[ubay]

I had the wieredest experience today, hopefully someone can help me.

I Drove to work, all fine car unlocked/locked perfectly fine.
2 hours later i go back and the car wont unlock with the remote, (me thinking the *remote* batterys gone) so i use the key to unlock the drivers door. I get in and push the button to unlock all doors.
No doors unlocked.  Thinking i gotto go, i drove off (No warnings on dashboard).

Start driving and then the boot open displays, i pulled into the nearest car park and the boot wont open with the button. Got back in and used the manual release slammed it shut.
Boot Light still flashing. NOW ive just realised the rpm is stuck on 900 rpm (engine is off). I turn ignition on and then off. rpm resets. then i start the engine and turn it off (and it sticks again?) same procedure as before to reset it

Now after about 10-15 manual opening of the boot and slamming it shut (bearing in mind all doors are still locked and wont open and heres me climing over from the drivers seat) it has finally locked.

Is my car possessed or has anyone got any ideas?

[asathorny]

I think it't time to disconnect the battery for 20 mins so that the ECU is forced to reload.....

However following my advice is always risky cos I know nothing.

Someone whom actually knows what their on about should be along anytime soon.

Good luck   

[eye30]

It is possessed!

Do what Asa suggests as a first step before you take it to garage as this does seem to rid cars of little oddities like your experience.

Ps
Amy chance battery has discharged recently and it needs a full charge up?

[ubay]

I had the car battery out last week to tickle charge it too full, (as it was starting to get a little frosty in the morning) and I want to maximise the starting power.
The reference to the battery previously was the one in the key/remote.

I will disconnect the battery when i get home and see what foibles it decides to have tomorrow.

I guess it is possessed

[asathorny]

Yeah we have all sorts of problems with satanic possession  <sigh>   

[Asterix]

Could be a door switch not operating correct. Have you checked the interior lights react on every single door both when opening and closing..?

Does the turn signals flash when using the remote..?

[Dazzler]

I would suspect the guys are on the right track. Battery/ BCM  reset. I suspect the tailgate may need adjustment to engage the boot shut / boot light switch or the tailgate wasn't shut properly and zapped the battery a bit. Low (car) battery is then upsetting the electronics. However, I am only slightly less senile than Asa, so don't sue me if I'm wrong!

[ubay]

Tried unplugging the battery held the brake for a few secs then turned the ignition on to drain the residual power.

Today driving home, the internal lights started flickering, still have the same problem with the boot light and the doors not unlocking and now my OBDII tool wont talk to the ECU.  i cant turn the lights on now either.

Any more pointers or do you think its a garage job?

[asathorny]

Unless our Techies, and we do have top techies, have some other ideas I guess it's off to the dealership <sigh>

Good luck 

[ubay]

Just went back to try again, and it didnt unlock with the remote and wouldnt talk to the obd tool. A few ignition cycles later bam, interior lights come on (as the drivers doors open), all locks click into life and the Ecu is talking with with the tool.... But no error codes and all parameters seem correct (using a Sealey TA500).

and it locked with the remote, unlocked and locked again. this is getting seriously weird. My moneys on the BCM.

I have booked it into my nearest dealer later next week, they guy on the phone had no idea either. Hoping its not an expensive fix otherwise its off to the scrappers/sell cheap/ or beg for a part ex on the Ioniq.

Will let you guys know what the problem actually is, in the meantime any other suggestion, par taking the dashboard off to get to the BCM is appreciated.

[Dazzler]

I'd be giving your battery another trickle charge.

[edagrade]

Seems the vehicle needs a thorough check over.
This should include full battery & charging system test (replace battery as required, despite trickle charging), powers & grounds at battery, body & main control units (ECM, BCM, etc) followed up with some fault code diagnostics.

Generally speaking, power & ground issues are far greater causes of such symptoms of 'possession' than a control unit being at fault.

[ubay]

The local Hyundai service centre has had a look today, and as expected the car decided to behave impeccably for them.

Their techies haven't been able to find a single fault with the car, I have agreed for them to keep it for another day or so in the hopes that the gremlins decide to show themselves.

Maybe the BCM reset worked? Only time will tell.

[ubay]

The Hyundai Service centre still have no idea but, "suspect" (actually written in the report) an internal failure of the BCM and advised replacement at a cost of ....... £1,300, Which is ridiculous.

I think it may be time to say goodbye. 

[beerman]

For that kinda money you would want more than a hunch. 

Doing some googling do discover what a BCM is, it looks like a fairly simple fix, they appear cheap online, and from my very brief reading, there isn't much to changing them over. The only problem is once done the keys will need to be reprogramed.

So it might pay to get an auto eletrician who can reprogram the keys to do the job, less mucking around.

[edagrade]

So, why not get an auto electrician or other suitably skilled technician to actually diagnose what is causing the 'possession' before the owner is dispossessed of $ to replace a BCM?
Had anyone considered it maybe an instrument cluster fault, or comms faults between cluster & BCM caused by poor connections, earths or power supplies?

Obviously the Dealership is just not interested in a diagnosis - they would rather hit the owner for a big bucks 'stab in the dark' "repair" with no responsibility taken for it solving the 'possession' - or sell the owner a new car... win win situ for the Dealer either way isnt it? 

[nzenigma]

Interesting. Apart from your unscrupulous dealer ,everyone's suggestions from the very senile down (or up) to Beerman have been worthwhile. Especially looking at the BCM.
I agree that a good auto electrician will be the most useful guy to see. Unless you can find the cause yourself.
As an aside; unless you are only doing really short trips, the alternator, which is working at ABOUT 13-14V, will keep a good battery well charged. "frosty" mornings should have no affect unless the battery is near its use-by date.
If you open the drivers door with your key or remote, all doors and boot should be unlocked.
The flickering internal light and 'boot open' indication may  be due to a faulty connection in the tailgate or its lock. Worth the look.
The BCM also receives speed data. This may account for your 900 rpm. What is the cause.. hmmm.. the horse or the cart?