circuit to use GM temperature sensors for voltage based data

[Ludis Langens]

rr wrote:
> 
> The coolant & iat/mat sensors are thermistors. Just use a pullup to
> 10 volts with the other end grounded. GM uses both a 1K & 384
> ohm pullup. The ecm will change it for greater or less resolution.

The 1K is used when the ECM doesn't switch the pullup for better
resolution.  When it does switch, it switches between 4K and 348.

The IAT/MAT always/(usually?) is just a fixed 1K.  Some old cheap ECMs
also use a 1K on the CTS.  Newer and full featured ECMs do the 4K/348
switch.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/


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