I have an 03 Cummins that was originally a Canadian truck and I have drove other 03's and my WTS light seemed to not be staying on for the right amount of time, it comes right on and stays on for about 4 dings the truck makes when you first turn the key and will start right up. Now the temperatures are starting to drop and when I went to start my truck the other morning it was about 42 degrees F but it is still only staying on for 4 dings and it still starts up but I know that it should stay on longer than that with it being cold because when it was 92 degrees out it was staying on for 4 dings so I know that with it being 42 degrees it should be staying on longer so what would be my issue?  I have no DTC's

I would guess your IAT sensor is stuck reading cold.   

 

I don't know much about 3rd gens but on a second gen the WTS light stays on only for a split second when it is warm.  

Get a live data tool like the OBDLink or ScanGauge II and check the ECT sensor and the IAT sensor at your first key on. They should both match in temperature. If not then you might want to replace the IAT sensor.

 

NOTE: Do not bother cleaning the sensor it will not change it's performance. That is an internet myth. 

It could be a temp sensor issue, or it could be different software. It's likely the software is the same but it's a possibility. 

 

The ultra gauge is good and inexpensive. 

 

 

EDIT: I pulled up seveal of the 03's in UDC Pro and they all have a pre-heat time of 10 seconds between 15° and 66°F. 

 

The label says ambient temperature, which is taken with the sensor on the air filter housing. I have also heard they use MAP sensor temp. 

Edited November 5, 20168 yr by AH64ID