[plbuckland]

One of my 166 has let me down badly. Went to start it at the supermarket and it wouldnt start. The code light was on so obviously the immobiliser wasnt talking to the key I guess. Repeated attempts to start it failed even after disconnecting and reconnecting the battery and checking all the fuses. So I picked it up and brought it home. After sitting there for a couple of days I tried to start it again. This time the code light went out but it still wouldnt start. So did a full ECU reset and Voila, it goes again. But why did it happen in the first place??
And just a question about the airbag light(s). The red one has been on for a while si I know I have a problem there, but now there is a flashing orange light to the right of it which also looks airbag related, but wasnt on before.

 

[a17esh]

Maybe check earth connections. Starter motor and crank sensor?

 

[ChrisS]

That sounds very much like the problem I had with the airbag on mine. The airbag ECU complained that there was a problem with the passenger airbag disable light, even though there wasn't, so lit the red one, then it complained that the red one was faulty, which it wasn't and flashed the yellow one as a backup fault indicator.

First step is to interrogate the airbag ECU and see what errors are stored. My guess as to the likely cause is a leaking heat matrix has led to corrosion on the airbag ECU connectors.

Once or twice mine has also failed to start with a CODE light on the dash. Happens when I am a bit too quick turning the key. If I turn it off, then on again but pause until the CODE light goes out then crank, it fires up no problem.

 

[plbuckland]

My other 166 has always been like that. You have to wait momentarily till the code light goes out before starting. But this was different, the code light stubbornely refused to go out. Next day after trailering it home the code light did go out but it still wouldnt start.Upon interrogating it with AlfaOBD it came up with some strange messages, first one was Engine start: Disabled and the next one was that the fuel system was disabled. That was when I decided to do a full ECU reboot and after that it went normally. I am really curious as to why it failed to read the code and wondering when it will happen next......
As for the airbag light i was not surprised at that as before I bought it it hasd had some sort of accident and I have assumed the airbag maybe had gone off although I couldnt see any indication any of them had. But I was curious as to why the other airbag light came on at the same time the code fault showed up, no matter what position the on/off switch is in.

 

[ChrisS]

That CODE problem does sound a bit worrying. I think they can be a bit voltage sensitive, but given you had only just parked up, that seems unlikely.

The airbag system is pretty persistent in trying to alert you of a fault, real or imagined....if the airbag ECU gets unplugged, the dash lights the red warning lamp itself, if the airbag ECU fails to detect the red light, it flashes the amber one, if it fails to detect the amber one, it lights the red one....

 

[plbuckland]

Well it has happened again The code light came on again and it wont start. Disconnected the battery again for an hour but the code light was still on. It goes off intermittently but still wont start. Eventually managed to log in and it said there were no faults but theen later it came up and said there were faults but couldnt read them. But it is also very hard to log into and will only log in using the bluetooth ELM 327 dongle. Very very frustrating. I took the codebox out and all the terminals seem OK. Using the other key does the same. Mystified

 

[plbuckland]

Thought it may help someone in the future if I explain what my problem was. The report from the AlfaOBD software was reporting a low voltage situation, which led me to suspect a poor earth somewhere. Sure enough, I found the earth on the back of the cam cover on the front bank was loose. Tightened it up and the problem was fixed.

 

[ChrisS]

Good result and thanks for the update. I'm guessing this is a CF3 car with the ECU bolted to the plenum?

 

[plbuckland]

Yes, but the earth that caused the problem was the heavy earth wire that bolts onto the rear of the front cam cover.

 

[ChrisS]

Interesting. Did it crank over OK? Just wondering if there could be an issue with the main engine earth cable as well. On the one I scrapped recently that one looked OK but on close inspection the end that bolts to the gearbox foot was rotted underneath the plastic sheathing. Might be worth a quick check.

 

[plbuckland]

No it cranked over OK. It hadnt been tightened after a belt change a few weeks previously. No other issues. That car has only done 70000km

 

[ChrisS]

Cool. I'll stop fretting then :biglaugh: