2003 GMC Yukon Xl 1500

VEHICLE RANDOMLY GOES INTO REDUCE ENGINE POWER MODE AND STALLS WHILE DRIVING. THIS HAS HAPPENED MULTIPLE TIMES WHILE DRIVING ON A HIGHWAY AND GOING UP A HILL WHERE IT NEARLY CAUSED A THREE CATASTROPHIC ACCIDENTS. BASIC RESEARCH SHOWS THAT GM HAS KNOWN ABOUT THIS ISSUE SINCE THE VEHICLES WERE A FEW YEARS OLD AND IT AFFECTS MANY YEARS OF GM VEHICLES. THERE IS A PROBLEM WITH BAD GROUNDING CONNECTORS RELATED TO THE THROTTLE BODY SENSOR AND AND WIRING HARNESS.

TL* THE CONTACT OWNS A 2003 GMC YUKON XL 1500. THE CONTACT MENTIONED THAT THE PREVIOUS OWNER OF THE VEHICLE EXPERIENCED A FAILURE WITH THE REDUCED ENGINE POWER WARNING INDICATOR. THE DEALER REPLACED THE THROTTLE BODY, BUT THE FAILURE CONTINUED BEFORE THE CONTACT OWNED THE VEHICLE. THE CONTACT EXPERIENCED THE WARNING LIGHT RANDOMLY FLASHING, WHICH DRASTICALLY REDUCED THE SPEED TO LESS THAN 20 MPH. THE CONTACT HAD TO CONSTANTLY TURN OFF AND RESTART THE VEHICLE, BUT THE FAILURE CONTINUED TO PROGRESS RANDOMLY. THE DEALER REPLACED THE WIRING, 02 SENSOR, THE THROTTLE BODY WAS REPLACED A SECOND TIME, THE BATTERY, AND THE ALTERNATOR. THE REPAIRS FAILED TO PROVIDE A PERMANENT SOLUTION AND THE WARNING LIGHT CONTINUED TO ILLUMINATE FOR THE REDUCED ENGINE POWER. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED. THE APPROXIMATE FAILURE MILEAGE WAS 188,000.

WHILE TRAVELING TO WORK MY VEHICLES CHECK ENGINE LIGHT CAME ON AND THE REDUCED POWER WARNING CAME ON AT WHICH TIME I HAD COMPLETE LOSS OF ACCELERATION, COMPLETE LOSS OF BRAKING, AND COMPLETE LOSS OF STEERING POWER. I THEN HAD TO COAST TO A STOP AND ATTEMPTED TO RESTART THE VEHICLE 6 TIMES BEFORE I WAS ABLE TO GET THE REDUCED POWER WARNING TO GO OFF AND WAS ABLE TO DRIVE ALTHOUGH THE CHECK ENGINE LIGHT STAYED ON. THIS IS THE 2ND TIME THIS HAS HAPPENED TO ME IN 2 DAYS WITH THE LOSS OF POWER. I HAVE HAD THE REDUCED POWER WARNING ON NUMEROUS OCCASIONS YEARS PAST BUT NEVER HAVE I LOST TOTAL / ABSOLUTE POWER TO CONTROL THE VEHICLE, THIS IS A TOTAL DEATH TRAP FOR ANYONE WHO HAS HAD THIS EXPERIENCE, ESPECIALLY ON THE FREEWAY OR HIGHWAYS AT HIGH SPEEDS. I HAVE READ NUMEROUS ACCOUNTS OF THIS SAME ISSUE AFFECTING OTHER GMC OWNERS AND HAVE SEEN NO RESOLUTIONS OR ANY RECALLS FROM GMC. I HAVE ALREADY REPLACED THE THROTTLE HOUSING AND HARNESS COMPONENTS, ACCELERATION PEDAL SENSOR AND YET THE ISSUE CONTINUES, SOMEONE IS GOING TO ( DIE ) BECAUSE OF GMC'S LACK OF CONCERN AND RESPONSIBILITY TO OWNERS OF THEIR PRODUCTS. I WILL NEVER EVER OWN ANOTHER GMC ASSOCIATED PRODUCT.

