Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2004EXPRESS 1500 RWD V6-4.3L VIN XREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTPROM - PROGRAMMABLE READ ONLY MEMORYTECHNICAL SERVICE BULLETINSCUSTOMER INTERESTENGINE CONTROLS - LACK OF POWER WHEN HOT
2004 Chevrolet Express 1500 RWD V6-4.3L VIN X
Engine Controls - Lack of Power When Hot
2004 Chevrolet Express 1500 RWD V6-4.3L VIN XSECTION Engine Controls - Lack of Power When Hot
Bulletin No.: 05-06-04-077
Date: December 22, 2005
TECHNICAL
Subject:
Lack of Power (LU3 Engine) at High Ambient Temperatures Only (If Necessary, Reprogram PCM with New Service Calibration)
Models:
2003-2005 Chevrolet Astro, Blazer, Express, S-10, Silverado
2003-2005 GMC Jimmy, Safari, Savana, Sierra, Sonoma
with 4.3L Vortec(TM) V6 Engine (VIN X - RPO LU3)
Condition
Some customers may comment that the vehicle may exhibit a lack of power at high ambient temperatures.
Cause
Engineering has identified a concern with the PCM software. In high ambient temperatures, the engine control management system may falsely retard the timing, causing a noticeable loss of power.
Correction
Important:
Before Reprogramming the PCM, verify the customer concern. Refer to SI Engine Controls and under Diagnostic Information and Procedures. Refer to Lack of Power, Sluggishness, or Sponginess for the cause of the low power condition at high ambient temperatures. If no trouble is found, then reprogram the PCM.
Reprogram the PCM with the latest calibrations if the above concern is encountered. An updated PCM calibration is now available to address this concern. This calibration, or any that follow, is designed to address this concern. Refer to Service Programming System (SPS) using the appropriate Service Information (SI) procedures. The new PCM calibrations will be available to dealerships as part of TIS2000 incremental satellite update version 12.5, which was broadcast to dealers on 12/11/2005. For the dealerships that use CDs, the CD version will be 1.0 for 2006, which will be mailed 0111212006. As always, make sure your Tech 2(R) is updated with the latest software version.
Warranty Information
For vehicles repaired under warranty use the table.
Disclaimer
Date: December 22, 2005
TECHNICAL
Subject:
Lack of Power (LU3 Engine) at High Ambient Temperatures Only (If Necessary, Reprogram PCM with New Service Calibration)
Models:
2003-2005 Chevrolet Astro, Blazer, Express, S-10, Silverado
2003-2005 GMC Jimmy, Safari, Savana, Sierra, Sonoma
with 4.3L Vortec(TM) V6 Engine (VIN X - RPO LU3)
Condition
Some customers may comment that the vehicle may exhibit a lack of power at high ambient temperatures.
Cause
Engineering has identified a concern with the PCM software. In high ambient temperatures, the engine control management system may falsely retard the timing, causing a noticeable loss of power.
Correction
Important:
Before Reprogramming the PCM, verify the customer concern. Refer to SI Engine Controls and under Diagnostic Information and Procedures. Refer to Lack of Power, Sluggishness, or Sponginess for the cause of the low power condition at high ambient temperatures. If no trouble is found, then reprogram the PCM.
Reprogram the PCM with the latest calibrations if the above concern is encountered. An updated PCM calibration is now available to address this concern. This calibration, or any that follow, is designed to address this concern. Refer to Service Programming System (SPS) using the appropriate Service Information (SI) procedures. The new PCM calibrations will be available to dealerships as part of TIS2000 incremental satellite update version 12.5, which was broadcast to dealers on 12/11/2005. For the dealerships that use CDs, the CD version will be 1.0 for 2006, which will be mailed 0111212006. As always, make sure your Tech 2(R) is updated with the latest software version.
Warranty Information
For vehicles repaired under warranty use the table.
Disclaimer
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.