My wife's had her 2011 159 1750TBi (demo model) for about 3 months now, and there's been a recurring problem. Pity - otherwise the car's great.
The check engine light came on in the 2nd week, and the dealer advised that there shouldn't be much of a problem - we should bring it in in a weeks time, even though we asked for an earlier visit just to identify the issue on the diagnostic system! (NOT my idea of dealer support, and I wonder whether Alfa should put up with such a cavalier attitude). As this was a Friday, and the car refused to start on the Monday SWMBO was not pleased ...
We were told the problem was a dead battery and an oxygen sensor connector. Battery was replaced and we were NOT told that there might still be a problem with the sensor or wiring.
The light's now come on again, and this time we got the car in the next day (this morning).
It's apparently the sensor connection - the wiring loom, to be more specific.
The trouble code is P0134 'preheat resistance 1 upstream fault'. The connection is apparently bad again. This is the upstream oxygen sensor - which is, of course, absolutely fundamental to managing fuel mixture in any injected car. AFAIK, in most (all?) cars, if this sensor isn't working, the mixture is determined using default mapping & you can expect degraded performance, fuel economy etc. If it's only a preheat problem, though, it might be working after warm-up if the ECU allows it (but I wonder: if the connection is pulled away enough to open circuit the preheat, would there still be a signal getting through?).
The proposed solution is to replace the wiring loom to the sensor according to 'service news 55.02.11' as the factory loom is too short and a new longer one is now available. We're booked in for this when the loom arrives. This must mean that the factory loom is so short that the connector is pulling off the sensor.
A few questions / points:
1. Am I right in being highly annoyed
a. There was initially absolutely no sense of urgency in checking out a recently sold car with the check engine light on?
b. The connection to the oxygen sensor must have been seen as obviously too short but no attempt was made to rectify this (any half competent auto electrician could splice more wire into a loom ...) nor was the customer told.
c. Alfa seems to have a bodgy battery supplier - hardly a smart way to save money - I've read elsewhere that early battery failure is quite common.
2. Has anyone else experienced this issue - and was the loom actually the problem? (My confidence in this diagnosis isn't high ...).
3. Does anyone know the release date for service news 55.02.11 (the '11' makes me think it's been around for a while)?
4. If anyone else has had a faulty 1750TBi Oxygen sensor connection looked at and just pushed back on, they might want to go to an Alfa dealer and ask about this new loom before their warranty expires ...