I have had many of these trucks with this concern. The most common problem found is the wiring connector at the throttle body on the engine. The wires break inside the connector and the reduce engine power light will come on in the dash. GM has a bulletin, tells you to check the wires comming from the throttlebody. Pull onthe wires at the connector to see if there broken, if they are, replace the connector. The bulletin will tell you not to replace the connector, may cause other codes. I have never had this happen, i have always replaced the connector and fixed the problem. You can get the connector at your local dealer, they should have one instock.
#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|
| ||2003-2006 Cadillac Escalade|
| ||2003-2006 Chevrolet Avalanche, Corvette, Express, Monte Carlo, Silverado, SSR, Suburban, Tahoe, Trailblazer|
| ||2003-2006 GMC Envoy, Savana, Sierra, Yukon|
| ||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.
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.
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)
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.