Coolant Temp sensor weird data

[VB Owner]

Hi all,

I suspected my coolant temp sensor was faulty on my VX Berlina series 2, 2002 model.

I unplugged it and checked the temp reading via the cluster and it reads 40 degrees C dead cold.

However I plug my scan tool in and it reads -40 degrees farenheight.

Am I missing something here, or is my ecu buggered ? If someone can enlighten me it would be awesome.

Cheers Ben

 

[Immortality]

40°C can't be dead cold unless it is -40°C ?

Does your scan tool have an option to change from °F to °C?

 

[07GTS]

most temp sensors default to -40c when unplugged

 

[VB Owner]

No the scan tool is only in farenheight unfortunately. However shouldn't the temp on the car cluster and scan tool match ?

Bit odd for sure.

 

[Immortality]

What engine does your VX have?

Most OBD2 scan tools aren't compatible with the V6 engines as they use the older ALDL protocol which may explain the difference.

 

[VB Owner]

Its a V6 stock engine. The scan tool is a Vident i730 Pro capable of both ALDL and OBD2.
I also have Envyous customs advanced and it shows the same results ?

 

[VB Owner]

I guess I'll put it into a different light. Forget about the scan tools. If I was to unplug the coolant temp sensor and accessed the 'special modes' on a Berlina, the temp should be zero correct?

 

[07GTS]

I guess I'll put it into a different light. Forget about the scan tools. If I was to unplug the coolant temp sensor and accessed the 'special modes' on a Berlina, the temp should be zero correct?

post #3

 

[VB Owner]

Thanks, sounds like a bad ecu then

 

[RiffRaffMama]

Fun fact: Coolant temperature sensors only work properly when there's coolant for them to measure. If your radiator has suffered a sudden catastrophic loss of coolant while driving (and you can't see it, because, you know, you're driving...), the display will read a healthy temperature and you'll get around completely oblivious until your car starts to make horrible noises and you find yourself on the side of the Princes Freeway in Werribee at night with a blown head gasket. Or so I've heard *cough*.