2003 Chevrolet Silverado - Reduced En...

Long Beach, CA

#43 Sep 21, 2009

Jefferson, GA

#44 Sep 26, 2009
I have a 2003 silverado hd and the reduced engine power light came on about a month ago,my mech. scanned it and it was showing that the trottle position sensor was bad. About a week went by and the message came back.this time he replaced the throttle body. A week later the message came back agian,mechanic checked it agian and said it was showing low voltage, alternator is fine but I replaced the battery as the mechanic suggested.
Did fine for a couple days but now the freakin message is back.Anyone have any ideas on this one besides trying a new mechanic?I feel like the 900.00 bucks that I have spent has been a waste
All World Auto

New Market, MN

#45 Sep 29, 2009
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Mclean, VA

#46 Sep 29, 2009
Chris, try Sergio's suggestion and inspect the wiring near the throttle body. After spending $987 for a new throttle body and "new wiring harness", the problem reappeared after about two weeks. This time the dealer wanted $517 to replace another wiring harness. My son said, "You can do it, Dad!", so I had the dealer's tech show me what wires to replace (all 8, it turned out) and I did it. The wires that are there are gauge 18 or 20 and they tend to vibrate to pieces. I replaced them with gauge 14 wire and haven't had a repeat of the "limp mode" problem. It has been only a month, so I don't really know if this is the end of the problem or not. I think that maybe I didn't need to replace the throttle body, but we'll never know for sure -- I should have had them save the parts.

Jefferson, GA

#47 Sep 29, 2009
Thanks Ken. I plan on checking the wires in that area this weekend. I thought back and it seems after the components that I mentioned were replaced that the condition is occuring while driving in the rain or wet conditions,possibly causing a short some place. After the last episode,it has done well (kow) but I know the problem hasnt disappeared and I will check the wiring around the tb .Thanks Agian
Degreasing triggered it

West Jordan, UT

#48 Oct 3, 2009
Today, I decided to degrease my engine, let the stuff sit all day and then hosed it off. On the way to get a replacement air filter, BAM! reduced engine power, I almost got t-boned making the left hand turn onto the highway. I played around with the obd scanner at autozone, Seems the problem is where the cable plugs into the TPS sensor (left side of the engine cover. After I get home from the library tomorrow I'm going to have a look, I think the plug itself shorted or something. Next time I won't clean my truck if I don't have a job or any money to fix it, I just took out a loan to replace the darn wheel bearings, I wonder if I can get a real throttle like my 69 c10 has, All these computer components are a waste of time.

Braselton, GA

#49 Oct 7, 2009
After having a Throttle Position Sensor replaced,a Trottlebody replaced and a new battery installed on my 03 2500 silverado, the reduced engine power syndrome continued-but only when it was raining.After putting some thought into it,the past times when this happened, it was in wet conditions.Truck runs great when its dry outside,as it has been here for 2 weeks.
But last night the rain returned and alot of it.Left to go to work and made it less than a mile when boom, REDUCED ENGINE POWER. I pulled over, removed battery cable,relaced cable, started truck,REP was gone but the check engine light was on.Took it to the mechanic,he scanned it and it was showing 4 different codes(I didnt get these from him but they were all tps type codes).He told me that the GM tech notes on this situation pointed to mositure getting into the Throttle Control Module which is located under the windshield where the water all runs to.He removed the tcm (there was some mositure,but no corrision)wiped it off and sprayed it with dielectric spray, replaced and the check engine light was gone.That was it.
Doesnt it seem as if these engineers designing these autos that we all pay so much for would stop and think that sensitive electrical components would maybe be less problematic if they were actually located in the cab of the thing instead of under the hood where the water runs off the windshield?

Delhi, NY

#50 Oct 13, 2009
i have a 2003 2500 hd and i have had the reduced engine power light coming on for about a week. finally my truck just wouldnt start. i put a new battery new starter and checked every wire in the truck. i thought i had checked all the grounds good enough but the ground on the back of the block was rubbing and cracked the rubber sleeve and broke the wire so it was grounding out when it would it the block but when i hit a bump it would go out. its a purple with white stripe wire right behind the block on the upper side. i found it easiest to pull the plastic cover off the top of the motor and do it through there. i hope this helps it may be just what was wrong with my truck but i know i was pulling my hair out so i hope this helps someone.


#51 Oct 17, 2009
I have a 2003 1500 and I have been having the dreaded Reduced Engine Problem for two years now. I have tried the dielctric grease on all the connecters that go from the cab to the engine compartment , to no avail. I worked on cars and ran a garage for 30 years and know a lot about mechanical problems , but I have not been able to fix this one. My truck runs rough at times, gives the RDP message at different speeds. It mostly gives it at 55-65 mph. All I have to do is pull over ,count to ten slowly and fire the engine back up and I have full power again. It does this in damp weathers, dry weather, cold weather , hot weather or anytime. I can't help you fix the problem , but if I figure it out will let you know. By the way, it may run great for a week and then do it twelve times withen sixty miles.

