# Reduced Engine Power



## vincent (Sep 15, 2008)

I've emailed B&B, but I want to get the hive's opinion if this has happened to you. Have a 08 2500HD with a 6.0. Today a message "reduced engine power" came on along with the idiot light on the tach.

If you had this problem, what did you do to solve it?


----------



## Sydenstricker Landscaping (Dec 17, 2006)

Never had this issue, but since it is an 08, take it right in to the dealer. The warranty should cover what ever issue it may be. Over heating could cause it or anything the computer may find a problem with on the engine. Are all your fluids up to the proper level?


----------



## pensty (Mar 29, 2009)

Had the same thing come up with my 08 (duramax engine though) and couldn't get more than 1500 or so rpm out of it. 
Dealer figured it was the throttle position sensors at the foot pedal. Ordered all three in, replaced them and still had the same prob! After some hunting around, the tech found some electrical tape wrapped around the sensor wires a foot or so away. This 'repair' he found wasn't quite good enough and there was enough of a short to mess things up. After repairing the repair, everything was cool once again.
Interesting thing though.....the service manager had asked if there was anyone messing around under there installing an autostart or brake controller, but both those things were installed options, and my plow wiring had not yet been done at that point. He wrote up the repair as 'chafed wires' and it was covered under warranty. 

Get her fixed up for the next snow!


----------



## vincent (Sep 15, 2008)

Update on this problem.

Took to chevy dealer today, they replaced the accelerator pedal assembly for intermittent operation per PIP3783B, whatever that means.

They wouldn't give the codes.

Hope this was the problem.


----------



## '08FX4SnoPro3K (Dec 22, 2009)

The new trucks with the DPF on the exhaust system are finicky. If your DPF gets clogged and your not driving fast enough for the cleaning cycle to take place the filter will become clogged to the point that the truck goes into reduced power mode to protect the engine. I doubt your problem is fixed yet. How is it acting. All of our fleet truck where I work now have these dame DPF's and when the truck locks into reduced power mode it needs to be connected to a computer to "force" a cleaning cycle then once the sensors on the DPF are getting the correct reading your truck will return to normal operation. 

Be careful until you know what that dealer did to your truck. When the DPF is clogged that bad it is basically an obstruction in your exhaust system. Check into it

my f350 has a visual indicator to tell me it is cleaning the exhaust filter and generally you need to drive it at above 30 mph for 20 minutes or more for it to complete the cleaning cycle. When your out plowing that is difficult to accomplish. Minecam on durring sunday's storm and I had to go up the highway fo a little while to get the cycle to finish. It wouldn't finish while I was plowing, or driving inbetween driveways


----------



## B&B (Nov 4, 2006)

[QUOTE='08FX4SnoPro3K;920372]
Be careful until you know what that dealer did to your truck. When the DPF is clogged that bad it is basically an obstruction in your exhaust system. Check into it

[/QUOTE]DPF wouldn't apply to Vincents 6.0 gasser.


----------



## '08FX4SnoPro3K (Dec 22, 2009)

<----DUHHH Ooops. Didn't see that anywhere. I just saw 6.0 and since I always have powerstroke on the brain I went with it. Sry.


----------



## Longae29 (Feb 15, 2008)

Anybody else run into this? If so what was the solution?

Went out tonight to check some properties and about 45 minutes into my run the check engine light came on and the message center read "engine power reduced" I pulled over shut the truck off checked the oil, started it back up check engine light was still on but no message.

Background: truck is an 09 with 18k on it truck is stock with plow and salter......it is damp here....this was the first time the truck has been driven longer than 15 minutes since probably august.


----------



## theholycow (Nov 29, 2002)

^It's just as the others in this thread report...


pensty;917190 said:


> Dealer figured it was the throttle position sensors at the foot pedal.


...I know this is old but technically that's the accelerator pedal position sensor, not the throttle position sensor (which is at the throttle, not the accelerator pedal). If you're watching live data from the OBD port you need to watch APPS not TPS. The APPS measures how much you're stepping on it; with DBW the TPS measures actual opening of the throttle to confirm that the actuator is obeying the computer.

Remember folks, with drive-by-wire you don't have a throttle pedal, you have an acceleration request input device that merely transmits your wishes to the computer.

Also, any time you get an error like that or Check Engine or Service Engine Soon your first order of business is to pull codes. Get the code numbers and search them at a GM forum, even if your scanner gives you text descriptions of the numbers.


----------



## dieselss (Jan 3, 2008)

what i have found out is 4 things...
1) the throttle plate needs cleaning......rare but maybe
2) throttle plate assm...was bad on one of our 6.0
3) throttle pedal...bad
4) wiring inbetween. 
exactly as cow says....your pushing on pedal,,,and that input is sent to the puter, which is them output to the throttle plate, which moves.
now us diesel guys have been dealing with this for years,,,now the whole industry has gone it flyby wire.......my h-d even has flyby wire


----------



## goel (Nov 23, 2010)

I had it happen on our 03. It sat for most if the summer, other than starting it up and letting it run occasionally. It probibally sat for 3 weeks just before this happened. 

Started it up and had the message.

Just left it running, and walked away. Took about 1.5 hours of idling but cleared it self and not a problem since. We just make sure to use it more and it's been problem free.


----------



## theholycow (Nov 29, 2002)

How timely that this was published today:
http://www.underhoodservice.com/Art...e_power_message_displayed_on_gm_vehicles.aspx
Apparently, besides the common accelerator pedal position sensor failure, it can also be caused by a redundant throttle position sensor mismatch. The article says that there are two TPSes and if there is a mismatch it will throw a P2135 and get Reduced Engine Power.


----------



## Longae29 (Feb 15, 2008)

Thanks for the feedback guys. Owners manual says its caused by engine getting hot, but I always keep an eye on the temp gauge and adjust the heat/plow accordingly this definitely is out of my league a trip to the dealer is clearly in order


----------



## NY_plow_guy (Dec 14, 2008)

I had this same issue with my 03. it would do it to me going down the road. normally i would have to pull over and shut it off and cycle the key several times and it would go away. after some research on the problem and checking the wiring to the throttle body. I had determined that the position sensor in the throttle body was bad. I got a used one from a used parts yard. replaced it one night after work in about 20 min and never had a problem again


----------



## Longae29 (Feb 15, 2008)

Update: Took the truck to the dealership, they said it was caused by the fact that we replaced OEM air filter with a NAPA filter. Check engine light is off, no error message now. Driving it back to the shop, I think I feel some hesitation around 2k RPM.....


----------



## dieselss (Jan 3, 2008)

WHAT?? Ok that's a new one on me


----------



## Longae29 (Feb 15, 2008)

yes, it seems to be contrary to everything i see above......we use NAPA filters in the other 8 diesel trucks we have....'09 is the newest, but the rest are 05-newer...


----------



## theholycow (Nov 29, 2002)

That makes absolutely zero sense. I'd love to hear a technical explanation.


----------



## TJS (Oct 22, 2003)

They just cleared the codes. That statement is bs.


----------



## Mr.Markus (Jan 7, 2010)

Longae29;1537106 said:


> yes, it seems to be contrary to everything i see above......we use NAPA filters in the other 8 diesel trucks we have....'09 is the newest, but the rest are 05-newer...


Hmmmm. My 07 does it when it's damp too....

Well not anymore.


----------

