I'm pleased you light has gone out.
Regarding EOBD, fault code checking, etc. then let me hopefully explain in terms that you may be able to understand.
1) EOBD is simply Engine OnBoard Diagnostics. Originally required/enforced, I believe in Califorina USA, the EOBD system is an open protocol to allow state official authorities to check cars for faults that would increase vehicle emissions.
2) Since US requirements EOBD is now standard across USA and Europe plus other places. EOBD flags faults and is very specific e.g. engine injector 2 malfunctioning.
3) Fault codes are either generic for all makes an models as required by EOBD standards or will be more specific/proprietory for systems and faults OUTSIDE of the required stardard requirements.
4) Given the above all modern ECUs monitor their performance and external sensor signals. If a fualt is found then it is logged, and depending on severity, may cuase the Engine Fault Light to come on.
5) Once a fualt has been logged the ECU will in most cases will either wait for the fault to be externally reset by diagnostic equipment AND/OR will continue to monitor for the fault and if the fault does not happen again within some many hours/miles the fault is removed from the system. On removal all warnings are reset.
6) Your Croma is equiped with and EOBD / diagnostic socket. This is located behind the little dasboard pocket to the lower RHS of the steering wheel (As are all the fuses). It is a 16 pin socket looking like this:
http://www.auterraweb.com/obdiipinout.html
7) EOBD diagnostic equipment ranges from simple fault code readers costing less than £50 to more advance ones which allow the viewing of sensors data streams. These cost around £100. Take a look at
http://www.gendan.co.uk/ There are plenty of other providers out there so I suggest you Google for yourself.
8) EOBD is Engine! Having said that the EOBD connector has connections for other car systems like Engine,Airbags,ABS,Power Steering, etc. etc. On some cars these system can get near 100 different types
9) Given what I have said in (8) then it becomes clear that for other than OBD/EOBD then more specialist software and hardware, like what the manufacurers/dealers use is required.
10) FiatECUScan is one of those more specialist tools that will allow, via a computer and suitable hardware (e.g. VAG/KKL or ELM interfaces), connections to not only Engine diagnostics but also many other vehicle systems depending on current model support (which is expanding every day....
http://fiatecuscan.net/
11) All the above is not rocket science and I hope if you do a little research/googling then you will get a better understanding.
12) Fiat / other garages have different charge rates for services. As you might expect an hours labour cost for a tyre technician will/should be less then that of an engine technician. Beyond that there are specialist diagnostic technicians. Yep, get to DT level and the cost to plug in a piece of computer kit, read a code, and report back what appears to be a "scientific" defacto diagnosis is expensive. Hopefully this expense is well justified as the technician has done a shed load of other tests, coupled with his/her extensive experience and knowledge to fully support what the computer says and and also rule out OTHER factors which could cause the same problem.
13) Regarding Fiat (or others) charging an hour to 'plug-in' and read an error can be both true and false. Reading the fault code is trivial. I could do this in about one minute and certainly less than five minutes. As eluded to in 12) there is/should be more involved that just reading a code. When it comes to certain safety issue faults, like ABS or Airbags then the tester/dealer is oblidged to run a full suite of tests to ensure that your car is 100% fit in every safety aspect. They would be fools not too. These tests, if done properly and professionally can take 30 to 60 minutes depending on system/fault.
14) With regards to 13) one can only hope that the garage/technician has done the job properly. Unless you watch over the guys/gals should for 100% of the time then you will never know if they did a 5 minute 'read code' or a full diagnostic.
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