Mechanics

CHEVY REDUCED ENGINE POWER TO SLIGHT HIGH ID

2003 Chevrolet Silverado

Engine Performance problem
2003 Chevy Silverado V8 Four Wheel Drive Automatic 50000 miles

no power at gas pedal have codes p0120 -p0220 -p0758 -p1516 -p1518 -p1860 -when I clear codes they come back
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Jmnneedham
October 3, 2010.




You may have one or two problems here, try removing Ground G103 on the back of the cylinder head, clean both the mating surface and the wire end, use emory cloth and get it nice and brite, re attach ground and cover with RTV. Let me know if this helps, here's the GM TSB on it: CHECK ENGINE LIGHT ON WITH NO DRIVEABILITY CONCERNS, DTC P0120, P0220, P1516, P1518 (CLEAR CODE) TECHNICAL SERVICE BULLETIN Reference Number(s): 03-06-04-032, Date of Issue: June 16, 2003 Related Ref Number(s): 03-06-04-032 ARTICLE BEGINNING CONDITION Some owners may comment that the Check Engine Light is illuminated and there is no driveability concern. Upon investigation, the technician may find codes P0120, P0220, P1516 or P1518. Also, technicians may note that low voltage codes P0562, P0563, P1637 or P1638 have been set. CAUSE The Tach module may set the code in error if it operates at a battery voltage of 4.5 to 5.0 volts. CORRECTION If the vehicle has stored one of the low voltage codes, P0562, P0563, P1637 or P1638, follow the appropriate diagnostics for the low voltage code. In most cases, this will lead to correcting the concern without replacing any Electronic Throttle Control (ETC) components. If codes P0120, P0220, P1516 or P1518 are present without any of the low voltage codes, the technician should observe the Engine RPM in the fault record. If the Engine RPM in the fault record is zero and the customer indicates that the vehicles has experienced a low voltage condition, the code should be cleared and the low voltage should be diagnosed and corrected. If the Engine RPM is zero and the customer indicates that there have been no low voltage conditions, then the P1516 diagnostic aids for intermittent concerns should be used to diagnose and correct the vehicle. If the Engine RPM is greater than zero, then check for an obvious loose ground at G103 located next to the right cylinder head just below the head and mounted into the block. Also, check G104 located behind the left cylinder head. Then verify all electrical connections at the TAC module. If the concern is still not resolved, contact Technical Assistance. CADILLAC: 2003 Escalade, Escalade EXT, Escalade ESV with 4.8L, 5.3L or 6.0L Engine (VINs T, N, U - RPOs LM7, LQ9, LQ4) CHEVROLET: 2003 Avalanche, Silverado, Suburban, Tahoe with 4.8L, 5.3L or 6.0L Engine (VINs V, P, T, Z, N, U - RPOs LR4, LM4, LM7, L59, LQ9, LQ4) GMC: 2003 Sierra, Yukon, Yukon XL with 4.8L, 5.3L or 6.0L Engine (VINs V, P, T, Z, N, U - RPOs LR4, LM4, LM7, L59, LQ9, LQ4) SECTION: 06 - Engine/Propulsion System

Merlin2021
Oct 3, 2010.
Thank you merlin ground cable seem good and intacked should I disconnect really and clean 617-775-8180 john

Tiny
Jmnneedham
Oct 3, 2010.
Pulled off ground and cleaned it also have code p0758 also when try to erase codes they sometimes come right back also sometimes truck will not shut off when you turn off key lights on dash flicker and motor stays sputtering once I put on lights and it shut off whith key in off position of coarse hellp jmn needham

Tiny
Jmnneedham
Oct 3, 2010.

