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HOMESERVICE MANUALSCHEVROLET2009TAHOE BASE, 4.8 CREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 394 (BATTERY, CHARGING SYSTEM AND STARTING SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESBATTERY ELECTRICAL DRAIN/PARASITIC LOAD TESTCIRCUIT/SYSTEM TESTING
2009 Chevrolet Tahoe Base, 4.8 C

Circuit/System Testing

2009 Chevrolet Tahoe Base, 4.8 CSECTION Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
  • Removing or installing a fuse, relay, or connector, to determine the area causing high parasitic draw may wake up control modules. You must wait for the control modules to go back to sleep before retesting. It is best to install any removed or disconnected components after the diagnosis is completed.
  • Fuses for power mode master components such as the BCM should be removed last to avoid misdiagnosis.
  • If a scan tool is connected to the DLC, either disconnect it or subtract the scan tool current draw from the DMM reading to get the actual vehicle parasitic current draw.

If the vehicle has an unacceptable amount of parasitic current draw, remove each fuse one at a time until the current draw falls to an acceptable level. A drop of more than 10-20 mA, when disabling a single system or circuit, is an indication of an overly high current draw that could be causing the battery drain. Refer to Power Distribution Schematics to diagnose exactly which circuit of the suspect system is causing the high parasitic drain. The following is a list of common components that could cause a high current draw:

  • Stuck switch
  • Stuck relay
  • Control module
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