Re: GM CTS sensors & MAT sensors

[Peter Gargano <peter@techedge.com.au>]

Shannen Durphey wrote:
> 
> I copied these tables because they actually showed slightly different
> values.  In almost all cases that I can remember, the charts for CTS
> and IAC have been identical.

This is quite interesting. After Bruce pointed out there was an IAT 
table at:

  http://syty.org/d&e-code23.html from  http://syty.org/diagnostics.html

I realised my JE Camira factory service manual had the same information,
so I looked, and there's the exact same table for IAT and a quite similar 
one for CTS, 

However, on the CTS diagnostic page there's a warning ...

!       NOTE: This resistance value table
!
!                 IS NOT THE SAME 
!              AS FOR THE MAT SENSOR.
!
!       They have different resistance-to-temperature values.

And similarly there's a warning on the MAT sensor diag page too!

So, I can only think that GM wants to create the illusion that IAT and CTS
sensors are different so that people don't try and interchange them. Perhaps
because they have quite different thermal properties, (but almost identical
temperature properties). This also gets back to the discussion about 
placement of the IAT and how quickly it really responds to ambient conditions.
Perhaps the smaller thermal lag of the CTS is the major difference between the
two sensor types?

regards, Peter.

PS. is this new?  http://diy-efi.org/gmecm/component_info/sensors.html
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