My 2004.5 CTD 2500 QC 4X4 is showing the code P0299 (turbo underboost). Any ideas what might cause this. My dealership can't get it in until late next week. It seems to be running ok, but I am only getting about 14 mpg (don't know if there is a connection). I have only had it for a month or so. It has 75K, so it should still be under warranty. Any help would be greatly appreciated.

 

do you have a downloader on it or a performance box??? if so you may need to check out some of the connections and make sure they are tight.

if everything is running right though, run by your local parts store that has an OBD II reader and get them to delete the code. if it doesnt come back your ok. also the code will go away after 5 full starts if the condition no longer exists.

 

No. I don't have any upgrades, the truck is completely stock. Does the truck have an accessible boost sensor? I was wondering if a bad sensor could be the problem. Thanks for the input Drew.

 

Also,could there be a boost leak? I just got back from town and now the truck has gone into limp mode. If there is a leak, is there a good way to find them? I gave the dodge service guy some of my information and he said that the truck had a new turbo installed at 55K miles. I wish I would have known before I bought it! Any insight would be appreciated.

 

a boost leak wont cause a 0299 code, I know first hand after neglecting to tighten one of my clamps[:@]

anyway, the MAP sensor your wondering about is easily acessable. on the drivers side of the engine, it is right under the engine data plate. now dont get it confused with the rail pressure sensor. the MAP sensor is closest to the engine.

one thing I would ask the service tech would be why did the tubo have to be replaced. . .that might lead you into a direction that can get this fixed.

you might also want to make sure the waste gate is plugged in properly as well as any other sensors on the turbo.

 

Thanks for the input. I unplugged and replugged all of the sensors. I couldn't find any that seemed loose, but I had the code cleared and I drove the truck about 55 miles today with no issues. Hopefully it was just a one time thing.I'll let you know if the problems returns. Thanks for the help.

 

I've driven the truck for a few days now and it seems that it doesn't have as much power as it should. The check engine light is gone, but the code 0299 still appears when I cycle the ignition. I talked to a friend of mine who said that it could be the MAP sensor. He thought that was a common problem. I know the sensor is easy to replace, but are they expensive? Is it worth a try?Do I have to get one from Dodge or are they available at any autoparts store?

I installed a Diablo Sport Power Puck after I cleared the light a few days ago. I drove with it on the 60 hp setting for a while, but I was afraid that the engine wasn't running right so I turned it back to stock. Seemed to do okay with the power puck, but still didn't have the power it should and I got quite a bit of black smoke. Any thoughts would be helpful. Thanks.