engine coolant sensor vs torque covertor lock up

been doing some work on my td5 how ever forgot to reconnect the cooling sensor ,,the next morning I'm driving to work I noticed the cooling gauge on the dash red light and reading zero ..I knew I forgot to reconnect sensor but to early in the morning to pull over so I thought I would just do it when I got to my local 7 eleven for my morning coffee

in the mean time I have noticed that torque convertor will not lock up when the engine coolant sensor is disconnected ...is this normal

I thought the TC would lock up once its knows the transmission temps are safe to do so

But then if the sensor that is disconnected and assuming its dual function and so also used by the gearbox ecu, how would the ecu know the temp?

Assume now u have reconnected the sensor things are back to normal.

There is no transmission temp sensor involved in the management, the one in the oil cooler is a temp switch which manages only the high temp warning, the transmission(EAT) ECU is addaptive and it monitors all the engine management inputs to select the most appropriate adaptive map for the prevailing conditions, an ECT open circuit means that the engine ECU limits the fuelling and works based on FT sensor inputs with limited power so the EAT ECU will behave differently with the lock up solenoid....
in a nutshell: what happened to you IMO it's normal

sierrafery said:

There is no transmission temp sensor involved in the management, the one in the oil cooler is a temp switch which manages only the high temp warning, the transmission(EAT) ECU is addaptive and it monitors all the engine management inputs to select the most appropriate adaptive map for the prevailing conditions, an ECT open circuit means that the engine ECU limits the fuelling and works based on FT sensor inputs with limited power so the EAT ECU will behave differently with the lock up solenoid....
in a nutshell: what happened to you IMO it's normal

Click to expand...

thanks
I was on the understanding that the transmission had its own temp sendor
the transmissions I work on obviously run a different management system

any ways its nice to know what symptoms can be caused with disconnected sensors

discool said:

But then if the sensor that is disconnected and assuming its dual function and so also used by the gearbox ecu, how would the ecu know the temp?

Assume now u have reconnected the sensor things are back to normal.

Click to expand...

it appears that the engine coolant sensor does play up with the transmission when I got to the 7 eleven I quickly plugged in the sensor every thing was all good
I knew I forgot to plug the sensor back in I needed to disconnect the sensor to get my arms a curtain place while doing another job and I didn't want to break any thing

while I was driving to work the next morning the transmission would not lock up ..I was thinking now my transmission or toque convertor may be stuffed or a duff solenoid
just wondering for those who don't have a diagnostic tool have purchased new parts for the transmission because of a engine coolant sensor breaking down

If you scan the EAT ECU you should find a "P1884(19)CAN message: Engine temperature invalid" fault code logged, this is one of those without M+S flashing protocol and the default for that is: "Substitute engine temperature derived from other inputs" in this case the FT sensor which being around 10*C lower the shift map is mixed up, maybe on a longer drive when the FT gets to around 80*C the symptom might not be so noticeable

sierrafery said:

If you scan the EAT ECU you should find a "P1884(19)CAN message: Engine temperature invalid" fault code logged, this is one of those without M+S flashing protocol and the default for that is: "Substitute engine temperature derived from other inputs" in this case the FT sensor which being around 10*C lower the shift map is mixed up, maybe on a longer drive when the FT gets to around 80*C the symptom might not be so noticeable

Click to expand...

come to think about it
gear changing up was jerky basically snapping through the gears

I might have to invest in a scan tool for the td5 as it will be good to learn the management system