barrel and tumblers if necessary

Did a fitting guide ever get made for this too?

I haven't done one, I just supplied the two looms I had made up.

I still have mine that you sold to me, i just havent fitted it as i havent had a problem with it again. Really need to get round to it!

Hi,

 

I have a question regarding this little operation.

 

Does it require the full dash panel to be removed? http://workshop-manuals.com/skoda/fabia-mk1/body/body_work/trim_noise_insulation/dash_panel/removing_and_installing_the_dash_panel/

 

Or is removal of the bottom dash panel sufficient? http://workshop-manuals.com/skoda/fabia-mk1/body/body_work/trim_noise_insulation/dash_panel/removing_and_installing_bottom_dash_panel/

 

Thanks!

 

 

Neither, just the instrument cluster (clocks), steering wheel and column shrouds.

Hi

are you still selling these cables?

How can I get some please?

Sold the cables ages ago. Pretty easy to make though.

I cant find the parts any ideas where I can get them as you say looks easy enough ?

Two of these will suffice: http://www.ebay.com/itm/Audi-VW-Skoda-Seat-repair-wire-000979018EA-selective-gold-plated-/171686376760?hash=item27f94e3538

You don't need to buy a new plastic plug, as you can easily reuse the one already fitted on the old cable.

 

Not sure if this applies to your car/model, but I advice against buying new cables before reading http://www.briskoda.net/forums/topic/369663-yet-another-fabia-immobilizer-thread-solution-included/?p=4363256

Maybe I'm just being a bit outrageous here, but Tech1e showed the VAG part numbers - and all VAG dealer's parts department can order that in for you, I bought the repair leads in years ago for a "just didn't happen" mod to my old Passat!

Two of these will suffice: http://www.ebay.com/itm/Audi-VW-Skoda-Seat-repair-wire-000979018EA-selective-gold-plated-/171686376760?hash=item27f94e3538

You don't need to buy a new plastic plug, as you can easily reuse the one already fitted on the old cable.

 

Not sure if this applies to your car/model, but I advice against buying new cables before reading http://www.briskoda.net/forums/topic/369663-yet-another-fabia-immobilizer-thread-solution-included/?p=4363256

Useful post thanks.

Hi Tech1e

 

Excellent post on the perennial Fabia immobilizer problem

 

I have removed enough dash furniture to access the instrument cluster, wiring loom and ignition barrel. I can see that the original reader wires, green and black I believe, have been cut and folded back in the loom.

2 yellow wires have been installed between the the reader and instrument cluster. Interestingly they have not been twisted, so could possibly be affected by interference.

 

While I have access to the immobilizer gubbins, I would like to check the electrical integrity of the immobilizer circuit. Can I use a multimeter to measure from the T32 connector towards the reader. What resistance would I be expected to read?

 

Thanks in advance

 

NPC

Update so far

Used a multi-meter and measured from the solder pins, at the back of the green connector on the instrument cluster.

I just wanted to prove electrical connectivity across as many variables as possible i.e. across plugs and connectors.

Read 23ohms total resistance for the yellow wires and reader coil. This seems to be about right, judging by other posts.

Twisted the yellow wires and held with black tape, as Tech1e suggested.

I then plugged in only the instrument cluster connectors and re-connected battery. So with all dash furniture and steering wheel still removed, inserted the ignition key, and hey presto no immobilizer light and engine started.

I will now start putting dash furniture, steering wheel and other connectors back together. At each stage I will keep checking immobilizer functionality, including turning steering wheel and adjusting up and down.

Hope this helps someone else.

NPC
 

Have you re-flowed the solder of the relevant two pin connections on the back of the green connector? Or at least inspected them as closely as possible and concluded that there are no cracks in the solder?  Would highly recommend doing one or both of these things before re-assembling everything.

On 12/07/2013 at 16:17, Tech1e said:

As I have had a fair few PMs on this issue and seen a little traffic on the forum I though I'd make up a little guide on what is a fairly old concern.

The symptoms would be a non start, possibly intermittent and the immobilizer light flashing on the dash. This can be for many reasons but this is quite a good cheap first port of call. The immobilizer system has a few components and it's quite simple in operation. The components are as follows

Immobilizer control unit (integral part of the dash cluster)
Reader coil (part of the ignition barrel)
Wiring
Key

A simple wiring diagram of the circuit -



If you are presented with a non start and an immobilizer light flashing (poss fault code of key signal to low) try first moving the steering column up and down and back and forwards, you would be surprised how many times this works, it's also a pretty good bet that there is a connection issue at this point. If this doesn't work and you are able to try the spare key. If it starts on the spare key for have a transponder issue with that key. If the car still won't start I'd advise based on my experience carry out the following repair. If this repair is unsuccessful it's probably a new barrel reader coil, but for the cost it's worth doing the wiring first I'd say.

As you can see from the wiring diagram it's a very simple circuit, the control unit is looped around the reader coil. When the transponder is placed next to the reader a signal is picked up and the immobilizer is deactivated and the engine will start.

The actual issue is normally the connector that goes onto the reader coil, a poor connection here means the signal drops out and the car won't start. I have had issues with the wiring too, that's why I'd advise making what we call an overlay. This means you disconnect the existing wiring and run the new one over the top and connect at both ends.

Making a loom

You need

Plug -



X2 repair wires



Take a connector end of each repair wire and slot into the connector piece.



Then slide the top of the connector in from the side.



Make a note that wire in slot 1 goes to terminal 1 on the dash plug, number 2 goes to 17. Twist the wires together as per standard loom (this helps with signal noise from adjacent wiring) and tape at the end.



There you have a repair loom. At this stage I'm not going into the fitting of it, I may do at a later date but basically it plugs into terminals 1 and 17 of the green connector on the back of the dash cluster.

Hope this helps, feel free to question/comment. If anyone needs this doing of course I'd be more than glad to carry out the repair for them.

Hi any chance you can put up the pictures as i can't see them for some reason and need a little help 

Photobucket has changed their hosting policy and now you have to pay to link onto a web page. 

I've got the same intermittent immobiliser issue. Mk2 VRS Octavia TDI. Auto electrician guy thinks it's my instrument cluster?