ISX15 CM2250 IMAP sensor erratic, intermittent or incorrect

[zyNoT]

I also wanted to add that a fellow driver at a truck stop mentioned to me that he took his truck to peterbilt because he got freaked out when it prevented regens because of the derate code that eventually comes along with the codes I listed above if the problem isn't fixed in a timely manner. I will say this, peterbilt said he needed a new turbo, said his intake manifold needed torn apart to clean it out (which is possible, but unlikely). The costs of labor he was quoted was around $4k. I mentioned to him to replace the turbo speed sensor. He did, called me back and said no more problems. Cost him about $120 for the sensor and about $80 for labor. Much better than $4k. Hope this helps someone else as this is a common problem on the CM2250s over 500k mileage.