2008 GMC Yukon

Tiny
ST12
  • MEMBER
  • 2008 GMC YUKON
Engine Performance problem
2008 GMC Yukon V8 Two Wheel Drive Automatic

I would like to know does dostrosk, Posted at Sat May 16, 2009 6:48 pm have reduced engine power after the throttle body was replaced?
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Saturday, May 30th, 2009 AT 3:15 AM

9 Replies

Tiny
BMRFIXIT
  • EXPERT
Can you elaborate
or copy a link to the post you are referring to so we can check it
in general replacing throttle body should not cause a reduce in power what so ever good luck
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Saturday, May 30th, 2009 AT 5:33 AM
Tiny
ST12
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Dear Jack,
I am having problems with my 2008 GMC Yukon having reduced engine power. They have tried to fix it 5 times. They have replaced the PCM & replaced the APP sensor. I noticed this person had the throttle body and pcm replaced and wondered if that fixed his problem? Posted at Sat May 16, 2009 6:48 pm By dostrosk, Have Donated Give Feedback | Votes: 0 Computer problem
2003 Chevy Trailblazer 6 cyl Four Wheel Drive Automatic 175000 miles

Hi,
2003 Chevy Trailblazer-high miles well maintained. Reduced power light started coming on in January this year. Popped codes P1271 and sometimes P1275 and I replaced the accelerator position sensor. It is an intermittent problem where as it will not come on for a few days, then all of a sudden on a cold start it will come on. Shut off restart and comes on for three consecutive start cycles then fine. The TB runs fine no other issues but this code p1271 and reduced engine power light. Seems to do it primarily on a cold start. Replaced the throttle body and had GM dealer
update the PCM with the newest software. Tried jiggling all of the connections to make the fault appear, but no luck. Everything looks intact. There was also a code for the camshaft position sensor and I replaced the sensor-code has not appeared for the CPS since replaced at the same time as the accelerator position sensor. Any ideas on where to look next?
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Saturday, May 30th, 2009 AT 9:10 AM
Tiny
BMRFIXIT
  • EXPERT
We have many TECHNICAL SERVICE BULLETIN
when a message center or an indicator that displays Reduced Engine Power
best if you an get the DTC codes
this is a sample one for your truck
On some vehicles, the IP to body harness connector, which carries the APP signal to the ECM/PCM, is located in the left hand kick panel area or inside the IP. Water intrusion into these areas could cause an electrical short in the APP circuits setting a P2138 code.
Correction
NOTE:Make sure that no add-on/aftermarket equipment is electrically connected to the APP signals or to the other ECM/PCM five volt reference or return lines. These can generate false P2138 and/or other ETC System DTCs. If there are other engine DTCs besides P2138, such as MAP sensor faults (i.E. P0107, P0108), resolve these first before attempting to diagnose P2138 DTCs.

IMPORTANT:Refer to DTC P2138 in SI to confirm that the ETC pedal is operating correctly.

Locate the IP to body harness connector, which may be located in and around the left hand kick panel area or inside the IP. Check to see if there is a water leak into the area and repair as necessary. Use a water hose to determine the source of a water leak and effectiveness of repair. Some examples of potential water leaks are: A-pillar seals, sunroof drain lines (if so equipped) and windshield/cowl sealing. Finally, repair or replace the IP to body harness connector, making sure no corrosion or debris is left on or between the terminals
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Saturday, May 30th, 2009 AT 12:34 PM
Tiny
ST12
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Do you know all of the different reasons my 2008 GMC Yukon could have reduced engine power?
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Saturday, May 30th, 2009 AT 7:46 PM
Tiny
BMRFIXIT
  • EXPERT
Need to have what you have for codes
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Saturday, May 30th, 2009 AT 10:21 PM
Tiny
DOSTROSK
  • MEMBER
Still did not fix the problem. Repleaced the acc pedal sensr, it was good for a week, and then popped several times yesterday. No idea-thinking about getting rid of the vehicle!
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Sunday, July 12th, 2009 AT 12:30 PM
Tiny
BRIAN 1
  • MEMBER
Just to add my 2 cents, I've ran into this problem, you have to relearn the idle with the tech 2 after a throttle cleaning or you will have an idle surge, deceleration RPM surge, and/or tip-in hesitation may be induced. In some case's if there is a drivability problem after cleaning you have to update the ECM with the latest software. As carbon builds up in the throttle body, the ECM/PCM learns to compensate for it so it can control the throttle plate accordingly. If the throttle body is cleaned or replaced for another concern, such as a P0121 DTC, without performing a Tech 2 idle learn reset, a high idle and/or P0507 DTC may be induced. Hope this helps
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Sunday, July 12th, 2009 AT 12:40 PM
Tiny
BRIAN 1
  • MEMBER
Sorry forgot to add that this covers 2006-2008 Chevrolet Trail Blazer

2007-2008 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe

2006-2008 GMC Envoy

2007-2008 GMC Savana, Sierra, Yukon

2007-2008 Hummer H2 vehicles.
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Sunday, July 12th, 2009 AT 12:41 PM
Tiny
BRIAN 1
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Sorry forgot to add this goes for replacing the throttle body also.
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Sunday, July 12th, 2009 AT 12:45 PM

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