Athens, TX

#52 Oct 24, 2009
Rich wrote:
I have a 2003 Chevy silverado HD. I am having idle problems. the truck runs great except for when I come to a stop. When I press the brakes to stop the truck wants to die out. Any suggestions?
PCV valve

Athens, TX

#53 Oct 24, 2009
PCV valve

Jefferson, GA

#54 Oct 24, 2009
Jeff wrote:
<quoted text>
PCV valve
It is a gm problem I guess, I spent a grand on my rep only to have to tell the so called mechanic how to fix it
Is the truck doing this in cold or wet conditions

United States

#55 Nov 2, 2009
Great... MIne just started doing this as well. Engine light came on in the morning on the 12 miles to work. After work I was about 2 miles from my house and I had to drop something off on the way home. I walked back out to my truck and as I reached for the handle it quit. I tried to turn it over and it just cranked. I shut the shut off, counted to 10 and it fired right up. On the way home I got the reduced engine power. Tried to start it when I got home and nothing.

I disconnected the batter for about 60 minutes and then it would start but after a few minutes it was rough. It is at the shop right now and it did it to them once. They looked at the engine codes and for some reason their computer couldn't read them... Great... Looks like I am starting the circle you all did.

Vidalia, GA

#56 Nov 3, 2009
I have a 2003 Chevrolet Silverado 2500 HD with Reduced Engine Power issue as well. It happens very intermittently rain or shine. I just pull over to the side of the road turn off the ignition, wait about a minute then start it up and it runs fine. The check engine light will stay on for three consecutive start and drive sessions then the 4th time the check engine indications goes away. It's amazing there are no law suits for this malfunction. It has happened to me at 70mph on the freeway. Fortunately I was able to coast to the shoulder.. I've read all the posts and have tried most of the solutions suggested. I'll keep watching for a real solution..

Athens, TX

#57 Nov 4, 2009
Rich wrote:
I have a 2003 Chevy silverado HD. I am having idle problems. the truck runs great except for when I come to a stop. When I press the brakes to stop the truck wants to die out. Any suggestions?
pcv valve, and get some throttle body cleaner and clean your throttle body.

Vidalia, GA

#58 Nov 14, 2009
I cleaned the throttle body. It was pretty gummed up. That fixed the rough idle and fluctuating idle between 300 & 500 rpms. now it idles great at 700 rpms. Still got reduced engine power once since i cleaned throttle body. I bought a new Accelerator pedal sensor but it appears I need a special torx screw tool to replace it. It looks like a regular torx screw except it has a raised spot in the center that wont allow you to use a standard torx screwdriver. Thanks for that GM.. I will search for the tool then replace the sensor and see if that resolves the reduced engine power issue.

Vidalia, GA

#59 Nov 14, 2009
Found special trox on-line. It's called Security torx. I'll see if I can find a set at local hardware store or lowes. I'll also get a new PCV valve as Jeff at Athens Tx suggested.. I used to clean or replace them on old vehicles.. Dont even know where its at on this one... I'll find it...
ken g

United States

#60 Dec 12, 2009
I have a 2006 and it is doing the same thing
ken g

United States

#61 Dec 12, 2009
2006 silverado 2500HD diesel runs good but every couple of days my reduced engine power light comes on, and I lose power when it comes on. I have changed the fuel filter thinking it was a clogged fuel line. Does anybody have any suggestions for me? Could there be a recall on this truck because there are so many people having this same problem?
West Virginia
RickC in NC

Greenville, NC

#62 Dec 26, 2009
My son's 20003 Silverado has a drain problem also. Just replaced the battery, no change of course. The starter never turns as strong as I think it should, even when the new battery was put in. Placing the test light between the disconnected positive battery cable and the positive battery post reveals there is a draw on the battery. Disconnecting the alternator, and pulling out each fuse one by one never put out the light. His speakers also went out for a few minutes recently. I have never known a starter to drain a battery, but I guess its possible???? Any remedies that you or anyone found?
mikec wrote:
I have a battrey drain. when it started I could pull my sirus power out of aux power & turn off the radio and it would start ok. now I can't start it after shuting it off for a couple hours. also the drivers side door speaker & door alarm go in&out together.(mostly out I almost never heard them) but I did not miss the alarm so I let it go and didnt think much of it until all this started happning. I have pulled fuses for the radio,radio amp,blower,aux outlet,lighter,sun roof,info,stud#2,aux power2. I have only jump started it. do I need to recharge the battery before I can expect any results. any help would be greatly appreciated. I do construction and am currenly unemployed and this devil truck is the only way I can make money. and I'm so sick of jump starting it.

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