IAT -38* then when jumped reads 285*
04-01-2012, 03:18 PM
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IAT -38* then when jumped reads 285* I was searching on here and read that when there is an open circuit, the IAT will read -38* and to check if the circuit is good, to jump the wires (I crossed them by the sensor). When I twisted them together, it read 284*. I believe this tells me that my IAT sensor itself is bad. But... I also read that when you have a bad IAT sensor that the car will run like crap. However, the cars starts very well and runs very well for not having a tune on it yet. Throttle response is pretty good and there is no hesitation or any indication anywhere of it coming even close to stalling out.
I checked continuity all the way from the pig tail all the way to the PCM on both wires and it is good. The tan wire (some PCM's it is purple) is sending 5v and the the black wire is grounded when I check continuity to ground.
The car behaves normally, but the reading of -38* bothers me a great deal. All other sensors seem to be reading normal. TPS reads 29% at idle, that seems kinda weird, but no worried about that yet.
any ideas?
3bar OS, E85
I checked continuity all the way from the pig tail all the way to the PCM on both wires and it is good. The tan wire (some PCM's it is purple) is sending 5v and the the black wire is grounded when I check continuity to ground.
The car behaves normally, but the reading of -38* bothers me a great deal. All other sensors seem to be reading normal. TPS reads 29% at idle, that seems kinda weird, but no worried about that yet.
any ideas?
3bar OS, E85
04-01-2012, 04:48 PM
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I have not done a TPS relearn. I will have to look into that as I do not yet know how to do that.
04-01-2012, 04:58 PM
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You need to fix it, because your engine is burning more fuel when in open loop, and it takes longer to enter closed loop operation.
Also, the airmass calculations and timing are skewed (lost efficiency).
To check if the sensor is bad, unplug the sensor and watch the IAT with a scanner, it should be -38 °C. Then short the 2 pins at the harness and it should read like 155 °C. If you get these 2 readings, then your sensor is bad.
You can use this table to check the sensor (you must know the temperature of the sensor tip)
Also, the airmass calculations and timing are skewed (lost efficiency).
To check if the sensor is bad, unplug the sensor and watch the IAT with a scanner, it should be -38 °C. Then short the 2 pins at the harness and it should read like 155 °C. If you get these 2 readings, then your sensor is bad.
You can use this table to check the sensor (you must know the temperature of the sensor tip)
04-01-2012, 05:21 PM
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You need to fix it, because your engine is burning more fuel when in open loop, and it takes longer to enter closed loop operation.
Also, the airmass calculations and timing are skewed (lost efficiency).
To check if the sensor is bad, unplug the sensor and watch the IAT with a scanner, it should be -38 °C. Then short the 2 pins at the harness and it should read like 155 °C. If you get these 2 readings, then your sensor is bad.
You can use this table to check the sensor (you must know the temperature of the sensor tip)
Also, the airmass calculations and timing are skewed (lost efficiency).
To check if the sensor is bad, unplug the sensor and watch the IAT with a scanner, it should be -38 °C. Then short the 2 pins at the harness and it should read like 155 °C. If you get these 2 readings, then your sensor is bad.
You can use this table to check the sensor (you must know the temperature of the sensor tip)
Thank you. I pulled the sensor out and measured the resistance. It is not reading anything. Just to make sure, I measured an injector and it measured 5 ohms like it was supposed too. I am confident the sensor is bad now.