THERE IS AN ERROR MESSAGE THAT DISPLAYS ON THE DASH FOR MYSELF AND THOUSANDS OF OTHERS WHO OWN GMC/CHEVY TRUCKS WITH THESE MOTORS. THEY HAVE A DEFECTIVE THROTTLE POSITION SENSOR WITH THE TRUCK WHERE IT SAYS "REDUCED ENGINE POWER". I'VE FOUND 2 TECHNICAL SERVICE BULLETINS THAT SOMEWHAT ADDRESS THE ISSUE, BUT MANY PEOPLE TAKE THEIR TRUCKS TO MECHANICS AND DEALERSHIPS TO GET THE ISSUE FIXED AND SPEND THOUSANDS OF DOLLARS IN REPAIRS AND TROUBLESHOOTING TO GET THE ISSUE RESOLVED, TO NO AVAIL. THE 2 TECHNICAL SERVICE BULLETINS THAT I FOUND WERE #PIP3089B (DATED 10/31/2006) AND #PIP3042A (DATED 8/30/2004). I'VE SEEN ON MANY MANY FORUM POSTS ABOUT THIS ISSUE AND POSSIBLE FIXES, WHICH WHEN I READ DEEPER INTO THEM, SEEM TO NOT BE TRUE FIXES.

I KEEP HAVING THE DISPLAY SAY "REDUCED ENGINE POWER". I'LL BE DRIVING ON THE HIGHWAY, DOING 65 IN RUSH HOUR TRAFFIC, WHEN ALL OF THE SUDDEN THE ACCELERATOR NO LONGER ACCELERATES AND IT DISPLAYS "REDUCED ENGINE POWER" ON THE GAUGE CLUSTER DISPLAY. FROM WHAT I'VE SEEN ONLINE IT APPEARS TO BE AN ISSUE WITH THE THROTTLE POSITION SENSOR ON THOUSANDS OF OTHER SIMILAR VEHICLES WITH THE SAME ENGINE, CHEVY SUBURBAN'S, SILVERADO'S, TAHOE'S, ETC. I REPLACED THE THROTTLE POSITION SENSOR AND THE HARNESS (BECAUSE I HEARD THE HARNESS MIGHT ALSO BE AN ISSUE) AND I AM STILL HAVING THE SAME PROBLEM WITH MY TRUCK. IT HAS DONE IT OVER A DOZEN TIMES ON ONE TRIP BACK FROM WORK (80 MILES FOR ME). I HAVE TO PULL OVER TO THE SIDE OF THE ROAD (IF POSSIBLE) AND TURN OFF THE TRUCK, THEN WAIT A SHORT PERIOD OF TIME, THEN TURN THE TRUCK BACK ON. THIS USUALLY FIXES THE ISSUE, BUT IT DID NOT HELP ME WHEN IT HAPPENED TO ME IN THE TUNNEL AND I WAS GOING 5 MPH (TOP SPEED DURING THE "REDUCED ENGINE POWER" MODE, ONCE YOUR DRIFTING STOPS (BECAUSE YOU DRIFT, IT DOESN'T ENGAGE THE BRAKES). I WAS EXTREMELY WORRIED THAT I WOULDN'T MAKE IT OUT OF THE TUNNEL WITHOUT GET REAR ENDED, AND ONCE I MADE IT OUT, I WAS JUST OUTSIDE OF THE TUNNEL AWAITING ROADSIDE ASSISTANCE, IT WAS VERY FRIGHTENING, WITH MY DAUGHTER IN THE CAR.

VEHICLE HAS BEEN SERVICED SEVERAL TIMES SINCE FIRST OCCURRENCE IN SEPTEMBER 2014. "REDUCED ENGINE POWER" AND SERVICE ENGINE SOON SIGNALS APPEAR ON VEHICLE PANEL CAUSING ENGINE POWER TO BE REDUCED IN A MATTER OF SECONDS. HAS HAPPENED TO ME GOING 10MPH, 55MPH, AND 70MPH ON HIGHWAY, CAUSING A NEAR REAR COLLISION BECAUSE I LOST POWER SO QUICKLY. I HAVE HAD IT SERVICED 6 OR 7 TIMES SINCE SEPTEMBER 2014 AND THIS ISSUE IS NOT GETTING RESOLVED. THROTTLE BODY SENSOR REPLACED TWICE, THROTTLE BODY HARNESS REPLACED, ALL WIRES, AND SENSORS HAVE BEEN CLEANED AND THOROUGHLY INSPECTED. REDUCED ENGINE POWER OCCURS WEEKLY EVEN AFTER BEING SERVICED. *TR