One for the Car Techies

Mrs has an old 06 Hyundai Santa Fe she uses for work and we take the dogs over the field in

Anyway it has a strange intermittent problem where it just wont start, I think it's an immobiliser problem but I'm not sure

First happened 2 months ago, car was parked in a strange road, would not start, towed it down the road and it stared with a bump on the tow, I assumed it was another cars immobiliser interfering where it was parked ?

Anyway all well for about a month and did it again outside her work, towed it again and started, now again a month later it won't start outside the house, battery full and turning engine over properly, I know it will start with a tow but thought someone may have an idea ?

have you had the fault codes read . would be the first place to start as this could be hard one to trace down if no fault codes
have you tried the other keys

Thanks for reply tb

Just spoke to a mate of mine who said the same thing and is getting codes read for me later

Have tried both keys, I'm sure it is something to do with the immobiliser, just don't understand why it starts with a tow, strange

not sure if your motor has a duel mass flywheel but a friend of mine had the same problem as you with his ford c-max, he took it to the garage and they fitted a duel mass flywheel and clutch seemed strange fix to me for the problems he was having but it did fix it

If car is bump starting then I would doubt immobiliser problem, although immobiliser problems show up in different ways with different cars.
Coil packs can often cause non starting problems and would still be able to bump start, so perhaps another thing to consider.

knight said:

not sure if your motor has a duel mass flywheel but a friend of mine had the same problem as you with his ford c-max, he took it to the garage and they fitted a duel mass flywheel and clutch seemed strange fix to me for the problems he was having but it did fix it

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It does have a duel mass clutch but its not long had a new one in, the problem has happened before and after

D 8 RCS said:

If car is bump starting then I would doubt immobiliser problem, although immobiliser problems show up in different ways with different cars.
Coil packs can often cause non starting problems and would still be able to bump start, so perhaps another thing to consider.

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Forgot to say it's diesel, just went out and it has started this morning on the key, this is very strange, I'm still leaning towards immobiliser and maybe key & system glitching when recognising each other ? also someone suggested the crankshaft position sensor ?

suppose the only way to know for sure is have the fault codes read

Thanks for replies guys

crankshaft sensor fail are pretty common so possibly worth thinking about

I have a focus that did the same intermittent starting thing. It did seem like the immobiliser and in a way it was. The crank shaft sensor wasn't outputting enough signal to the ecu so the ecu woulnt allow the car to turn over. A new crank shaft sensor fixed it £15 of eBay and it was easy to fit.

Hope your problem turns out to be simple one.

im with @alimac its not the immo , its the first thing customers blame , u need to read codes and live data ie engine speed when cranking , intermittent faults a nightmare

just changed the crankshaft sensor on my old calibra as was taking 10 mins to start it lol
amazed it even ran when i seen the state of it on removal outer casing perished bare cables showing
cheap easy repair which i recommend doing if having issues

Check the earthing cable going to the engine they corrode very easily. If it starts with a bump it could be a faulty starter relay. Is it a diesel or petrol?.

The thread caught my eye as I have the smaller Tucson of similar vintage- touch wood it is OK. But I have had similar issues with a Citroen C3- the solution with that was to -Remove ignition key - lock doors with the remote - unlock doors again and it starts first time. In your case I am wondering if during the getting in & out etc. etc. to organise the tow might be inadvertently deactivating a temperamental immobiliser. It's an easy cost-free experiment.
If that doesn't work then the crankshaft (or other) sensor is a very plausible explanation and a fault-code readout should quickly point you in the right direction.

Hi! By my experience with Hyundai cars, especially if this starting problem is weather related ( dry and warm weather - car not starting, big humidity - car is starting) then your problem is under the steering wheel in the coil ring connector. - is the plastic ring around the key contact.
Pull out the connector (2 or 4 wires) look inside and if you see 2 black spots on the long pines ...TADAAA
Clean with a contact cleaner and bend a little bit the pins for a better contact.

Good luck.

kreepyme said:

Hi! By my experience with Hyundai cars, especially if this starting problem is weather related ( dry and warm weather - car not starting, big humidity - car is starting) then your problem is under the steering wheel in the coil ring connector. - is the plastic ring around the key contact.
Pull out the connector (2 or 4 wires) look inside and if you see 2 black spots on the long pines ...TADAAA
Clean with a contact cleaner and bend a little bit the pins for a better contact.

Good luck.

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Useful to keep in mind, thanks for that.
My Tucson has never had problems starting (touch wood!) but I do sometimes have problems persuading the cruise control to engage. It always works eventually- and once it has engaged once it's fine for the rest of the journey- so I have never investigated it any further. I have always assumed it's been something dodgy in the connection between the steering wheel-mounted switch and the column harness. Any idea how the connection is made?

It might be the crank sensor, seen it before on this age of santa-fe alltough usually they'll cut out randomly as well. Check if the yellow key symbol goes off when cranking, if it does then its nothing to do with the immobiliser. It could be a fuel pressure problem, sometimes the injectors can leak off too much fuel and stop the rail pressure building, needs at least 150 bar to start.
Not to hard to check just google injector leak off test.

Check your brake light switch if it goes faulty the cruise control will not come on because it thinks you are braking.

miggy said:

Check your brake light switch if it goes faulty the cruise control will not come on because it thinks you are braking.

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There was a recall for the stop lamp switches on Tucson, PM me you reg and i'll check if yours was affected and if its been done. There's a current recall to check and underseal the front subframes as well.

miggy said:

Check your brake light switch if it goes faulty the cruise control will not come on because it thinks you are braking.

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Funnily enough I did think it could be something like that, I used to dab the brake (and clutch) pedals to see if that would help, being as it was always intermittent it was hard to tell if it made any difference or not. It always engages- sooner or later.

thebigman said:

There was a recall for the stop lamp switches on Tucson, PM me you reg and i'll check if yours was affected and if its been done. There's a current recall to check and underseal the front subframes as well.

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It'll need to be the chassis no. mate as it's on Portuguese plates- hopefully the underseal thing won't be a problem here lol!

thebigman said:

There was a recall for the stop lamp switches on Tucson, PM me you reg and i'll check if yours was affected and if its been done. There's a current recall to check and underseal the front subframes as well.

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That is correct m8 it was a common fault. Get it booked in. Here you go fella.
Hyundai, Kia recall 1.7M vehicles for faulty brake switch

miggy said:

That is correct m8 it was a common fault. Get it booked in. Here you go fella.
Hyundai, Kia recall 1.7M vehicles for faulty brake switch

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I just read that article and I don't think it applies to mine. Interesting though how the makers say braking performance won't be affected. Hello? If the cruise control doesn't disengage when you brake (which is what can potentially happen with their issue) then I would have thought braking would be severely affected, especially in an automatic!

My problem is the opposite- it (cruise) is very reluctant to engage. I am still thinking it's more likely to be in the steering wheel or column (or interface) as, when it is being particularly obstinate, the green Cruise light goes off as well sometimes.
I've put up with it for the 8+ years I've had the car. It's no biggie, just thought it'd be handy if it was a known fault with an easy solution.