I was idling at a light and my ses light popped up and I used auto exray to scan it and see what it was.. it says code 23 MAT sensor too low. I looked at the manifold temp on the scanner and it constantly reads -40.0*F.. I rewired the harness and put a new sensor in it and im still getting the SES light and the -40.. I dont understand this. The ses light seems to only come on at idle. But ont he scanner no matter what it ALWAYS says -40.0*F.. Anyone have this problem before? Oh and the re wiring I did was on the IAT sensor because when I went to GM they said code 23 was IAT. I check the OHM resistance on the wires and it was around 1.5 and before the rewiring it was .7665 or something. Thanks in advance


Nick
CountryMuzicZ28.. (under robbyrobs name)

 

anybody??

 

If the scanner is showing -40degF for the IAT sensor, you have an open circuit. That is the temperature you get when the resistance of the IAT sensor exceeds 100,000 ohms.

Did you pull the connector off the sensor, key on/engine off, and get +5V across the harness wires?

If you used an LT1 specific list, like the one on Shoebox's page, you would have got:

Intake Air Temperature (IAT) sensor circuit (signal voltage high, low temperature indicated)

MAT is the same thing - Manifold Air Temperature. That's what GM used to call it. Same sensor.

 

I figured it out.. I checked the wire right before the connector and it was 1.591 ohms and thats apparently what i need and atleast i got a reading.. I checked the connector and no signal, the wire was apparently broken inside and wasnt making contact.. Where can I get another connector??

 

Part numbers for replacement pigtails. You also might be able to find a cheaper replacement at your local auto supply.

 

THANKS SHOEBOX!