"Power Reduced" light on 2008 Chevy 3500HD Dually

[Sidecountry]

We're pulling our Cyclone 4100 and after a few hours I get "Power being reduced". Tranny temp is 210 deg. I'm guessing its a sensor trying to protect the Tranny? Anyone know about this issue. Serious pain!

 

[danemayer]

Hi Sidecountry,

Welcome to the posting side of Heartland Owners Forum. You've probably figured out by now that there's lots of useful information here along with a great bunch of friendly and helpful people.

Some additional information might help people respond with more useful answers. What engine does your TV have? Do you know the rear axle ratio? Was this going up a steep grade?

 

[Lynn1130]

Is this a Duramax with Allison tranny?

Sounds like it went into "limp" mode but I am surprised it did that at 210 degrees. I think the normal warning temp is 250 and I have heard that you get two warnings one at 250 and one at 270. My transmission temp gauge does not show red marks until 280. I wonder if the gauge is not matching what the trucks computer is seeing. I see 200 to 210 with the trailer in tow going up grades but normal flat tow is around 200.

Are you in tow/haul when towing? If not you should be.

 

[Sandpirate69]

You need to check the ECM for codes. If your DIC is giving you that, then you should have a mechanic or someone with a code reader check it for you. According to my transmission guy, who builds trannys for those of us who can't leave things alone, 270 deg. it will go into Limp Mode to care for itself. I have yet to experience my dually in limp mode, but what exactly are you feeling when this info pops up? Does the truck stay locked in 2nd gear? Actually you answered my question, if this happens only when you tow you are not in limp mode. If you were you would have to clear the code in order to reset.

 

[Speedy]

Was you engine temp high as well? Were you climbing a steep grade and had the hammer down? You may have hit the thermal barrier and the engine starts shutting down to prevent melting pistons.

 

[Sumo]

I'm having what I believe is the same problem. Happened again last weekend, mine will sometimes "fix it's self" after about 1/4 of a mile or I need to re-starting the truck. My research indicates it maybe a "MAP" sensor problem. Going to replace that sometime next week.

 

[Bob&Patty]

Dont replace anything until you know what the code is. BTW, do you have an air filter that requires oiling? Like a K&N? If you use too much oil it will screw up the mass air flow sensor. Sometimes you can clean them.....sometimes they have to be replaced.

 

[Lynn1130]

You are correct on the MAF and oiled air filters but the MAP is something different. Manifold Absolute Pressure. K&N filters and the like are not recommended for the Duramax. They do foul the MAF which then makes the ECM try to compensate for incorrect airflow readings and some strange performance including the reading that he has. The MAF can be cleaned. There are conflicting thoughts on whether the MAP should be cleaned. Some do it with no issues.

Many auto parts stores have code readers. Once you have the code an Internet search for your specific engine will tell you what is happening.

 

[Bob&Patty]

Yes Lynn, you are correct. I understand what you are saying. I do however have an understanding of GM vehicles. I was a GM tech for 47 years. That is why I stated...find out what the code is and don't just start using the "shotgun" approach in the diagnoses. You may not have componet failure but a critter could have chewed a wire somewhere. If I knew what code was set ( current or history), I might be able to help.

 

[Lynn1130]

I agree.

 

[Bob&Patty]

Just an added note. I would never buy a remanufactured part from anyone. Go to a GM store and buy a new one. Most replacement parts have a lifetime warranty and the dealer has to replace it for free even if you install it. Dont get better than that folks. No Pep Boys specials for me. OH, BTW, how old is your TV... if it is an emissions item...it might still be in warranty.

 

[Sidecountry]

It's an Allison/Duramax 2008 3500 HD Dually, 156,000 miles. "limp mode is exactly what it feels like. It comes to a crawl. It's also giving a check engine light, "replace fuel filter" indicator but it was replaced last week, it also is now giving "oil pressure low, stop engine" but the pressure is fine on the in dash indicator. I'll go get the error codes...

 

[Rubbersidedown]

I had a 2008 Duramax/ Allison in a 2500HD. "Power Reduced" would come on with fuel filter problem. Really the only issue I ever had with that truck. I got to the point where I would just replace about twice as often as recommended to avoid the issue.

 

[danemayer]

I had a 2008 Duramax/ Allison in a 2500HD. "Power Reduced" would come on with fuel filter problem. Really the only issue I ever had with that truck. I got to the point where I would just replace about twice as often as recommended to avoid the issue.

Hi Rubbersidedown,

Welcome to the Heartland Owners Forum and thanks for contributing to the discussion.

 

[Westwind]

I have a 2008 D/A and went into limp mode and threw a check engine light while towing my travel trailer to Florida, it was about a year old and I reinstated Onstar and they told me that it was a Emission System problem, after spending and hour in the garage being checked out nothing was found and we shut of the check engine light and we were on our way. I've had the check engine light come on for a bad glow plug and it's on again but I haven't checked it out yet, I'm hoping another glow plug, they are cheap in comparison to other stuff. I'm past the 5 year mark so no warranty.