help! air temperature sensor
03-25-2004, 02:03 PM
#1
help! air temperature sensor
my check engine light has been on for several months. i ran the self diagnostic and pulled code for intake air temperature sensor and the knock sensor. In regards to the air temp sensor, could it have anything to do with my frankencar intake that was installed about 6 months ago. Also, could the two sensors be related. I have a 1997 Maxima with 120,000 miles. the air temp sensor from my local nissan is $35 but carparts.com has one called ambient aire temp sensor for $16. Is this the same part? Also, if anyone knows a good deal on knock sensors please let me know. The best price I found is about $140.
03-25-2004, 02:36 PM
#4
0401
Diagnostic Trouble Code 0401 points to a problem with the Intake Air Temperature Sensor. The IATS is mounted in the engine air intake duct, downstream of the air cleaner filter. It detects intake air temperature and transmits a signal to the Engine Control Module. The sensor uses a thermistor, a resistor with a value which is inversely proportional to temperature. The IATS is not directly used to control the engine. It is used only for diagnostic purposes. Therefore the engine should start and run normally, even with the Malfunction Indicator Light on and DTC 0401 stored.
This malfunction is detected when ...
a) An excessively low or high voltage from the sensor is detected by the ECM.
b) The signal from the IATS is inconsistent with the signal received from the Engine Coolant Temperature Sensor.
Possible causes include ...
- Harness or connectors (The sensor circuit is open or shorted.)
- a faulty Intake Air Temperature Sensor
The IATS resistance values should be ...
- at 14 degrees F, 7.0-11.4 Kohms
- at 68 degrees F, 2.1-2.9 Kohms
- at 176 degrees F, 0.27-0.38 Kohms
For further information about the Intake Air Temperature Sensor please refer to the Chilton repair manual (page 4-16) or the Haynes repair manual (page 6-11).
Knock Sensor info in FAQ's and How-To's
Diagnostic Trouble Code 0401 points to a problem with the Intake Air Temperature Sensor. The IATS is mounted in the engine air intake duct, downstream of the air cleaner filter. It detects intake air temperature and transmits a signal to the Engine Control Module. The sensor uses a thermistor, a resistor with a value which is inversely proportional to temperature. The IATS is not directly used to control the engine. It is used only for diagnostic purposes. Therefore the engine should start and run normally, even with the Malfunction Indicator Light on and DTC 0401 stored.
This malfunction is detected when ...
a) An excessively low or high voltage from the sensor is detected by the ECM.
b) The signal from the IATS is inconsistent with the signal received from the Engine Coolant Temperature Sensor.
Possible causes include ...
- Harness or connectors (The sensor circuit is open or shorted.)
- a faulty Intake Air Temperature Sensor
The IATS resistance values should be ...
- at 14 degrees F, 7.0-11.4 Kohms
- at 68 degrees F, 2.1-2.9 Kohms
- at 176 degrees F, 0.27-0.38 Kohms
For further information about the Intake Air Temperature Sensor please refer to the Chilton repair manual (page 4-16) or the Haynes repair manual (page 6-11).
Knock Sensor info in FAQ's and How-To's
03-25-2004, 04:52 PM
#5
Did you install the Frankencar yourself or did you pay someone? If someone else did it they probably unplugged it and tossed it instead of relocating it in the Midpipe. Cheap shops cut corners like you wouldn't believe. What do you mean just falty? It is the only sensor on the intake plumbing besides the MAF. It has two screws in it and it should be connected with the midpipe. If it is laying in your engine bay I doubt it would throw a code but you should spend the time to mount it on the intake. If it is connected properly you have a bad sensor and I would suggest getting one from Nissan. It always seems that I get ripped off at Nissan. I got mine last weekend and it was $59
03-26-2004, 11:54 AM
#7
i installed the frankencar intake myself. The sensor is still in the plastic tubing which would be right before the stock air box. If I have to relocate it to my mid pipe, how would i connect it? it doesnt look like there is any holes that i could put it in. If I dont have to move it then maybe it just needs to be replaced.
03-28-2004, 04:45 PM
#8
It will work to have it laying in the engine bay but it won't be extremely acurate. Being in the midpipe it would be able to read what your engine was actually recieving and thus not throw a code as easily. To install in on a Frankencar type midpie you have to drill three holes into it. One for the sensor and two for the screws that hold it in. Be careful not to break the resistor and be sure to use some type of sealant otherwise your will have an intake leak.
03-29-2004, 08:23 AM
#10
Sup,
My CEL came on yesterday and I checked the code. During the day while I was driving, I noticed the my foot was getting warm. I was thinking maybe I was driving a bit fast (~80mph), but that never happen in the past. That was odd.
The next time I started my car, my CEL came on. It spitted out the code 0401 Intake Air Temperature Senor. Now I'm thinking the IATS was the cause. I'm planning to get the parts and replace it.
My CEL came on yesterday and I checked the code. During the day while I was driving, I noticed the my foot was getting warm. I was thinking maybe I was driving a bit fast (~80mph), but that never happen in the past. That was odd.
The next time I started my car, my CEL came on. It spitted out the code 0401 Intake Air Temperature Senor. Now I'm thinking the IATS was the cause. I'm planning to get the parts and replace it.
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