The temp sensor is new.

I hope you used an OEM sensor, not aftermarket.

I have never received such a message and I'm sure I have had my intake way hotter than 170*, pulling my 12K trailer up Arizona mountain slope, 110* or hotter outside.

At around 160 I get the "Reduced Power" (that has to be reset).

Is this a message on your DIC? How do you reset a DIC message? Do you get a check engine light?

 

A modest IAT rise is common in all vehicles, and the dmax fleet has been especially bad from the beginning of time. This truck has never been great at isolating underhood air infiltration into the intake. The worst case is when towing from stop light, to stop light after the truck has been worked. Part of the problem is fan rotation. When you stop, the only cooling air movement is fan induced. And the fan rotation dumps the heated cooling air over onto the intake. Once under way the vehicle movement dumps cooler ambient air into the intake opening.

 

Yes, I went with an aftermarket MAF sensor instead of the AC delco.
I have attached some pictures. So I was focusing on the temp because that is what I seen change the most. I monitored the MAF as well and nothing out of ordinary there.
Keep in mind, I have had this truck for years, after doing it the first time I changed the MAF ( which also has one of the temp sensors in it) sensor and I did not fix it.

 

I dont see where your CEL and limp mode is air temp related, as you stated. You have a MAF code. Possibly from a diagnostic test when the egr opens and closes. You should see the MAF strip chart fluctuating as egr opens and closes. Open egr will decrease MAF. It is straight lined from what I can see.

 

Thank you Charly. That picture with the graph was taken seconds after i got got the code. I replied to Ron's response after i read his attachment with the P0101. Thank you again for your time on assisting me.

 

Result: 43.09127515 gram/second = 5.7 pound/minute So you are possibly slightly high vs average of most trucks but that does not appear to be your problem, and Charley is right on target.

Does your scan tool capture information when a DTC is set by the truck? Looking at that info may help determine what is going wonky.
See the attachment for more information about P0101

 

Thanks again Ron for assisting. The picture in with the graph and temp was taken seconds after the check engine light/code came up. This may be the conditions that it is happening, from your document.

Looking at the document on P0101
So i get it with a high resistance reading.
When running at idle, normal range needs to be 10-20 g/s (i will try to find that reading and monitor on my scan tool)

"When engine coolant temperatures reach 60°C (140°F) the ECM commands a Rich Idle mode. During Rich Idle the exhaust gas recirculation (EGR) valve is commanded ON, and a lower frequency and g/s value will be indicated on the scan tool."
I could look at this as well when idling, haven't paid attention to engine temp and see what the EGR does.

• Diagnostic Aids A slight to moderate resistance of 10-20 ohms on the MAF sensor ignition 1 voltage circuit may cause this DTC to set.
• Certain aftermarket air filters may cause this DTC to set.
• Certain aftermarket air induction systems may cause this DTC to set. Modifications the air induction system may cause this DTC to set.
• A inaccurate MAF sensor, an intake air flow restriction or any unmetered air that enters the engine downstream of the MAF sensor may cause this DTC to set.
• An aftermarket exhaust system may reduce engine back-pressure excessively and cause this DTC to set

When it first occurred, i was out of town and replaced the air filter (to aftermarket & original looked dirty) and replaced the MAF (aftermarket) because i had a 10 hour trip ahead of me. Reading the above, I think i will work on eliminating those 2 items. Put my original back in with the new filter, then maybe go with a better air filter with each MAF and see if that changes it any...

Ron, will look into wether or not my scan tool captures multiple measuring points when DTC arises. I was sitting and waiting on the last one. It is pretty consistent, i just have to drive a while and then just sit and idle until code pops up. I am having issues getting my scan tool to connect to my app which might have more features.

Thanks again Ron for sharing your resources and knowledge.

 

Soon after I got my 2007 I started getting the P0101 code also. It would usually set while I was letting the engine warm up when first starting up for the day. I replaced the MAF with no luck and it was driving me crazy. As Charly said the P0101 is a maf code related to air flow to the engine. In Ron's attachment top of page 3 it says to check for a dirty filter. In my particular case my aftermarket filter was dirty and the maf saw reduced airflow. After I replaced the filter the code went away and has never returned. I'm still new to diesels and I learned a lesson about cleaning my aftermarket dry filter on a regular basis. Perhaps your issue could be as simple as changing your filter.

 

thank you, i replaced filter same day i replaced the MAF sensor and it came back that day.

 

When the ECM creates a DTC, the captured data is called 'Freeze Frame Data' Most scanners give you an option to look at that 'Freeze Frame Data'.

 

See captured freeze frame

 

In the graph, why does your maf reading disappear briefly? There is a self test AT STARTUP that tests the egr open and close. You can hear the self test as the note of the engine changes while the turbo vanes open and close to provide back pressure. Do you see the MAF strip reading change when that self test is happening?

 

Charly, i think the graph disappearing is because i took a picture of the screen and it didn't pick up that section (if you look close you can see the line faint), kind of like how it didn't show some letters on the dash. I noticed that too and then checked back and the graph remained the same bumpiness throughout. I will try the start up tomorrow when i crank it. I do know that when I put the truck in park to idle, the MAF reading goes down to 2, then after a few seconds at idle it goes back up to 5 range and stays around there even when code is thrown.