Dieselwrenches

What year/model/engine?

25 psi is very low on pulls. Should be getting 35 minimum on big pulls. Check cac, cac boots. What's exhaust temp.? Smoke? Codes?

If they will let you watch the temps, t1,t2 and t3, as well as dpf differential psi. That will give you a good indication as to any "regen" issues. T1 should get to around 600 to 650 give or take 50 deg. T2 and t3 should work towards 850ish, it's more important that the sooner they match and stay close to each other the better. Dpf differential psi tells you how much restriction that filter is causing. The lower the better, anything below .5psi during regen is fine.

You can take it for an extendeded test drive. The truck will attempt passive regen and if you get it hot enough then you'll find anything you would with a forced regen visually it with any codes.

Also check accessory relay(large solenoid relay in dash left of fuse panel) if it's original it may be losing connection at a higher temp.

Check connectors at back of dash. What year is it?

The biggest problem with injector cups are when they are improperly installed during a replacement and do not last.

Fuel pressure?? If you've never replaced unit pumps I'd replace all six, they are known for under fueling as they wear and age. No fuel no boost. It's expensive but worth it. DO NOT REUSE OLD UNIT PUMP BOLTS AND TORQUE ACCORDINGLY.

*flashed not flagged, my bad.

If they flagged from vmac online properly it should have loaded whatever software was set up for your truck as per vin. If the tech did not save and transfer saved data file correctly it could have reset some parameters. You can have a dealer run through settings and parameters to verify everything is set up correctly. Also, if there has been a motor swap then they could have flashed with incorrect software, this is also something dealership can verify on vmac online by looking at vin and engine serial #.

May be as easy as recalibrating pedal.

11's and 12's will definitely have conical cups. Plus will have less regen issues as well.

Verify module is receiving power. Any codes?

Which style engine brakes? Jacobs? Valve lash info will be on valve cover. Turn the motor over just like your cats. At bottom of flywheel housing remove small cover plate to watch for valve lash position settings. I.e. 1&6etc. Adjust valves for whichever cylinder of the two marked that are loose. Depending on Jake's there are different procedures for the actual adjustment.

Which style engine brakes? Jacobs? Valve lash info will be on valve cover. Turn the motor over just like your cats. At bottom of flywheel housing remove small cover plate to watch for valve lash position settings. I.e. 1&6etc. Adjust valves for whichever cylinder of the two marked that are loose. Depending on Jake's there are different procedures for the actual adjustment.

If you don't have stalk on right side of seeing column to control screen you need scan tool our dealer software.

If you can check air manifold temp sensor. If it's faulty it reading incorrectly it will tell ecm to keep fan on as a precaution.

Just as a heads up. Intake air temp sensor reading wrong or faulting will cause fan to stay on all the time as well. That's an easy check.

If wiring and sensor are good. Wipe a small amount of grease on air filter housing and close hood. Don't slam hood just set it down and set latches. Open the hood and see if seal is pressing up against hood. If not adjust air filter housing to make a good seal. If there is not a good seal your engine will be taking in hot air from around you motor not cool air from outside hood.

Calibrate turbo, replace actuator if still a problem, make sure and turn your vanes by hand with actuator disconnected and make sure they move freely what turbo it's bad. Replace ecm as last really and if possible use test ecu.

What kind of Jake's?

Inlet won't read ever to laptop. Sensor won't read until they are at a certain temp anyways and 510 is max reading which is fine during a regen.

Look for a two wire sensor similar, jump the connectors and see if park brake light changes.

High speed is j1939, that is the twisted yellow and green wires.

Unless you've had the actuator of yourself or anyone else and it didn't get calibrated before going back on code is most likely because of sliding ring sticking and not moving freely in turbo due to dot build up or debris, you can tell by unbolting actuator and turning sector gear on turbo. Should move freely not bind up. After removing actuator it will need to be recalibrated with dealer software.