Freightliner Cascadia Started Getting Check In When Goes Up The Hill

He had to have sensor that read def injection pressure replaced. Have it checked for faults in your dpf system.

Sounds like my 2015 Cascadia. Turned out that they needed to install a "DEF Tent (?)" in the system. DEF was vaporizing and crystalizing on the inside of the DEF system box. Three visits to shops and two tows to resolve it.

Good luck. After treatment issues suck.

Sounds like a DEF issue to me as well. Sounds like it needs a regen, then regent while driving on flat ground.

I have a six mile hill I go up at least once a week. If I go up it close to 80K gross, I have a 50% chance of having to do a regen.

Have you checked the diagnostic screen on the dash?

I am bumping and updating this thread because I am having the same issue.

Check engine lights were intermittent. Then last Saturday two check engine lights came on and I lost almost all power. I could go about 5 mph up any sort of inclide. Stopped, turned truck off and back on, and had power for the rest of the day.

Next day, no power again. I could get it to the dealership using side roads because I was bobtail. But still only 35 to 45 mph on level ground or downhill.

The codes triggering were MCM (motor control module) fault codes 4374 3659 3661. They replaced the MCM and did some other "recall" software updates and I'm on my way.

Delivered my load on Wednesday and got another load going to the port in Savannah, Georgia. Going through Atlanta, right in the thick of traffic on I-75 at State Highway 5, I lose power again going up hill. I limp it off on that exit where I pull off to the side. I put on my four ways, turn off then restart the truck. Now I have power again. I get back onto I-75 heading south. Debating whether I should take the chance to roll or stop at the Petro at exit 12. The truck made the decision for me. Lost power again and limped off at US 78. Crawled to the Petro.

Next morning crawled (many times only 5 mph) to the Freightliner dealer here. They're saying the fuel injection harness is short circuited. Waiting to hear if they have the part. If not, I'm here until Monday.

I will update as to the final resolution.

Ouch, Peach State has a large network of dealerships in the area so hopefully one of them will have it.