A few weeks ago my CEL light came on and gave me the IAT (intake air temp) sensor code. The CEL came on right after I hit a big bump in the road on a super cold day so I figured it was just a glitch. I checked the harness and then cleared the code with my OBD II scanner. A week later I hit another big bump and the code was thrown once again. I got home and checked the sensor with a volt meter. The reading was non existent. On my ODBII scan my intake air temp was registering -40 degrees in my garage which was probably 40 degrees at the time. I pulled the sensor to inspect it. It turns out that the temp sensor element broke away from one of the two prongs. How this happened I don't know. I broke out my solder gun and fixed it then tested the IAT per the instructions in the Nissan FSM. According to the readings, the IAT was a bit slow to react and was a little off. I reinstalled the sensor and the temp readings were a more accurate 38 degrees. My gas mpg went from a consistent cold weather 19mpg to consistent cold weather 21mpg. The car also feels far more lively. I did some experiments with the IAT by unplugging it with the motor running and the OBD scan running. The code would not get thrown. I also started the car with the IAT unplugged and no codes were thrown even though the OBD scan was showing -40 degrees at the intake with the IAT unplugged. A code did get stored as a code pending. It appears it takes a good bit of driving for the code to be thrown. -40 degrees seems to be the lowest reading the ECU recognizes. If the ECU thinks the temps are -40 degrees and it's 40 degrees outside, the car is going to run super rich prior to warm up and possibly overly lean once warmed up possibly causing detonation. This sensor does have a function.

This week I went and ordered a new IAT so that the car is getting the correct readings.


Dave