IAT Always Reads 32°

[CruelJung]

Earlier this year, I solved a cold start issue with my 2008 Yukon XL (5.3 LMG) by replacing my ECT sensor. I discovered a few other issues along the way to that fix and one of those issues is that my intake air temperature consistently reads 32°, regardless of environmental conditions or engine temperature. Installing a new MAF sensor did not fix this reading, so I’m presuming this is a problem in the connection between the MAF and ECU/PCM. No CEL, trouble codes, or obvious (to me) operational issues, but I imagine my engine would benefit from an accurate IAT read. The last thing I tried was a cheap cable tracer from Harbor Freight and that did not pan out for me.

Does anyone have any advice or experience with diagnosing/solving this problem?

 

[j91z28d1]

looks like it's pin D tan/black and E tan. at the maf and pin 38 tan and 37 tan/blk at the ecm.

if you can get to it might ohm put the wires at both ends.


with the sensor unplugged it should read across D and E

32deg 5119- 5892 ohm
68deg 2290-2551 ohm
104deg 1096-1238ohm
176deg 312-370ohm

might at least let you know if the part is OK before you start searching thru the harness