MIL Code Confusion

When you get a MIL code 23 on a van with the 4 cyl engine it means you have a problem with the Intake Air Temp (IAT) sensor. What does it mean if you have a 6 cyl engine that has no IAT sensor and you get a MIL code 23? The code lists I've found don't reference 23 to a 6 cyl. engine yet this 99 GV with the 3.3Ltr 6 is getting a code 23. Why and what does it mean?

Another mystery. Why would you get a MIL code 23 then only get a P1491 with a scanner. MIL code 23 equates to a P0112 or P0113. Can anybody clarify? Please! :banghead:

For the whole story read thread titled "incoming air sensor" by kroman

the code is as you suggest , 23 is IAT related . 1491 or MIL 35 code is an open or shorted low speed radiator fan relay control circuit , per factory manual..

Yes, MIL code 23 is IAT related but, it only applies to a 4 cyl engine. I'm dealing with MIL code 23 on a V6. The V6 does not have an IAT sensor. So...what does a MIL code 23 tell you on a V6? Should I concider it a bogus code or is it valid?

Furthermore, if you pull a MIL code 23, logic tells me you should pull a P0112 or P0113 with a scanner. A P1491 and only a P1491 pops up. Why?

Thanks for the response. I'm hoping the six charts I've looked at are just old code charts that aren't updated. If anybody has the answer please include a link to a chart or whatever referense you have if you can.

99 GV 3.3 ltr.