Volvo 850 TDI, EFI 132 and 712 error codes

[Per Groth Ludvigsen]

I am struggling with the following problem for a couple of weeks now. When
engine is cold the temperature meter shows hot engine when ignition is put
on and the engine fan is also activated. Starting the engine the problem
persist but after approx. 2 minutes of driving the temperature meter shows
that engine is cold and from now on the meter shows that the engine become
warm normally. The error codes stored in the ECU is EFI 132 - engine
coolant sensor signal missing and EFI 712 - fuel sensor signal missing. I
have changed the coolant temperature sensor but that did not solve the
problem.
I can clear the codes and they do not return when engine is hot. The EFI
error's come again when the engine is cold when the starte ris activated. I
guess
that there is on open circuit from the coolant and fuel sensor to the ECU
input port when the engine is cold - but how can this happen and where
should I
search for the open circuit?

Cheers Per

[edas...@sonic.net]

if two sensors fail @ the same time, it is probably not a sensor. the
ecu is a possiblity, but they are fairly rugged. so, it's a junction.
w/o a yr i'm clueless. you can track down the fault as easily as i.
try the parts dept. @ a dealer. i'm thinking the connection @ the mas,
but what do i know?

[Per Groth Ludvigsen]

"Per Groth Ludvigsen" <p...@post.cybercity.dk> wrote in message
news:4d6c03b2$0$36584$edfa...@dtext01.news.tele.dk...

>Just for your information. Found the problem to come from the MSA 15.7 ECU
Edgeconnector, Pin A35, which is the Ground Pin to the coolant and fuel
sensor's
5 Volt supply. It was corroded/broken 2 millimeter above the soldering.
Fixed
it making a new soldering and now everything works fine.

Cheers Per