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Yukon "Reduced Engine Power message"

74 messages,  Last post on Oct 12, 2009 at 9:54 PM

You are in the GMC Yukon Forum. Your Hosts are steve_ & tidester

What is this discussion about? GMC Yukon Denali, GMC Yukon XL, Car Safety, Electrical, Engine, SUV

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#63 of 74 Re: 2003 Yukon XL - Reduced Engine Power/slow to kick over [skewter] by yukon03 Apr 14, 2009 (5:56 am)
Replying to: skewter (Apr 04, 2009 4:37 pm) Greetings! How did you check the alternator? Did you remove it from the vehicle or check it while it was running? I checked my battery with a voltage meter while it was off (12.3v) and when it was on (14.3). The battery is 29 months old and is a Duralast from Auto Zone! Still have the warranty receipt and was getting ready to head up there and get it replaced until I checked the voltages. Would the harness cause the false/positive voltage check! I am grasping for answers to get this fixed the first time as we are going camping next week and I use my Yuk to pull or pop up camper and I am a little stressed right now!! Any assistance will be greatly appreciated!
#64 of 74 Re: FOUND THE PROBLEM!!!!!!!!! [stephc1] by yukon03 Apr 14, 2009 (6:31 am)
Replying to: stephc1 (Sep 17, 2006 5:38 am) Can anyone tell me where the ground wires are on my 2003 Yukon!! I have read almost every post on this site regarding the Reduced Engine Power situation and I have come to the conclusion by troubleshooting my Yukon and just watching the alternator gauge meter fluctuate that this might fix my problem as well!! The battery and the alternator are fine on my vehicle. If someone could please send me a pic of the ground wire location and that computer/battery harness wire everyone is referring to I would greatly appreciate it!!! My Yuk has been sitting in the driveway for two weeks now because I am afraid to drive it in fear of getting stuck or involved in an accident!! Going camping next week with the pop camper and need to have this problem resolved by then!!Thanks for all of your support, this forum rocks!!!!!! Replies to this message: rsht (Apr 16, 2009 3:54 pm)
#65 of 74 Reduced Engine Power repair results? by yukon03 Apr 14, 2009 (6:38 am)
Are you having anymore issues with the Reduced Engine Power problem after you changed the battery?
#66 of 74 Re: FOUND THE PROBLEM!!!!!!!!! [yukon03] by rsht Apr 16, 2009 (3:54 pm)
Replying to: yukon03 (Apr 14, 2009 6:31 am) See post #22 from bunchz71, and the provided picture from him/her may give you an idea of the wiring...
#67 of 74 Help! Reduced Engine Power Warning by wendygee Jul 07, 2009 (5:02 am)
Hello! I have a 2004 Chevy Avalanche and my Reduced Engine Power Warning flashed. Upon conducting a diagnostic check the following popped up: P0120 Throttle/Pedal Pos sensor A clef malf P0156 025 clef malf 2/2 P0157 025 clef low volts 2 2 P0332 knock sensor 2 clef low input bank 2 P0496 Evap high purge flow fault P2135 Throttle/pedal position sens/SW A/B voltage correlation I HATE the idea of going to a dealer to have the issue taken care of because I am hoping it's either faulty wiring or a sensor and in owning cars for over 20 years I have yet to have a good experience with taking my car/truck to a dealer to have it repaired. Does anyone have any suggestions, guidance, or direction? Even if I could get my hands on an Avalanche electrical schematic I may have a shot at troubleshooting this issue? the biggest problem is that the engine will not accelerate higher than 20 miles per hour once the warning comes on, and it comes on sporadically so it needs to be taken care of ASAP. Help anyone? Thank you!!! Replies to this message: rsht (Jul 12, 2009 7:07 am)
#68 of 74 Read Previous topics by bunchz71 Jul 07, 2009 (9:17 pm)
I would suggest to try and read some of the earlier post in this forum on this topic. Lots of good info. Thanks,
#69 of 74 Re: Help! Reduced Engine Power Warning [wendygee] by rsht Jul 12, 2009 (7:07 am)
Replying to: wendygee (Jul 07, 2009 5:02 am) Wendygee, I saw your post a few days ago and was not able to suggest anything until now... Basically, from your list of trouble codes and what I can find is to begin your trouble shooting from the Throttle Pedal position sensor for proper resistance reading and if its physically secured in place and etc. Sorry, I could not find the service manual for your particular model year, so, you may have to check that in your local library or GMC Service Department for the sensor spec and location for trouble shoot. Good Luck!   As far as the Knock Sensor and other codes may be triggered by the pedal sensor, so zoom in on the pedal sensor first.
#70 of 74 car lost all power by cway Aug 26, 2009 (4:02 pm)
I have a 2000 yukon xl. I was driving it today and put my foot on the gas to give it some power and it did nothing. All of sudden my oil guage dropped from 40 to 0 and the car just died. I tried to start it again and it started and then shut off. I just replaced the transmission,water pump. Does anyone have any ideas what could be wrong with it??????? some one told me the fuel pump,sensor and then the most expensive the computer...please help
#71 of 74 i THOUGHT i fixed this problem by bandit79mpr Oct 07, 2009 (5:26 pm)
i own a 2003 silverado 1500hd crew cab, 6.0 automatic. i fought the reduced engine powre thing for almost a year, kept throwing the code of bad tpp, replaced it to no avail, tuned it up to no avail, new wiring harness from tpp (on pedal) to tac module to no avail, new throttle body and wiring harness to no avail........at this point i had spent almost $2000.00 and it was still running like crap, took it to the dealer for reprogramming and another throttle body (free of charge after i blew up in the mechanics face) and it ran fine for 2 days and i took it back again in may 2009 and the mechanic was gone when i went to pick up the truck, i asked the guy at the counter what he did this time and he said that the head mechanic had done "something" with the tpp but he was'nt sure what. the truck ran like a top all summer with trips to the mountains towing my camper, runnung all over the place looking for parts for my restoration projects and daily trips to work. around the middle of september the temperature started dropping into 40's and 50's at night and guess what?, that good ol reduced engine power light came on again. the mechanic that worked on the truck and "fixed" it cannot be found because the dealership has since closed down. so , does temperature affect whatever is happening? (the same tpp code is being sent) can i only drive this truck inthe summertime? my truck has 76,000 miles on it now and it is useless to me if i cannot safely drive it. i have owned,driven, and worked on chevy cars and trucks for the last 20 years and this new generation of wireless throttles have convinced me to never own another one. i think i'm gonna go buy a toyota............................ p.s. i had a little luck with mine if the light would'nt go away after 4 or 5 starts by unhooking the positive battery terminal for 5 mins or so , this usually gives me 6 or 7 trouble free starts before i have to do it again. good luck and if anybody else has this problem and it seems temperature related like mine, please let me know how you finally fix it. Replies to this message: rsht (Oct 08, 2009 4:26 am) yukon03 (Oct 08, 2009 5:30 am) bunchz71 (Oct 12, 2009 9:54 pm)
#72 of 74 Re: i THOUGHT i fixed this problem [bandit79mpr] by rsht Oct 08, 2009 (4:26 am)
Replying to: bandit79mpr (Oct 07, 2009 5:26 pm) Just wondering if you know the Trouble Code(s)? I assume something in the range of: P0120, P0122, P0220, P0222, P2135....... Replies to this message: yukon03 (Oct 08, 2009 5:30 am)

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