Advice please, Possible key or immobiliser problem?

[Beardo]

Can anyone give me any advice on the following problem?

I have a 2005 plate A3 2ltr TDI Sport

Last week she was running fine! I stopped at the garage on my way home and when I came out and tried to start the car all the electrics worked fine but it wouldn't start. It didn't even attempt to turn over the starter motor and there wasn't even the audible click you usually hear when the battery is fried.

I called the AA and continued to try to start her while i was waiting but no joy. I then engaged the steering lock and used the key to take it off and the car started. (although this did the trick I'm reasonably sure it was just a fluke)

I used the car over the weekend with no issues and then yeaterday I got in it to go to work and it wouldn't start again. I haven't been able to start it since and i'm stumped.

Someone suggested that i should try my spare key in it, something to do with an immobiliser chip in the key? Has anyone had the same issue? cause? solution? Or any general ideas welcome.

Thanks in advance for any help.

 

[mike foster]

Did you try the spare key ?

Sounds as though the immobiliser in the instrument cluster is not recognising the chip in the key fob. This chip is pre programmed and not powered by the key fob battery.

You need to get the car scanned with VCDS or similar. I presume the key will turn the ignition on ?

May be worth disconnecting the car battery for a short while (say 30 minutes) to see if that resets the electronics. Sometimes they can get confused and lock-up for some reason or other. You will then need to reset a few things back to what they were set at i.e. computer readouts etc.

Worth a try and doesn't cost anything !

Good luck and please keep us informed as to the outcome.

Cheers

 

[Beardo]

Hi Mike,

I haven't tried the spare key yet as I'm at my office. I'm leaving now so i'll try all the suggested metyhods tonight and report back tomorrow.
I spoke to my VW dealer (Independant and reasonably priced) and he says he can get it in towards the end of this week if i have no joy but advised me that there's a possibility it may have to go to the stealers if the problem is too in depth.
Fingers crossed.

 

[Khufu]

Well the immob cuts out after a second or so of it starting so im not sure its that. It could be the switch that the key turns that's attached to the barrel. Had those going on other cars.

 

[Dave's A3 sport.]

Had a similar issue on my old car, turned out to be the terminal 15 voltage supply relay which plugs into the onboard power supply control unit underneath the drivers side of the dash. Worth a try, hope this helps!!

 

[Beardo]

Hi Guys,

Just an update, I tried the spare key last night and no joy!
Tried disconnecting the battery and same result. I am reasonably sure it's the micro switch on the barrel based on conversations with others. Got a buddy of mine popping round over the next couple of days to look at it and will keep you updated. I seem to remember having a similar problem on my old MK4 Golf TDI and apparently it's the same set up so fingers crossed.

 

[NHN]

It could be the relay needs scraping with a screwdriver as they do get some build up on them which makes contact sometimes crappy, also the barrel is another, even the steering cu could be at fault which is what happened to mine.

 

[Beardo]

Hi Guys,

Sorted!
Sure some of you are aching to hear what it was and in the hope it can save anyone else the trouble in future here goes.

So i got a mecahnic out to look at it and he couldn't find the issue straight away and as he was convinced it was some sort of electrical problem he reffered me to a vehicle electrical technician he knows.

Charge for the mechanic to come out £0.00

The technician was out within 2 hours, he did his checks and found that there was power to the fuse box but no power from the fuse box to the starter motor. He bridged to the starter and the car fired up.

On investigation he found that the power lead to the starter motor is encased in tubing to stop chafing against moving parts (a good idea in theory) but when he went to test that cable it fell apart in his hands. Basically water gets into the tubing over time but doesn't drain out. It rotted the cable completely. He replaced the cable and the car started perfectly.

The main issue then was that the car started showing loads of faults which he was able to investigate and clear down except one.

The ESP and steering lights were both on and showing a fault. the fault description said the steering sensor needed recalibrating but the method shown on how to calibrate it excluded vehicles with ESP.
It wouldn't allow a clearance of the code and on inspection the fault code had knocked out the power steering.

He had done all he could and said i needed to get the stealers to recalibrate the steering and reset the computer.

Cost for 1 and a half hours technician time £60.00

Called the stealers yesterday and told them the problem and they told me they would look at it today but there was no reason the power steering should not work because of a calibration fault.
They quoted £103.00 for the recalibration and promised an advisory call if anything else needed doing.

Blow me over with a feather if they haven't just called me and told me i was right, they recalibrated the steering and reset the faults and now everything is working fine.

Cost all together £160.00
Car off the road 2 weeks.

Hope this helps anyone else with a similar issue in the future.
Check your starter motor cables too guys, maybe worth a dab of silicone to stop water ingress.

Cheers for the help and comments.

 

[Khufu]

Thanks for the follow up. Glad you got it sorted. We've been caught out before & ordered up a starter motor only to find it was a lead falling apart.

 

[mike foster]

Thanks Beardo - thats a new one on me !!