OK.....who has had this message displayed on their DIC and any ideas that would cause this message, as you can see no check engine light:confused: the message will come on for a few minutes will driving and idleing and then power is restored:confused::confused:this has happened 4x today ....disregard the brake & abs light thats another matter

Last all things that will trigger the ECM to display that message

Thanks Dave

http://www.dieselplace.com/forum/garageimage.php?do=full&p=117732&d=1285813395

Welcome to the club!

http://www.dieselplace.com/forum/garageimage.php?do=full&p=113881&d=1277608029

Do some searching guys... looks like there are several reported problems like this... but for the most part they happen in the winter. Among the top issues:

Snow intrusion into the filter box (causing reduced airflow)
MAF sensor fouled/FUBAR'ed
MAP sensor problem
EGR problem


First and foremost - scan for any codes. After that, do some research. I found a lot of threads reporting the problem... with several different issues.

BTW, from what I've read, you should be able cycle the keys several times and get it to restore normal function... again based on 5 minutes worth of reading.

Good luck!

Had this happen to my truck when couple months old. Was throttle position cable to sensor chaffed. Dealer replaced and re routed cable - good since. I believe dealer said there is a tsb on it.

Do some searching guys... looks like there are several reported problems like this... but for the most part they happen in the winter. Among the top issues:

Snow intrusion into the filter box (causing reduced airflow)
MAF sensor fouled/FUBAR'ed
MAP sensor problem
EGR problem


First and foremost - scan for any codes. After that, do some research. I found a lot of threads reporting the problem... with several different issues.

BTW, from what I've read, you should be able cycle the keys several times and get it to restore normal function... again based on 5 minutes worth of reading.

Good luck!

X2 same happened to me (no winter cover) limped with no CEL

I had removed my air box when I installed my EGR Blocker plate and received that message when I forgot to hook the wiring harness back up to the air box before I started the truck. I believe it was related to the MAP sensor. Once I hooked the harness back up, everything worked fine. This might not be your issue, but one thing that causes reduced power.

I get this in the winter, when the corn niblets and soybeans in my Illinois fuel congeal in my fuel filter.

Seen snowpack in airfilters when they have airbox mod. and powder snow blows into that intake on the fender without those fins. It will happen in bad storms or busting big drifts. What a pain when it craps out.

One of my customers had this issue with a 2010 LMM when he installed a drop in replacement airfilter. He did not modify the air box at all, just a filter. It was a MAF concern as someone else had suggested. Im guessing if the airbox were modified with an OEM filter, similar issues may exist? I contacted the manufacturer about the issue and they stated the filters have been changed just for the 2010 Dmaxes and their altered software parameters as compared to the 2007.5-2009's. This change was noted by the color difference on the filter seal. They suggested "take the filter out and see if it goes away". Thanks guys!:rolleyes:. Ultimately, the truck is back to the OEM filter and has no concerns any further. I know this doesn't solve your problem, but hope it helps direct you to an area of concern.;)

My Hitachi MAF sensor is fubar. Dammit!! How much do these cost? I could claim it under powertrain warranty but I'll have to cover up some of my engine with blankets and put a piece of sheet metal covering my diagnostic port :-) My FRIENDLY GMC dealer shut down :(

are you sure that it's the MAF? if you have and kind of filter other than a GM I would replace that before a MAF. Even a wix can set a code

Ive got more under the hood to void any warranty. I cleaned the maf with CRC MAF sensor cleaner a few times. Still. Code comes up upon start. I've been running with no air filter all day to see and its not reading proper amount of air.

you're running with NO air filter? Hmm? anyways that would make sense too. If there is too much air flow it will limp on you. I'm not saying that you MAF is f'd up just a thought.

you're running with NO air filter? Hmm? anyways that would make sense too. If there is too much air flow it will limp on you. I'm not saying that you MAF is f'd up just a thought.

I sprayed the hell out of my MAF sensor with crc MAF cleaner 4 days ago.....no message sence;)

Yes. I ran the truck with no air filter. I put a new filter on too. As I said I replaced the maf sensor and all is well now.

Yes. I ran the truck with no air filter. I put a new filter on too. As I said I replaced the maf sensor and all is well now.

Gee I wonder at who's cost though...:rolleyes::p:

I bought a cheap ~$40-$50 code reader at Walmart specifically for when this happens. I've only had reduced power from a clogged fuel filter (and the low rail pressure code). When it's happened, having that little reader with you is great. Reset the code, get home, look up the code and fix the problem.

