Technical How many coolant temp sensors on 2008 Fiat Ducato x250 3.0L

[chrsfrm]

Hi guys
Struggling with my non-moving temp gauge. Was OK, did some engine work, now not working. Obvious thought was I had dislodged a connection. Much searching only found one sender, below turbo pipe. Tested, seemed ok but replaced anyway. Still not working, no MIL on. Tested new one, all OK for resistance and changes with heat. Also continuity and one terminal to earth. Other terminal provides 5v with key on. I cannot find a second (gauge only) sensor unit. Does anyone know if there is only one or the position of a second? Very frustrated now. Thanks.

 

[Anthony489]

Hi chrsfrm

I an 99% confident that unlike previous generation engines, there is only one sender (NTC thermistor) with a Blue/Black Signal wire to Pin 58 of Engine ECU connector M01B, and a Grey/Red wire to Pin 41 for the reference Ground. The sender is electrically floating i.e. doesn't rely on a connection via its threaded mount. With the sender disconnected, seeing +5V from Pin 58 sounds believable. With the sender connected it will be a lower voltage depending on temperature.

Presumably temperature data is communicated digitally from the Engine ECU to other places like the instrument panel. Others have complained of instrument needles mechanically sticking after a period of non use - maybe worth a check ?