scr warmup

[Mudflap77]

(08-24-2023 )onebadapple Wrote:  Hey Mudflap77 Had and now again having a similar problem. Search Rawze: “No lights no codes”. Had a cracked DOC under the heat shield. Fine for a year+. IT’S BACK! How did you fix it?

I just figured mine out a couple of days ago. Mine was the turbo intake temp sensor.
turbo intake temp should be roughly within 10% of the ambient temp. The ecm uses this sensor in part to calculate engine exhaust temp. My guess is if that sensor is reading high the ecm calculates the exhaust temp higher then it actually is and the ecm sees the DOC is reading lower then the calculated exhaust temp it figures its loosing a pile of heat and goes into scr warmup.

[Rawze]

(09-03-2023 )Mudflap77 Wrote:  ...just figured mine out a couple of days ago. Mine was the turbo intake temp sensor.
turbo intake temp should be roughly within 10% of the ambient temp. The ecm uses this sensor in part to calculate engine exhaust temp. My guess is if that sensor is reading high the ecm calculates the exhaust temp higher then it actually is and the ecm sees the DOC is reading lower then the calculated exhaust temp it figures its loosing a pile of heat and goes into scr warmup.

Actually one of its its secondary functions is used to measure/estimate turbo heat soak (how hot the turbo is getting).

[JimT]

Could you share part number(s) for the temp sensor(s) you discovered and turbo you have so others can compare? I'm curious to check my own turbo and according to your statement I won't be able to easily just look up the sensor's part number online.

[Mudflap77]

(09-04-2023 )JimT Wrote:  Could you share part number(s) for the temp sensor(s) you discovered and turbo you have so others can compare? I'm curious to check my own turbo and according to your statement I won't be able to easily just look up the sensor's part number online.

Certainly.
Turbo model# HE451VE
sensor P/N 4307110