Tiny
Jmnneedham
Oct 3, 2010.
Won't be at my computer till afternoon but will be at truck wait'd for response on sunday desperatly you can callme 617-775-8180

Tiny
Jmnneedham
Oct 4, 2010.
Heyyy, anyone there same problems
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Tiny
Jmnneedham
Oct 4, 2010.
I was asked to assist-check all wiring connections on the PCM if okay have the PCM tested or get it flashed and see what happens-you got too many codes could be one and throwing off the others

You can try testing the throttle position sensor and manifold absolute pressure sensor

Tiny
Rasmataz
Oct 5, 2010.
I had a major 2 drive computer crash, wish I could pick these pieces up like I can with cars. Sorry, to further help I need the engine size in liters, 1500 HD?
Diagnise the P0758 code, and check with Chevy on these others, this group of codes is for several problems, but is supposed to be harness and or ground related. Did you check for ground strap and battery negative connection to the block as well, Might be worth a shot.
P0758= Short to ground or open in + in the 2-3 shift solenoid circuit, so check the wiring harness at the transmission for a good connection and for water intrusion in the connector.
Thanks for the help Jess, I was completely down for a few days, slowley getting off the mat!
Reinstalling all my gear.

Merlin2021
Oct 6, 2010.
I would start by getting it scanned at a chevy or gmc dealer, although it will cost money, they can read the ignition switch actual and read positions, this sounds like an ignition switch issue.

Merlin2021
Oct 6, 2010.
Also check these locations for chaffed wires these are known trouble spots, and can lead to the damage of control modules...
Page 1 of 3 No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs ...
No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs Set or Instrument Panel Cluster (IPC) Warning Indicators, Crank No Start (Inspect/Repair Affected Wiring Harness) TECHNICAL SERVICE BULLETIN Reference Number(s): 03-08-50-014A, Date of Issue: January 20, 2006 2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT; 2003-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe; 2003-2006 GMC Sierra, Yukon, Yukon XL; with Front, Individual (Non-Bkt) Seat (RPO AN3) and/or Active Brake Control (Stabilitrak(R)) (RPO JL4) This bulletin is being revised to update the various conditions and add the 2004-2006 model years, additional diagnostic and warranty information. Please discard Corporate Bulletin Number 03-08-50-014 (Section 08 - Body & Accessories). Related Ref Number(s): 03-08-50-014A Affected Model(s): Supercedes:
ARTICLE BEGINNING
CONDITION
Some customers may comment on any of the following conditions:
Various IPC Warning indicators are coming on. " Driver Information Center (DIC) displays "Unknown Driver". " Memory seat may not recall. " RKE fobs may be inoperative. " Radio or HVAC may shut off. " Engine cranks but will not start. "
Upon investigation, the Technician may find multiple U-DTCs set.
10/7/2010
Page 2 of 3 No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs ...
CAUSE
Fig. 1: Possible Pinch/Chafe Location Courtesy of GENERAL MOTORS CORP.
On RPO AN3 equipped vehicles, a chafed or pinched seat wiring harness under the driver seat may be a cause of this condition. Because of the routing, a portion of the seat wiring harness may rest on the inboard edge of the seat track or frame. Over time, the harness may be pinched or chafed because of the seat movement. Refer to the above illustration. The illustration shows the inverted position of the seat bottom. The arrow shows the primary location of the possible harness chafing/pinching.
Also, on any of the above listed vehicles, the PCM wiring harness may be chafing against the precharge pump bracket (Refer to Document ID# 1252958) or the battery tray.
CORRECTION
On RPO AN3 vehicles, inspect the routing of the seat wiring harness. Reroute the seat wiring harness and attaching harness fastener (1) to the opposite side of the seat module bracket. Repair the harness as necessary. Refer to Wiring Repairs in the Wiring Systems sub-section of SI. The seat may have to be removed for ease of access and proper repair of the wiring harness.
Inspect the routing of the PCM wiring harness at the precharge pump bracket and the battery tray. Repair the harness as necessary. Refer to Wiring Repairs in the Wiring Systems sub-section of SI.
Page 3 of 3 No Communication with Any Modules, Memory Seat May Not Recall, Multiple U-DTCs ...
If any of the above conditions still remain after this repair, refer to SI for further diagnostic information.
WARRANTY INFORMATION
For vehicles repaired under warranty, use:
Warranty Information
Labor OperationDescriptionLabor Time N9542 Wiring and/or Connector - Seat System and/or PCM - Repair 0.2-0.4 hr


http://www.2carpros.com/forum/automotive_pictures/62217_seat_1.jpg


Merlin2021
Oct 6, 2010.

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