Reduced power mode

Tiny
FLYBOY69
  • MEMBER
  • 2003 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 145,000 MILES
I own a 2003 Chevrolet 2500HD, with the 6.0l engine. During the summer time I do not have many problems with it, but when the weather starts getting cold it will run for 10 to 15 mins then go into reduced power mode. I have changed out the water pump and the thermostat. What do you think is wrong with it?
Do you
have the same problem?
Yes
No
Friday, December 24th, 2010 AT 2:25 AM

8 Replies

Tiny
FACTORYJACK
  • EXPERT
Typically, what triggers the system to go into limp home(reduced power) is a fault that relates to the throttle actuator or accelerator pedal position assembly. Ideally, you should seek the trouble code that is associated with it. One crucial concern, is does it have any aftermarket stuff installed? There may be a bulletin that states(depending on the code) the throttle body or body connector could be cause, and it could be. I have seen instances where this was followed, only to have the fault reoccur, and it eventually was ruled to aftermarket installations into critical circuits. The electronic throttle is run on 5 volt potential, so some resistance that would go unnoticed in a 12 volt circuit, causes intermittent problems in a 5 volt circuit.
Was this
answer
helpful?
Yes
No
+1
Friday, December 24th, 2010 AT 3:43 AM
Tiny
FLYBOY69
  • MEMBER
There are no after market items on the engine. I will get a code readerand post that in a few days.
Was this
answer
helpful?
Yes
No
+1
Friday, December 24th, 2010 AT 4:54 PM
Tiny
FLYBOY69
  • MEMBER
Okay, I got a scanner and the two codes that are popping are P1516 & P0171. Should I remove and replace the throttle body or is there a check that I can do before I go out and spend $200.00 for that part? Thank you for your help!
Was this
answer
helpful?
Yes
No
+1
Friday, January 7th, 2011 AT 7:19 PM
Tiny
FACTORYJACK
  • EXPERT
The P0171 is a lean code for one bank of cylinders. It would not result in a reduced power message. I would clear it and see if it returns over time. The P1516 will result in reduced power. There is a bulletin I included for reference, may or may not apply, but gives a starting point.

#PIP3089B: SES Light And Reduced Engine Power DTC P0120 P0220 P1516 P2135 - keywords accelerator actuator APP blade body connector connection DTC L33 L59 LH6 LR4 LM7 LS1 LS2 LQ4 LQ9 module position reduce sensor - (Oct 31, 2006)

Subject: SES Light and Reduced Engine Power DTC P0120 P0220 P1516 P2135

Models: 2004-2006 Buick Rainer

2005-2006 Cadillac CTS-V

2003-2006 Cadillac Escalade

2003-2006 Chevrolet Avalanche, Corvette, Express, Monte Carlo, Silverado, SSR, Suburban, Tahoe, Trailblazer

2003-2006 GMC Envoy, Savana, Sierra, Yukon

2003-2006 Hummer H2

2005-2006 Pontiac GTO

Equipped with a 4.8 5.3 6.0 or 7.0 V-8 Engine

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
A vehicle may be brought into the dealer for a reduced power message, and DTCs P0120, P0220, P1516, P2101, or P2135.

The Throttle Actuator Control (TAC) / throttle body type trouble codes, may be caused by a loose wiring crimp at the throttle body connector, or a broken throttle body circuit.

Recommendation/Instructions:
Complete the current SI diagnostics for any symptoms or trouble codes found. If a intermittent T/P or TAC module type code is occurring complete the inspections below.

Inspect all related throttle body terminals for a loose wiring crimp. The loose crimp may be difficult to find, and the poor connection will be between the terminal and the copper strands of the wire. Wiggle test the individual throttle body circuits to see if the concern can be duplicated.
Inspect the related circuits for broken wires inside the insulation. The outer wire insulation may look fine, but the internal copper strands may be partially broken. Breaks in the wires usually occur within 1 to 4 inches of the throttle body connector. Wiggle testing may also induce a trouble code to set.
On C/K trucks complete SI procedures for voltage drop on grounds G103 and G104. Grounds G103 or G104 may be loose or corroded.
If a terminal crimp or a broken wire has been found, repair or replace only the circuits involved. There is a throttle body pigtail connector available through GMSPO, but installing this pigtail connector may cause other intermittent TAC module/TP codes at a later date. If this pigtail must be used, please follow the SI procedures for Splicing Copper Wire Using Splice Sleeves. (The proper Kent-Moore crimping tool must be used for this repair).

The test chart for that code involves some circuit testing, and may be most streamlined with a scan tool that can display data. Often times this code can be hard to duplicate. If I were to start somewhere, it would be splicing a new connector at the throttle body.
Was this
answer
helpful?
Yes
No
+2
Sunday, January 9th, 2011 AT 3:58 AM
Tiny
CHIEF_FL
  • MEMBER
I had the same problem and found two broken wires 3/4" from the throttle body plug. Two butt connectors and back in business.
Was this
answer
helpful?
Yes
No
+1
Tuesday, June 19th, 2012 AT 1:23 PM
Tiny
RIVERMIKERAT
  • MEMBER
Thanks for the heads up Chief_FI.

Flyboy did you ever get this diagnosed and fixed, or do we need to do more testing and diagnosing?
Was this
answer
helpful?
Yes
No
Monday, July 30th, 2012 AT 3:52 AM
Tiny
LARRY@888CARHELP.COM
  • MEMBER
My 2003 Silverado 2500HD 6.0 has a "service brake booster? Message in the DIC - how can I reset it? I don't believe there is a problem as everything works great! Thanks for your help.
Was this
answer
helpful?
Yes
No
Monday, January 29th, 2018 AT 12:07 PM
Tiny
KEN
  • ADMIN
Please post your question here

https://www.2carpros.com/questions/new

Cheers, Ken
Was this
answer
helpful?
Yes
No
+1
Friday, February 2nd, 2018 AT 1:44 PM

Please login or register to post a reply.

Recommended Guides