flash of death

[Cody Forbes]

On Fri, Aug 21, 2009 at 6:01 PM, <cobram at juno.com> wrote:

>> A single temp sensor can kill the car and strand you where you sit? Wow,
>> I guess it wasn't just the motto they dropped, "Vorsprung durch Technik"
>> indeed. Even the lowly POS Kia would still run, it reverts to a default
>> value when sensors are out of parameter.

Brett noted:
> My folks' Volvo 960 has this exact failure mode for the engine coolant
>temperature sensor.  Instead of failing to the hottest temperature
> value like the Motronic in the 3B/AAN, it just shuts down.  The car
> dies- on the spot, and you can't restart it.  Left my mother smack in
> the middle of the busiest road in town, and a couple of people had to
> help push the car out of the way.


The thing is that it's entirely possible/probable that the sensor isn't 
failing completely (the article doesn't say failed sensors, it says faulty 
sensors). By the shear volume of cars affected my bet is that a run of 
sensors was made with the wrong or an innacurate thermistor. It's resistance 
curve would be off in a way that it reads a plausible value, but not the 
correct value. A computer has no way of telling the differance between the 
two. My guess would say that in traffic the trans gets a bit hot and the 
sensor is reading as being way too hot and dropping it into an overheat 
shutdown failsafe mode.

Of course thats pure speculation and although it makes perfect sense to me 
it could be just completely wrong too.

-Cody Forbes