Technical Replace ECU or not?

[grahamgaj]

I have recently bought a Brava 1.6 SX - R reg - no lights showing on test drive.

Fuel injection warning light comes on from cold start - stays on for about 3-5 mins when car is slightly rough but then goes off and will stay off for the rest of the day - even on restarting - after warming up car seems fine and to be honest fuel consumption is about 30'ish to the gallon so haven't noticed any major fuel issues. The temp guage never goes to mid-way but sits about a 1/3 up the dial.

After checking all the questions on the forum I took the car to dealer for fault testing with me assuming that maybe thermo sensor dodgy or thermo sticking open. Fiat are telling me that the fault reading is:

"self-adaptive parameters intermittent"

and that I need a new ECU at about £500.

They were not willing to tell me what this actually means or why my light goes off after two minutes and if I continue to drive the car what does this fault mean to potential damage.

Any help in understanding this would be great - do I really need a new ECU, shall I ignore it or shall I send to someone like the ECU Dr?

Thanks

 

[jug]

this fault means that the ecu cannot store operating parameters on its memeory, ie it cannot learn, and although it could mean the ecu is faulty it is more likely that the ecu has a dodgy wire on one of its permanent lives, you need to consult a haynes manual to find which pin(s) provide a permanent live to the ecu, then remove the wiring harness for the ecu and test the curcuit for each live pin using a multimeter. attach positive terminal of tester to the battery positive lead (with the battery disconnected) then touch negative terminal of tester to an identifed live pin. measure resistance across this circuit, it should be low, if you get a open curcuit on the multimeter you have identifed a broken wire, a high resistance suggests a corroded wire connection. if the wiring checks out then it is safer to assume the ecu has damage to its memory. what i would be more concerned about is why this happened in the first place. the memory on ecu's is virually bulletproof. it can be easily wiped by magnetic fields but this would not prevent the ecu from relearning, the only likely cause is a large electrical surge, water damage, or a nasty direct impact. i would not go to fiat for a new ecu either way, there are plenty of ecu repair places on the web who are cheaper. and another thing, don't take fault code readings as gospel, they have been wrong for me on more than one occasion, and fiat have misinterpreted them before too. its a hard life

 

[jug]

what is interesting is that the ecu relearns everytime the car is started, suggesting its memory is physically ok and working, and it only forgets the stored parameters after some time, which is the same as resetting the ecu, it takes time, sometimes as long as a couple of hours, so i now think that your ecu is definately ok and the problem is that the ecu is not getting a permanent live from the battery, basically you have an auto-reset effect on your ecu because the memory depends on the ecu having power at all times. i'm convinced thats the problem. i'd be willing to bet money that a dodgy wire is all you need to fix

 

[grahamgaj]

many thanks for this - I will check this out.

I owe you a few pints - cheers!