S80 water temp problem

[RaceCommo]

Anyone ever had o problem with sensor voltages? Wiring loom is tested and it's ok, tried other sensor and it didn't work either.

Problem started when engine wasn't running, shut down the power and turned it back on. Sensor mV shows 0mV.

Is this a ECU problem or something else?

[katana]

Are ALL the sensors showing 0v? that would point toward an ECU or a connector pin issue. If the others are reading correctly then assume a broken wire?

[RaceCommo]

Are ALL the sensors showing 0v? that would point toward an ECU or a connector pin issue. If the others are reading correctly then assume a broken wire?

Everything else is working fine. Have to check wires again.

[stevieturbo]

Ive never really looked at the raw voltages.

But Ive also never had an issue with the sensor reading.

Not sure which way about it would be, but either 0v or 5v would have to indicate either open circuit or short circuit.

[ignitionautosport]

if temp sensors are reading 0V then possibly blown 5V rail or pull-ups, if they read 5V then it's missing the 0V.

[RaceCommo]

if temp sensors are reading 0V then possibly blown 5V rail or pull-ups, if they read 5V then it's missing the 0V.

Its reading 0V.

[katana]

So this sensor only has a reading of 5v on one pin and 0v on the other ie. between pin and ground?
If the 5v rail had gone - no other sensor would be functional.
Multiple sensor failure - possible but unlikely so pointing toward wiring?

[stevieturbo]

Are you reading the voltage on screen, or via a meter ?

[lumley32]

temp inputs are pulled to 5v via a 1k resistor, if there is nothing connected to the pin it will read 5v in the software. take the pin out of the connector and check the voltage with DTASwin, if its not reading around 5v there is something wrong with the input, otherwise its a wiring fault!

[katana]

temp inputs are pulled to 5v via a 1k resistor, if there is nothing connected to the pin it will read 5v in the software.

I'm no electrical guru so can someone who is - explain that statement?

My understanding is ECU spits out a 5v feed to sensors which are generally 2 pin resistance types and earthed via their bodies to ground? So feed 5v in against sensor variable resistance and output on the remaining pin is a variable voltage of 0 - 5v? back to the ECU.

Who or what is getting pulled where and by what, to achieve what result?