P0234 Overboost DTC issue

[Heartbeat Hauler]

Was towing a U-Haul trailer (6x12) down the interstate through W.Va. at about 70mph. I started up a fairly long steep grade when the tranny kicked down, everything is going fine and then the truck feels like I let off on the accelerator pedal. After a few seconds the truck starts working just fine. This happened again a few minutes later.

I was watching the gauges real close so when the second event happened I got this information.

70 mph, Tow/Haul mode, cruise control, oil pressure 70lbs, boost never exceeded 22 lbs, EGT's 800*, RPMs 2500, SES light came on, Codes=P0101 MAF sensor perf.), P0234 (Over Boost).

I don't get it, I know there are guys running boost way over 22lbs, isn't this stock pressure? What gives? Any ideas? Check sig for mods.

[More Power]

Jeff,

I suspect the MAF code may be related to the overboost code. I'd work on the MAF code first, by cleaning the individual sensors within MAF sensor spray cleaner (available at NAPA). Let me know if you need more instructions. We have a story about this available in the subscriber area.

Jim

[Kennedy]

This is most commonly related to the 2001 ECM programming. It is often referred to as phantom limp mode. The issue is that the operating parameters are fairly tight and some trucks pass outside this window. Some do it only long enough to see reduced power but no DTC and others operate out of range longe enough that they set codes. Some don't do it for years but as the vehicle ages things change. Also related is odd P0093 codes occurring in much the same manner.

I have yet to have one NOT be cured by an ECM program change.

[Heartbeat Hauler]

Jeff,

I suspect the MAF code may be related to the overboost code. I'd work on the MAF code first, by cleaning the individual sensors within MAF sensor spray cleaner (available at NAPA). Let me know if you need more instructions. We have a story about this available in the subscriber area.

Jim

I've replaced my MAF twice, on dealership recommendations, so I am familiar with remove and replace. So cleaning with the tuner degreaser type spray is fairly straight forward as far as the MAF is concerned. There are two areas (wires) in the MAF that need spraying, are there any other things that must be done?


This is most commonly related to the 2001 ECM programming. It is often referred to as phantom limp mode. The issue is that the operating parameters are fairly tight and some trucks pass outside this window. Some do it only long enough to see reduced power but no DTC and others operate out of range longe enough that they set codes. Some don't do it for years but as the vehicle ages things change. Also related is odd P0093 codes occurring in much the same manner.

I have yet to have one NOT be cured by an ECM program change.

Can you speak more about this? I did have the latest flash upgrades from the dealer that was supposed to address some parameter issues with the baro/MAF sensor. Are you talking about a more extensive programming, i.e. EFILive type tune?

[Kennedy]

It's very rare to see a MAF sensor actually go bad. They may oil foul, but typically clean and re-install.

Actually a bit of a special tune based on the 2002 OS and your problems will go away. I hear a quite a few of these complaints with the 2001.

[Sportinh2o]

Im new here and own a '01 6.6 that is devolping a nasty habit of going into limp mode under load climbing a hill. Can you give the link to the story? Thx.


Jeff,

I suspect the MAF code may be related to the overboost code. I'd work on the MAF code first, by cleaning the individual sensors within MAF sensor spray cleaner (available at NAPA). Let me know if you need more instructions. We have a story about this available in the subscriber area.

Jim