2003 GMC Yukon Denali XL: sudden loss of power

6 of the 32 complaints about the 2003 GMC Yukon Denali XL describe sudden loss of power.

owner complaints: 6
of this car's complaints: 19%
typical mileage: 175,981
recalls: 0

Is there a fix? 23 service bulletins cover this area of the car. See below

Sudden loss of power by model year

2016
1
2013
1
2010
1
2009
1
2008
2
2007
2
2006
1
2005
1
2004
3
2003
6

What owners say

Filed Feb 5, 2015 · Driver assistance, Electrical · 200,000 miles · WI

Vehicle went into reduced engine power and stabiltrak warning light came on. Reduced speed from 60 to 10mph. Now occurs on a regular basis.

Filed Nov 23, 2014 · Acceleration, Engine · 145,000 miles · WI · crash

Vehicle powers down without any pattern, rhyme or reason. It will do it at 5 MPH, and at 55 MPH, when driven a lot, and when not. Reduced engine power light turns on, vehicle suddenly slows to 25 MPH max, steering becomes hard, brakes too. Then will totally shut off immediately. I have replaced the battery, throttle body assembly and wiring harness twice. Fuses, fuel pump and filters, oil, and everything else as recommended. It put me in the ditch. It stranded me in the center of a freeway in winter. When it sits for a while, it resets, only to do it again. T/c light turns on also. I found out that I can manually reset the reduced engine power for a few moments (to get out of the center of the road) by turning the ignition switch on and off very fast. It is a extreme safety hazard! I haven't driven it in months due to absolute fear for my life. When its in reduced engine power mode, I can't get it to go above 25, and going up hills can't go above 5mph. If I am pulling a trailer, it starts to go backwards. This thing is going to kill someone! Please help

Filed Jan 7, 2014 · Driver assistance, Engine · 195,000 miles · CO

Intermittently at hwy and side road speeds, truck will shut down, check engine light comes on and extremely rough idle and loss of engine power occurs. Have followed all recommended fixes but problem persists. Engine code 1516, throttle position sensor out f range +- .05 volts. Scary problem, as this occurs without warning and causes immediate loss of speed. Many many complaints posted on the internet of this same problem but no gmc recommended fixes or assistance. Refuse to take this to a dealer and let them poke around at $95 / hour and or to throw parts at truck in hopes of correcting. Gmc needs to address this potentially fatal problem.

Filed Oct 25, 2011 · Acceleration, Engine · 175,981 miles · OH

I was driving my yukon 2003 denali and the error message showed up "reduced engine power". I wasn't able to get the speed up to 30 MPH on the highway. I pulled into a parking lot and had someone come pick me up. When I went to pick up my vehicle, the message no longer appeared and it functioned at normal speeds. I am nervous about traveling with my family in the vehicle now.

Filed Jan 25, 2011 · Engine · 160,000 miles · MS

2003 yukon denali. Reduced engine power while driving down the interstate, highway and or street. No matter what the speed without warning the power shuts down and you have no choice but to try to get the side and turn off the key and let it sit. Then try again. I have had it in the shop six times over the past three months still not repaired and ongoing hazard to me and whoever is in the vehicle with me or behind me. Help please!

Filed Jan 9, 2011 · Electrical · 70,787 miles · IL

"reduced engine power/stalility control disengaged" message displayed, engine went to idle and would not exceed 5-10 MPH. Traffic from behind served to avoid decelerating vehicle. I understand this is something that is somewhat common with these gm models. The possibility of rear end collisions may be experienced due to rapid deceleration due to loss of power. Happened intermittently again during the day. It clears itself after the vehicle sits for a while but there is no warning when it might happen again. Information received form various forums state it is believed to be within the wiring harness for the throttle position sensor.