Hi, need some help regarding the Motronic 2.7 system on a '94 Ferrari Mondial T.

The vehicle is fitted with an exhaust temperature sensor. Ferrari part number 142581.

One of the wires goes to the engine ECU.

My question is; what does this actually do to the ECU? Does it change the timing? Does it do anything? Is this connection needed?

I've included the wiring diagram and key. The exhaust temp module connects to the Motronic ECU on pin 52

We don't have diagnostics for this ECU. I haven't checked the flash codes as the fault light is off.

This is a V8, and has one Motronic system per bank. It has catalyst with before and after lambda sensors.



The exhaust gas temperature sensors are separate from the ECU. The instrument panel has 2 warning lights per bank. 1x engine warning light, and 1x exhaust temp warning light.



The exhaust temp warning light for bank 1 is always on. I've swapped the two units over, and the fault moves sides, meaning the control module is at fault.

Now my dilemma; this control module with part number 142581 is no longer available. We can still get the older module with part number 141037, but this has 3 wires rather than 6. This was fitted to the older Motronic 2.5 systems. As far as I know this just put the light on the dash, and that was it. I'm wondering if I can just retrofit the older one?

I've included the wiring diagram for the Motronic 2.5 system

It's not that easy unfortunately. The ECU has a 3 pin connector for diagnostics. I've managed to pull a code from one of the ECUs, of 1444. I can't find any info on flash codes for this model, but I think it means no faults found.

Can you expand on this?