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Home >> Chevrolet >> 2006 >> Uplander Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 182 (Battery, Charging System And Starting System) >> Diagnostic Information and Procedures >> DTC P0621 >> 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 ignition ON, and the engine OFF.
  2. Disconnect the generator harness and measure the voltage of the generator turn on signal circuit, should read near 0 volt.
    • If greater than 0 volt, test the generator turn on signal circuit for a short to voltage, or replace the ECM.
  3. With ignition ON, and the engine running, the voltage of the generator turn on signal circuit, should read near 5 volts.
    • If no voltage is measured, test the generator turn on signal circuit for a short to ground, an open or a high resistance or replace the ECM.
  4. Go to Charging System Test .
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