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Home >> Chevrolet >> 2006 >> Silverado 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1149 (Engine Controls And Fuel - 3.6L - DTC P0137 To DTC P0497) >> DTC P0201-P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D (w/LLT) >> Circuit/System Testing (w/LLT)

Circuit/System Testing (w/LLT)

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition ON, clear the DTC information with a scan tool.
  2. Ignition OFF, disconnect the appropriate fuel injector multi-way harness connector at the rear of the intake manifold.
    3. IMPORTANT:
    • Testing for steps 3 through 5 is performed on the ECM side of the multi-way harness connector.
    • The test lamp should flash several times and then stop when the DTC sets.
  3. Engine cranking, verify that a test lamp flashes between the appropriate high voltage control circuit terminal and ground.
      IMPORTANT: Four of the injector high voltage control circuits are paired in the controller with a dual driver, refer to Diagnostic Aids .
    • If the test lamp is always ON, test the circuit(s) for a short to voltage. If the circuit tests normal, replace the ECM.
    • If the test lamp is always OFF, test the circuit(s) for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Clear the DTC information with a scan tool, then cycle the ignition OFF for 30 seconds.
  5. Engine cranking, verify that a test lamp flashes dimly between the appropriate low voltage control circuit terminal and B+.
    • If the test lamp is always ON, test the circuit for a short to ground. If the circuit tests normal, replace the ECM.
    • If the test lamp is always OFF, test the circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
    6. IMPORTANT: Testing for steps 6 and 7 is performed on the fuel injector side of the multi-way harness connector. It may be necessary to remove the upper intake manifold to isolate the condition.
  6. Ignition OFF, test for OL ohms between the appropriate ignition high voltage control circuit and ground.
    • If less than the specified range, test the high voltage, or low control circuit, for a short to ground. If the circuits/connections test normal, test or replace the appropriate fuel injector(s).
  7. Test for 1.5-2.5 ohms between the appropriate high voltage control and low voltage control circuit.
    • If less than the specified range, test for a short between the high voltage and low voltage control circuit. If the circuits/connections test normal, test or replace the appropriate fuel injector(s).
    • If greater than the specified range, test the high voltage and low voltage control circuit, for an open/high resistance. If the circuits/connections test normal, test or replace the appropriate fuel injector(s).
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