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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1370 (Automatic Transmission - 4L60-E - DTC P0218 To DTC P2771) >> DTC P2771 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove connector from the transfer case control module. With ignition ON and engine OFF, observe with the scan tool the 4WD Low parameter.
    • If the scan tool indicates Enabled, test the 4WD Low signal circuit for a short to ground.
  2. Using the J 35616  GM-approved terminal test kit, install a fused jumper between the 4WD low signal circuit and ground at the transfer case control module connector.
    • If the scan tool 4WD Low parameter indicates Enabled when grounded, replace the transfer case control module.
  3. Test the 4WD Low signal circuit for an open.
    • Fix the open in the 4WD Low circuit.
  4. Replace the ECM.
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