Okay...after installing the power wire this past Sunday, and running for a couple of days, I get a P0111, IAT sensor performance. I'm gonna pull the power wire and see if the code clears by itself. Any other ideas? I bet this ends up being the problem though. Any one else with a power wire have this issue?

Yes, when the outside temp. is much over 90, it will do that. I remove mine in June, and put it back in Sept.

Aha!! I did not know that. That is good info to know as temps have been in the upper 90's to 100 here.

Thanks!

I run mine year round and never had that code, was 96 yesterday

I'll double check all of my connections tomorrow and go ahead and reset the PCM and see if comes back, then pull the wire if it does and see if comes back again.

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I run mine year round and never had that code, was 96 yesterday

These trucks are all individuals. The same mod can effect a similar truck differently. Notice his an mine are 03's. A good example of this, is the 180 thermostat. Some throw a code, some don't!

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Originally posted by Superjay:

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I run mine year round and never had that code, was 96 yesterday

These trucks are all individuals. The same mod can effect a similar truck differently. Notice his an mine are 03's. A good example of this, is the 180 thermostat. Some throw a code, some don't!

I will give ya that, all the trucks are individual.But in the same context I have never heard of anyone throwing that code runnin the power wire till now, could be an '03 thing.

As far as the 180 t-stats the only ones I see throw the code are the jet and the mr. gasket and there is a perfectly good explaination for this. The 2 above mentioned don't have the blocker like the original and don't allow the proper time for the coolant to reach operating temp. If all the guys runnin the 180 used the stant 14168 I highly doubt we would see as many threads for that code, because that t-stat has the blocker just like the factory 205.

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I have never heard of anyone throwing that code runnin the power wire till now, could be an '03 thing.

There have been some posts in the past. Mine has done it from the get-go. It will also do it under 35 degrees.

That's weird, I've had one on my 07 for probably a year and a half. It's seen 110 degrees and as low as 25 and never thrown a code.

The bigger question is, how/why does the 03 ECM know it's getting a bogus reading. What is it comparing it too?

Not sure about the '03s, but this is what the '05 factory manual says.

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P0111-INTAKE AIR TEMPERATURE SENSOR RATIONALITY (CONTINUED)
For the Engine System Schematic circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W.
Theory of Operation
Intake Air Temperature Sensor performance looks at the outputs of three temperature sensors and compares them
under cold start conditions. Following a start to run delay time, the outputs of the ambient, engine coolant, and
intake air temperature sensors will be compared. If the engine coolant and ambient air temperature sensors agree
and the intake air temperature does not agree, the intake air temperature sensor is declared as irrational.

* When Monitored:
The engine off time is greater than 480 minutes. Ambient Temperature is greater than 4 deg C (38 deg F).

* Set Condition:
After a calibrated amount of cool down time the PCM compares the ECT Sensor, IAT Sensor, and the Ambient
Air Temp Sensor values. If the IAT Sensor value is not within 10 deg C of the other two temperature sensors.
Two Trip Fault. Three good trips to turn off the MIL.

Good find Dave. Unfortunately it raises more questions than it answers.

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Unfortunately it raises more questions than it answers.

Yep. Good solid, understandable info is hard to find on a lot of DTCs.

Once I get my server PC back up and running at the house, I'll check the 03 DRM and compare it to the 05 excerpt posted a couple posts back, but I'd bet they match. We'll see....

So far, all of the diagnostic info that I have read for this code all says basically the same information regarding the 480 minute cool down and temp check amongst all three sensors. Now the only thing that I can think of is that 10 deg celcius is equivalent to approx 18 degrees farenhiet. If the the 4.7k ohm resistor really does drop the sensed temp at the IAT 20 degrees, then that would explain the P0111. The IAT would be measuring 78 degrees when the other two sensors are seeing 98 degrees. However, this still does not explain why the 03's would have the problem when 04 and up don't. It would also seem to me that if this were the case, if you live in an extremely cold climate and run a block heater in the winter, then you would see this code all of time, but it would be and ECT code, not an IAT code. Apparently, the ECM only uses the comparison of temps between the IAT, ECT and the ambient air temp sensor to verify whether or not all of the sensors are functioning properly and only after an 8 hour cool down. Looks like to me that the 4.7k ohm resistor does drop the sensed temp 20 degrees.

I did a little checking and probing with a VOM and found that I had good connections all the way thru the resistor and connectors thru the IAT connector as well. So, I went ahead and pulled the power wire out and reset the PCM. Virtually same conditions and driving habit and no CEL for the past two days.

Another thought that has just popped into my head is that this would explain to me why CAI work like they do. Since the IAT senses cooler air coming in, it lengthens the injector pulse, thus richening the mix and giving the feeling of more power. The difference is that you actually have cooler air coming in with a CAI, and not just fooling the PCM into thinking it's cooler air. I guess I am going to get rid of the power wire and throw on a CAI. I can't stand having the CEL on no matter how minor the code is. Or I may have to buy some vaious resistors and experiment a little. I'm sure thought, that this would come to a point where it wouldn't be worth it, but there's only onee way to find out, huh?