Have an 05 that I did the SEGR install on 2+ years ago so EGR is out of the picture totally.Throttle valve control is also working properly.No issues until today,Parked the jeep last night and started up this morning to these codes.Ran fine Yesterday with no issues,Now no power and light smoke under heavy pedal.No hose fractures. Ran good for a few minutes then returned to low power,idles fine. MAF sensor is clean,no oil or residue on it.
Is this an item covered under the original 7/70,000 warrenty?
Can anybody help Me?
rubicon03

Do you mean MAF or MAP/boost pressure sensor? I don't see how the MAF on my '05 could possibly get sooty or oily.

My P0299 was definitely related to the EGR. The Eco tune retired it permanently.

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'05 Sport CRD 107k miles. NOBODY knows everything.

P1250 is a fault on the wiring for the vacuum modulator that seals off the reservoir for the VGT controller, and/or the modulator itself.

The VGT controller is the modulator with the filter on the bottom of it - the modulator related to the P1250 is the other one.

The P0299 is underbooost. I would guess that your modulator (for the reservoir) is bad, since without vacuum available to the VGT controller the vanes default to the fully open position and you won't build much boost.

I would recommend to bypass the vacuum hoses around the reservoir modulator to see if the vehicle performance comes back to normal and the P0299 disappears. If so, you need a new modulator.

MrMopar64,
I connected the hoses together for the reservoir modulator as you suggested and all the power came back and no more P0299 code.I will be purchasing a replacement control tomorrow to see if it completes the repair and eliminates the 1250 code. Not an expensive part ,around $30.
What exactly is the purpose of this modulator in the circuit? A safety of some sort???

Thanks for your input,I will follow up when I'm done.
rubicon03

I have never seen any residues on the MAF on this 05 either,but I have seen other posts in the past where members have talked about oil on the MAF sensor.The MAP sensor stays clean on mine because I installed a PRO VENT 4 years ago and it does an excellent job seperating the oil mist from the crankcase gases,and the EGR was totally disabled 2+ years ago.NO oil NO soot.
Thanks for replying
rubicon03

The purpose of the modulator (broken on your KJ) is to seal off the vacuum supply to the VGT controller when the ECU is turned off. This is because it takes the engine a certain amount of time to evacuate the vacuum system and have a certain level of supply, and during this time of evacuation you have poor or no vacuum available to control the VGT. By having the modulator there, it allows for immediate possibility for the VGT control.