My V50 engine suddenly turn off and fault notice immobilizer pops out. What could be the problem? The mechanic says it could be due to the faulty key fob. Is it true?

 

Yes, it could be a bad key fob. Hopefully you have another key - if it works, the one that doesn't is defective. If neither works, then it's something with the immobilizer (and there are quite a few things that could cause it to fail).

 

Too bad for me because that is the only key fob I have when I bought the car from the previous owner. I hv scanned the key fob at the auto key shop and it is nothing wrong with it as it is “readable” . So now it could be with other things as what u mentioned. Could such ignition or plug coils be a culprit too?

 

did the car start back up? If you got a message on the dash, try scanning with an OBD2 code reader to see if there's any stored fault codes. I wouldn't suspect ignition as I'd suspect a fault there would throw check engine codes. I would also check system voltage since low voltage can throw off the computers and devices.

 

yes the car did start back but after I hv disconnected one of the battery terminal and waited for 15 mins before reconnecting it back again ( as advised by the mechanic as I hv stranded by the roadside). Once back to the workshop, the mechanic couldn’t find any other fault codewhen scan with OBD and he has suggesting about changing the plug coils.

 

No offense to your mechanic, but I think it's time to shop for another one. Bad coils is about the LAST thing I'd suspect in your case. For the car to not start, and then to start fine (after battery disconnect), the only way coils could be the problem is if three or four of them were failing on and off at the same time. Yeah, theoretically possible, but so is winning the lottery five times in a row with one ticket each. ;-)

If the car is starting now, and isn't throwing a code, there's really not much you can do other than to throw parts at it and hope for the best. I wouldn't ever recommend that approach, and certainly wouldn't suggest it with your mechanic's suggestions... troubleshooting doesn't seem to be his strong suit.

 

Thanks and yes , agreed with you . So far have’nt let him changed those coils yet. Will look for other shop.