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Home >> Chevrolet >> 2006 >> Uplander Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 169 (Computer/Integrating Systems) >> Diagnostic Information and Procedures >> DTC B1428 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2006 Chevrolet Monte Carlo and 2006 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. With the ignition OFF, disconnect the IGN MAIN PCB relay and connect a test lamp between the relay control circuit and ground.
  2. Cycle the ignition ON and OFF. The test lamp should turn ON and OFF when changing ignition switch positions.
    • If the test lamp remains OFF all the time, test for a short to ground or an open/high resistance on the relay control circuit. If the circuit tests normal, replace the BCM.
    • If the test lamp remains ON all the time, test for a short to voltage on the relay control circuit. If the circuit tests normal, replace the BCM.
  3. If test lamp turns ON and OFF normal, test or replace the IGN MAIN PCB relay.
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