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Home >> Buick >> 2007 >> Allure CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 64 (Engine Control System & Fuel System - 3.6L - DTC P0008 To DTC P0333) >> DTC P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, or P0277 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the fuel injector multi-way harness connector C109.
    2. IMPORTANT: Testing for steps 2 through 4 is performed on the ECM side of the multi-way harness connector.
  2. Ignition ON, load test for B+ between the appropriate ignition voltage supply circuit and ground.
    • If less than the specified range, repair the ignition voltage circuit for a short to ground, or an open/high resistance. Replace the fuse if necessary.
  3. Test for 2.6-4.6 volts between the appropriate fuel injector control circuit and ground
    • If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Probe the appropriate fuel injector control circuit with a test lamp connected to B+. Engine cranking, verify the test lamp flashes.
    • If the test lamp remains OFF, test the control circuit for a high resistance. If the circuit/connections test normal, replace the ECM.
    5. IMPORTANT: Testing for steps 5 and 6 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. Refer to Upper Intake Manifold Replacement .
  5. Ignition OFF, test for OL ohms between the appropriate ignition voltage circuit and ground.
    • If less than the specified range, repair the ignition voltage, or control circuit, for a short to ground. If the circuits/connections test normal, test or replace the appropriate fuel injector(s).
  6. Test for 12-16 ohms between the appropriate ignition voltage circuit and each fuel injector control circuit.
    • If less than the specified range, test for a short between the control circuit and the ignition voltage circuit. If the circuits/connections test normal, test or replace the appropriate fuel injector(s).
    • If greater than the specified range, test the ignition voltage, and fuel injector 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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