13 Ram 5500 - low power and P0106

cbriggs · March 22, 2019

Hoping for some insight from some of you more experienced with The 6.7 cummins in the above truck. It belongs to a good fleet customer of mine, their fleet is primarily ford, but they recently bought this unit as their service truck. It came in with a P2580 for the turbo speed sensor, a P0106 for a Map fault, A P2227 and one more code I cant recall right now ( something about NOx exceeded, egr disabled). I have replaced the turbo speed sensor and map sensor at customers request. On a cold start it sets P2580 and I can verify with scanner data that it runs about 5 seconds before turbo speed registers anything, after that it seems to read fine, although I have no reference data on what it should read during different operating conditions. When driving it generally feels gutless compared to a similar equipped f-550. (it weighs around 18k lbs) and after about 2 or 3 minutes of driving it sets a P0106 and goes into limp mode. I can watch some data on my snap on solus, the MAP sensor and turbo speed sensor are working when the code sets, but my max boost is around 18 - 19 psi WOT acceleration, with the codes cleared. I'm thinking it should be more in the 26 to 30 range? There are no boost leaks that I can see or hear. When I changed the turbo speed sensor there was some oil and crud in the sensor cavity, I ran across some info online that suggests that means the turbo is junk, but it is not from a verified source. Can anyone verify that? I'm thinking turbo but its a 7K job, so I don't want to be wrong. Any ideas?

JoeR · March 25, 2019

Cummins is big about putting substituted scanner readings on failed sensors. The delayed reading makes me thing that's the problem. Grab a lab scope to check the turbo speed sensor. My bet is that there's no signal.

P2580 takes a minute or so to set, but the engine has to be spooled for it to set. The fastest way to do it is to hold it at WOT in park for 60 seconds.

The P0106 is almost certainly caused by the bad Turbo Speed Sensor reading.

Joe

cbriggs · March 31, 2019

Looks like it was caused by the inlet pressure/ temperature sensor (in the clean side of the air box). Sent it to ram dealer, the only code they got to consistently reset was a P2227. They called the inlet pressure sensor, but didn't have one. I ordered and replaced it and was unable to get any concern to reproduce. Got 29.5 psi boost on a test drive, 10 psi more than I could ever obtain before.