I bought a cheap ~$40-$50 code reader at Walmart specifically for when this happens. I've only had reduced power from a clogged fuel filter (and the low rail pressure code). When it's happened, having that little reader with you is great. Reset the code, get home, look up the code and fix the problem.

I keep my EFI FlashScan V2 and an HP Mini 110 (AT&T broadband) netbook in the truck at all times. My tech 2 is also in the back as well.

So today my MAP sensor died. Time to get one of those now.

So has anyone found a list of every failure/problem that would trip the reduced engine power message?

Had the same problem when mine was two months old. It was a loose screw in the air filter box.

I'm having the same issue but worse. Mine goes into "reduced power" about every 3 miles while driving on the interstate at a steady speed. It started after a weekend of running it hard. Same results on all 5 EFI programs. Keeps setting an EGR code which has been deleted. Will reset when I slow down to an idle or clear with EFI V2. If anybody can help I would appreciate it!

I got the Engine Power is Reduced message the other day and ran in limp mode. After I got where I was going (about 15 miles) when I came out, the message was gone but I wasn't in limp mode any more but the check engine light was on.

I made a dealer appointment but today, I noticed the check engine light was off and all seems well. I guess I'll keep the appointment but am wondering if the problem fixed itself or what. About 25K miles on the truck. Recent (5K) fuel filter change.

Have read posts but What are the MAF sensor and the MAP sensor. Any suggestions for what to do until next week 'til I get to the dealer?

Thanks.

Put contact cleaner on the MAF when you change oil it's a good habit since you usually look at that air filter anyway too. Pump the filter head primer for a quick pressure holding check around the WIF those crack if tightened to much or have 300 lbs. of torque the plastic doesn't hold up good. The O ring on the fuel filter can give you problems too in this Problem Chase seen those kinked or out of the groove causing a leak from loss of seal too. Some quick things to check and watch seen it had it good luck....

happened to me today twice, once at a red light and then exiting on the off ramp. gunna do some more digging

Got the "REDUCED ENGINE POWER" message about a year ago, was only 10 miles from dealer, limped it there, they had me back on the road in less than an hour. Mine was the MAF sensor, the service manager said he had seen the same problem before. Havent had the problem since.

Two weeks ago I was driving in a snow storm and the "Reduced Engine Power" message showed up. I limped it to the local Chevy dealer and my air filter was clogged with snow. They also found out that my EGR valve was bad at 33,000 miles. After they installed the new air filter and installed my winter front it has been good to go. What kind of 4x4 truck can't drive in snow? I had a 2007.5 LMM that never had an issue with snow, but my 2009 LMM has had an issue twice now.....WTF?:confused:

today is the first time my truck has seen snow, had the reduced engine power message come on, checked this site and come to find out my filter and box were full of snow, glad i checked the site but sucks that these pickups cant handle snow, chevy better figure something out and the 2011s aint any different,

same thing here... snow around the air filter = power reduced... WTF !!!

Question. if it is caused by the snow, do I have to clean the air filter it or it will go away when warmer ?

Mine did it once when I had bad fuel & when I was towing in tow haul mode, in the summer time. If its doing it in the winter hit up your dealer for the winter air intake lid with 5 holes drilled in it & front grill cover.

I've had reduced engine power ever since I traded my '07 LBZ in for this dam LMM. I pull cows, and the LMM won't compare to the LBZ. Plus, snow does make the reduced power light come on. Because I pull several times a week, I don't like to put the apron on my '09. The apron goes on way too hard. To make a long story short, I am getting sick of the new diesels, and am ready to sell my '09 with 20,000 miles and look for a good '07 again.

OK.....who has had this message displayed on their DIC and any ideas that would cause this message, as you can see no check engine light:confused: the message will come on for a few minutes will driving and idleing and then power is restored:confused::confused:this has happened 4x today ....disregard the brake & abs light thats another matter

Last all things that will trigger the ECM to display that message

Thanks Dave

http://www.dieselplace.com/forum/garageimage.php?do=full&p=117732&d=1285813395
That message came across my screen a month ago and was running a little slugish. I put a NAPA gold fuel filter on it and havn't had a problem since.

I during my summer run with the trailer my air filter got clogged with sand (High winds that day) & the msg & engine light came on. The msg cleared after I killed the truck for about 1hr. The next day the check engine light came on no msg. Had it looked @ 2Xs & all they said was it could of been from DPF didnt regen & OR MAF Sensor & or EGR. Dont go to Desert Buick & GMC in Henderson NV. Clueless on Diesels.