My question is about code 23 what posible sorces sould i look for to remidy this code. I have a 91 305 tbi engine. I found my air temp sensor to be on the exaust manifold and slightly melted, i cleaned it up and reset the code. the check engine light used to come on under exeleration after driving for about an hour, now it will pop up on idle after me relocating the sensor. I have a new sensor odered from gm but do u guys think i should check anything else, the tip with the two wires on the sensor are still intaced, so besides the sensor do u guys think i sould look for any other posible sorces of this code and if so what sould i check out. thanks guys

 

BPA,

The DTC 23 on your ECM is for a failure of the MAT sensor - "Low Temperature Fault". This means that the MAT/IAT sensor is reporting an impossibly low temperature, or a resistance reading in excess of 100,000 ohms. Either you are parking your car in temperatures below -40° or you have a connection problem in the MAT circuit (open circuit). Check the wiring, including the ECM grounds. I'm guessing you have a broken connection somewhere, and the melted wiring isn't a good thing.

BTW - This sensor input is required for the ECM to do its job, but isn't as critical as most other sensors. This is one place where it isn't imperative that you use an OEM GM replacement part, since "close" is good enough for this input. You may want to visit your local parts store and get a replacement connector for the sensro to solder into the harness. The MotorMite part number for the connector socket is 85100. They're about five bucks.

 

Thanks for the info it was very informative i apreciate it greatly.


Brian

 

28 bucks and a stop by the dealer down the street and no more code today! wish i had read the auto zone deal before i ordered the sensor but thanks vader.