Engine Immobiliser Fault

[reconoistre]

I have a pug 406 estate with immobilizer fault, turns but will not start of course though the engine turns ok. When I turn ignition on windscreen wipers start, also headlights turn on though switches show them turned off BSI is nice and dry and clean,but driver's side carpet really quite wet any constructive ideas or experience welcomed.

[lozz]

Hello..

There is some wiring/connectors in the drivers foot well..under the carpet
Iirc this is the prime area for 'electrical poltergeists on 406s..

Hopefully someone else will have a better idea..

[reconoistre]

Thanks for the swift response, I will have that carpet up tomorrow. Do any of those under carpet connections link to the key barrel aerial ? Last time it immobilised I tweaked the aerial and was able to drive it 60 miles without incident, but next day the damned car deadlocked me inside for twenty minutes (before a neighbour rescued me) then went into Economy Mode!

[Doggy]

Hi & welcome aboard.

lozz is right - first stop is check for a soggy drivers footwell carpet and waterlogged connectors below.

This should help. viewtopic.php?f=10&t=13347

[Doggy]

Do any of those under carpet connections link to the key barrel aerial ? Last time it immobilised I tweaked the aerial and was able to drive it 60 miles without incident, but next day the damned car deadlocked me inside for twenty minutes (before a neighbour rescued me) then went into Economy Mode!

Hard to say, the effects of dampness seem pretty random, best to rule it out at least.

Economy mode kicks in after 30 minutes on accessories / ignition position with engine stopped. Clears when you start it, (assuming it'll start).

[lozz]

Best bet is ..disconnect the 'battery..
Just to be on the safe side.. the bsi is rather sensitive ..so to save it fizzling out
Take a lead off..

Iirc there was a guide of some sort on the forum of the wiring in the foot well..
Icarnt rember who made it.. a taxi driver perhaps..
Someone else might know..but its worth a look..

[lozz]

Edit.. doggys linked it..

Nice find..

[reconoistre]

Thanks this is really helpful and gives me some hope of curing the problem , I also have a VW Passat which also suffered from dampness under passenger side carpet and corroded vital wires to electric window

[lozz]

Good luck mate..

Let us know how you get on..

[reconoistre]

I will post an update tomorrow

[reconoistre]

A little progress made finally got some time to look at the problem but now need to find out how to raise the drivers footwell carpet. Did manage to prise it up a little and found about 1/2 inch of water in the footwell not to mention the sodden foam rubber stuff, so I really think I am onto something signifigant. Really grateful for the helpful pointers here.

[Doggy]

Sounds promising.
Try looking at that area of the floor from underneath, see if there's a rubber grommet you can push back inside with your fingers, or something blunt and let the water out.

[markw]

Thankfully never had this problem on mine (yet) but you are going to need all the access you can get down there to effect repairs properly. Trying to struggle underneath a partly folded back carpet will make the job very frustrating indeed......
I'd suggest planning a full weekend for this job and take out the seat, all the necessary trim, lift the carpet up a high as possible to get air under it, drain out the water then dry off the remains of your connectors(!) and assess the job from there.
If terminals are corroded/missing/damaged, soldering straight through joints will be the best solution.


Then you have to find the leak........

Good luck with it.

[reconoistre]

2014-10-01 10.41.20.jpg

Yes now I am the leak stage, found the large multiplug badly corroded with three trangs completely eroded off. Cleaned up with vinegar, and bicarb then WD40 rejoined three wires outside the plug and it cleared the immobiliser fault and started first turn of the key.

[lozz]

Well done..

You' wouid now be best to invest in some wax 'oyl'.
And give the floor well agood few coats..