Immobiliser problem - or what?

[hemming]

My 16K mile, 63 reg CVT is with the supplying (and sole servicing) dealer where they may not be able to look at it for 10 days!!
It has refused to start on 3 occasions in the last month. On the first 2 the AA managed to start the car after about 30 minutes by many random combinations of locking and unlocking the car with both of the keys in and out of the car. Their diagnostics showed no fault and the battery terminals were checked. The third attempt failed entirely and the car was transported to the dealer.
The prevailing view is that the immobiliser is the problem but I am wondering in the first place whether anyone has had this problem and what the solution and cost was and secondly whether the symptoms were in fact down to something altogether different and again its solution and cost.
Any help would be gratefully received.

[guest1372]

Once hooked up to Honda HDS, the conversation with the immobiliser will be logged so all should become apparent; of course it will probably decide to behave faultlessly while they have it.
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TG

[Steve_M]

What is the symptoms when it won't start? Won't turn over? Or turns over but won't start? Does the immobiliser light flash?

[nab]

I know this may sound silly? but the engine will not turn over at all in the CVT if the auto shift is not in the P position .This is for safety reasons . 

[Jocko]

I know this may sound silly? but the engine will not turn over at all in the CVT if the auto shift is not in the P position .This is for safety reasons .

So a faulty/maladjusted Park sensor could prevent it turning over?

[hemming]

Thanks all for the thoughtful replies. Sorry, I should have been more specific, the engine does turn over as normal but won't start and the green immobiliser light comes on and immediately off when the ignition is turned on. When I speak to the dealer again tomorrow I will mention the points made and will post again to let you know how and when the problem is eventually resolved.
In the meantime it's Shanks and the bus!

[hemming]

As promised, an update- of sorts..
Collected the car today, diagnostics showed no fault; during the time the car was with the dealer it started first time every time and they reprogrammed the 2 keys merely as a precaution. They could offer no explanation whatever except that it did not appear to be related to the immobiliser.
I thought this through afterwards and realised that it was perhaps more than a coincidence that every time it refused to start it was sat on the drive adjacent to the front door and the garage door. I am now wondering whether there may be some "interference" between the electronic garage door remote and/or the electronic door bell - sounds like grasping at straws but I've isolated both and will see if the problem reoccurs. I'll post again as and when.
Thanks again for the replies.

[culzean]

I thought this through afterwards and realised that it was perhaps more than a coincidence that every time it refused to start it was sat on the drive adjacent to the front door and the garage door. I am now wondering whether there may be some "interference" between the electronic garage door remote and/or the electronic door bell - sounds like grasping at straws but I've isolated both and will see if the problem reoccurs. I'll post again as and when.
Thanks again for the replies.

Is your doorbell wired or wireless ?  Your garage remote is certainly going to be radio frequency.

A few years ago after I had installed a wireless doorbell it used to go off and when I opened door sometimes there was nobody there     After a short while I noticed that whenever the guy next door got out of his car our doorbell would ring,  the frequency of his (Vauxhall) remote was close enough to our doorbell to make it ring.  Luckily I was able to change the frequency of our doorbell and it cured the problem.

I don't know if our doorbell ever interfered with his immobiliser and caused him problems, I guess after I changed frequency it would be OK anyway.

[hemming]

Thanks that's interesting - and yes, the doorbell is wireless.
Since I posted I've realised that the car keys have been right next to the hands- free phone and also the computer router, so the keys have been moved away too. It all seems a bit suspicious but on the other hand I would have expected that, if it was any of these items causing interference, I would not have been the only one to have had problems!

[John Ratsey]

I wouldn't expect another device on a similar frequency could upset the immobiliser unless it was transmitting at the same time as you were trying to start the car. Door bells etc only transmit when the button is pressed.

[guest5770]

I have read of similar problems to this. There is a suspicion that some cheap wireless devices which don't comply with EU shielding regulations can interfere with the frequency that car remotes use.

[culzean]

I wouldn't expect another device on a similar frequency could upset the immobiliser unless it was transmitting at the same time as you were trying to start the car. Door bells etc only transmit when the button is pressed.

The low power device 433MHz band is very congested,  everything from wireless domestic central heating thermostats, garage doors,  doorbells etc. etc. uses it - the device may not have to be transmitting at same time,  if the immobiliser receives an uncoded signal at any time it may upset it enough to make it not work next time you want to use it.

There is a newer band allocated at 868MHz to ease congestion,  but with the explosion of wireless devices it wont be long before that gets crowded too.

[hemming]

By way of an update, a couple of days after my last post the car would not start again, nor on the day after. By this time I had lost all faith in the dealership and on the recommendation of 3 neighbours contacted a local independent garage with a good reputation. They arrive less than 2 hours later, spent over half an hour on the drive, could not start it and recovered it to their garage about 3 miles away. They phoned me the next day to say they had identified the fault (an intermittently faulty fuel pump relay) and although a replacement was not in stock at the dealers, it was on order and should be with them today.
I duly received a call just after midday, was collected 10 minutes later, driven to the garage and picked up the car. The total cost was £160 (made up of labour on Friday and recovery £50, labour charge £60, parts £25, plus VAT).
The attitude and service from the independent far exceeded that of the dealers. No prizes where I shall be going in future!!
Thanks again for the help and advice given on this site. 

[Jocko]

Why not give them a name check?

[guest1372]

Excellent news and a fair price.

If anyone needs to check a relay, the under bonnet ones are all the same so you can swap them with the horn relay and check them by bibbing that.
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TG