Intake temp sensor wiring help!
Thread Starter
Drifting
Joined: Feb 2008
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From: Port Charlotte FL
Intake temp sensor wiring help!
Hey guys my plug on the intake temp sensor broke, so I ordered a new pigtail for it. My question is the new pigtail has a yellow and black wire (I'm assuming yellow will be the positive), but which wire on the stock plug is positive and negative? Does it even matter, I'm sure it does so I'm making sure I don't wire it backwards... Thanks guys! 
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
Hey guys my plug on the intake temp sensor broke, so I ordered a new pigtail for it. My question is the new pigtail has a yellow and black wire (I'm assuming yellow will be the positive), but which wire on the stock plug is positive and negative? Does it even matter, I'm sure it does so I'm making sure I don't wire it backwards... Thanks guys!
For the factory connector, pin A (purple wire) which is sensor ground from the PCM. Pin B (tan wire) which is 5 volts from the PCM.
Tech Contributor
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From: Dyer, IN
Race Director
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From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Meh, that's what I get for going off memory....
But regardless, the sensor is still not polarity sensitive. current can flow in either direction through it, so it does not matter which wire is which at the sensor.
The Intake Air Temperature (IAT) sensor contains a semiconductor device which changes the resistance based on the temperature (a thermistor). The IAT sensor is located in the air intake passage of the engine air induction system. The IAT sensor has a signal circuit and a ground circuit. The PCM applies 5.0 volts on the signal circuit to the sensor. The PCM monitors the changes in this voltage caused by changes in the resistance of the sensor in order to determine intake air temperature.
When the intake air is cold, the sensor (thermistor) resistance is high. The PCMs signal voltage is only pulled down a small amount through the sensor to a ground. Therefore, the PCM senses a high signal voltage (low temperature). When the intake air is warm, the sensor resistance is low. The signal voltage is pulled down a greater amount. Therefore, the PCM senses a low signal voltage (high temperature).
When the PCM senses a signal voltage lower than the normal operating range of the sensor, this DTC will set.
When the intake air is cold, the sensor (thermistor) resistance is high. The PCMs signal voltage is only pulled down a small amount through the sensor to a ground. Therefore, the PCM senses a high signal voltage (low temperature). When the intake air is warm, the sensor resistance is low. The signal voltage is pulled down a greater amount. Therefore, the PCM senses a low signal voltage (high temperature).
When the PCM senses a signal voltage lower than the normal operating range of the sensor, this DTC will set.
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
Thread Starter
Drifting
Joined: Feb 2008
Posts: 1,454
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From: Port Charlotte FL
okay thanks for all the info, I am running a twin flow polished intake... The wires were fragile on mine seeings its a 97' and i ripped them out the clip by accident. Did the best I could to try and repair the clip, but I'm guessing it wasn't good enough.
