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Waterloo

Sounds like an electrical issue. What brand and model truck do you have?

zyNoT

2012 Peterbilt 386

Rawze

(07-21-2017 )zyNoT Wrote: 2012 Peterbilt 386

Maybe this helps...
http://rawze.com/forums/showthread.php?t...05#pid3505

zyNoT

(07-21-2017 )Rawze Wrote:
(07-21-2017 )zyNoT Wrote: 2012 Peterbilt 386

Maybe this helps...
http://rawze.com/forums/showthread.php?t...05#pid3505

I've actually taken a look at that post, but the ECM isn't losing voltage to itself.
It's almost like the ECM says "okay, you're way off here so I'm ignoring you" to the intake manifold pressure sensor, because it also monitors temperature and that parameter still shows a consistent value. So my guess is the sensor has consistent power, however the turbo speed sensor shows voltage but the speed drops to 0 every few seconds at idle which is strange in my mind unless someone here would say I'm barking up the wrong tree.

Waterloo

This may sound silly, but have you pulled your fuses, thinking the inline to the ECM, and replace with a new one? And I would go as far to replace all of the mini fuses in your fuse block and see if that helps. If you have breakers, replace them with mini fuses in areas that you may think could cause intermittent issues. Another thing, these systems, I forget the term...

My jake and ABS idiot lights would light up going down the road, and it was driving me nuts. I took the truck to the dealer and the only thing that popped up on their computer was the compass module. I bought one for $20 on eBay and it solved my electrical issue. My Jake and ABS system was routed through this stupid compass module. Maybe you have something like this going on. Just a thought.

Rig Wrench

(07-21-2017 )zyNoT Wrote:
(07-20-2017 )Rig Wrench Wrote: I had this problem on my 871, every couple months it would act up. The plug just simply wouldn't hold tight on the sensor. Got a new set of pins and new plastic plug. Problem solved

I would hope my issues would be this easy, but once the connector is on it's extremely hard to get off so I'd say it's making a tight connection.

Just cause the plastic plug is tight does not mean the pins inside it have a good contact.

zyNoT

UPDATE: It appears to be the wiring to the turbo speed sensor. Sensor itself looks good, wiring has a problem. Using graph included in pictures, I was able to diagnose by having someone else move the wires around, turbo speed would stay at 0 when wire was held in a certain spot and manifold pressure would be ignored by the ECM less than a minute later.

zyNoT

Also for those who have this problem later, once the ECM has ignored input from the manifold pressure sensor, it takes 5 key cycles before it will reset and try to read from it again or 3 hours ECM time.

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.